8623 Prelims pp i_xvi
Mastering
Financial
Calculations
market editions
Mastering
Financial
Calculations
A step-by-step guide to the mathematics
of financial market instruments
ROBERT STEINER
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First published in Great Britain 1998
Reprinted and updated 1999
© Robert Steiner 1998
The right of Robert Steiner to be identified as author of this work has been asserted
by him in accordance with the Copyright, Designs and Patents Act 1988.
ISBN 0 273 62587 X
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About the Author
Robert Steiner is Managing Director of Markets International Ltd, an independent company specializing in training in a range of areas related to the
international financial markets, treasury and banking. The company also
provides advice to finance directors and treasurers of international companies on foreign exchange, money markets and other treasury matters. This
advice ranges from written studies reviewing existing management policies
and procedures, through the development of appropriate hedging strategies,
to short-term market advice.
Robert was previously senior consultant with HongKong and Shanghai
Banking Corporation, where he worked in London and New York in the
dealing area as consultant to major US and European companies on treasury
management. He has also been treasurer and fund manager of H P Bulmer
Holdings PLC and English and American Insurance Group PLC, active in
currency and interest rate management. He has thus been closely involved
in treasury management as consultant and practitioner. He has also worked in
the Overseas Department of the Bank of England, and with the European
Commission in Brussels.
Robert spends a considerable amount of time training bankers, systems
staff, corporate staff and others involved in the financial markets. In particular, he personally runs courses for several of the ACI exams – the ACI
Diploma, the Dealing Certificate, Repo Markets and the Settlements
Certificate. He is the author of Mastering Repo Markets, also published by
Financial Times Prentice Hall.
His academic background is an honours degree in mathematics from
Cambridge University followed by further studies in economics with London
University. He is an associate member of ACI UK, and a member of the
Association of Corporate Treasurers.
TO MY PARENTS
without whom none of this would have been possible
AND TO MY FAMILY
who have suffered while I’ve been writing it
CONTENTS
Foreword
Introduction
xi
xiii
Part 1: THE BASICS
1
Financial Arithmetic Basics
Some opening remarks on formulas
Use of an HP calculator
Simple and compound interest
Nominal and effective rates
Future value / present value; time value of money
Discount factors
Cashflow analysis
Interpolation and extrapolation
Exercises
3
4
4
5
10
12
15
17
23
25
Part 2: INTEREST RATE INSTRUMENTS
2
The Money Market
Overview
Day/year conventions
Money market instruments
Money market calculations
Discount instruments
CDs paying more than one coupon
Exercises
3
Forward-Forwards and Forward Rate Agreements (FRAs)
Forward-forwards, FRAs and futures
Applications of FRAs
Exercises
29
30
32
34
38
40
43
47
51
52
58
60
vii
Contents
4
Interest Rate Futures
Overview
Exchange structure and margins
Futures compared with FRAs
Pricing and hedging FRAs with futures
Trading with interest rate futures
Exercises
5
Bond Market Calculations
Overview of capital markets instruments
Features and variations
Introduction to bond pricing
Different yield measures and price calculations
A summary of the various approaches to price / yield
Duration, modified duration and convexity
Bond futures
Cash-and-carry arbitrage
Exercises
6 Zero-Coupon Rates and Yield Curves
Zero-coupon yields and par yields
Forward-forward yields
Summary
Longer-dated FRAs
Exercises
63
64
66
67
69
74
79
81
82
84
86
95
105
107
114
121
130
135
136
140
142
143
146
Part 3: FOREIGN EXCHANGE
7
Foreign Exchange
Introduction
Spot exchange rates
Forward exchange rates
Cross-rate forwards
Short dates
Calculation summary
Value dates
Forward-forwards
Time options
Long-dated forwards
Synthetic agreements for forward exchange (SAFEs)
Arbitraging and creating FRAs
Discounting future foreign exchange risk
Exercises
viii
149
149
150
156
167
169
171
172
173
175
176
176
181
186
189
Contents
Part 4: SWAPS AND OPTIONS
8 Interest Rate and Currency Swaps
Basic concepts and applications
Pricing
Valuing swaps
Hedging an interest rate swap
Amortising and forward-start swaps
Currency swaps
Exercises
9 Options
Overview
The ideas behind option pricing
Pricing models
OTC options vs. exchange-traded options
The Greek letters
Hedging with options
Some “packaged” options
Some trading strategies
Some less straightforward options
Exercises
195
196
200
208
213
214
216
218
221
222
223
228
237
238
242
244
246
252
254
Part 5: FURTHER EXERCISES, HINTS AND ANSWERS
10 Further exercises
257
11 Hints and Answers to Exercises
263
264
276
316
Hints on exercises
Answers to exercises
Answers to further exercises
Appendix 1 Using an HP calculator
Appendix 2 A summary of market day/year conventions
Appendix 3 A summary of calculation procedures
Appendix 4 Glossary
Appendix 5 ISO (SWIFT) codes for currencies
Select Bibliography
Index
329
337
341
359
381
387
389
ix
FOREWORD
ACI Education (formerly The ACI Institute) is the educational division of
ACI – the Financial Markets Association, the primary international professional body for the international financial markets, founded in 1955 and
now represented in 59 countries internationally with over 24,000 members.
The task of ACI Education is simple to state and is embodied in the
Charter of ACI. It is to ensure that educational programmes that reflect the
constantly changing nature of the industry are made available to both new
entrants to the profession and seasoned professionals, and to set professional
standards for the industry globally. This task is both challenging and exciting. Recent innovations include the decision to convert the examinations to
an electronically delivered format, a change that will facilitate the availability
of ACI’s professional testing programme, on a daily basis via a network of
over 2,000 test centres globally.
One of the component ACI examinations is the Level 2 ACI Diploma that
has been running successfully since 1990. Research into ACI’s large database
of results yields some interesting findings. Among these it can be seen that
one of the best predictors of overall success in the examination has been a
good performance on the part of the candidate in the financial calculations
section. Conversely, candidates performing badly in this section have often
performed poorly, overall, in the examination.
ACI, as part of its educational programmes encourages authors, publishers
and tutors to provide a wide variety of routes to its examinations as possible.
For this reason it is delighted that Robert Steiner and Financial Times
Prentice Hall have produced Mastering Financial Calculations. It captures the
professional knowledge necessary to appreciate fully the topic, and provides
an excellent additional source of study for both the ACI Dealing Certificate
and key sections of the ACI Diploma. It also believes that the publication will
be appreciated not only by examination candidates but also by the market
professionals seeking an ‘easy-to-read’ reference manual on this highly
important subject.
Heering Ligthart
President
ACI – The Financial Markets Association
xi
INTRODUCTION
The aim of the book
This book is aimed at the very many people in financial institutions, universities and elsewhere who will benefit from a solid grounding in the calculations
behind the various financial instruments – dealers, treasurers, investors, programmers, students, auditors and risk managers – but who do not necessarily
do complex mathematical puzzles for fun. There is also a strong emphasis on
the mechanics, background and applications of all the various instruments.
Many dealers would claim to be able to perform their job – essentially
buying and selling – very profitably, without using much maths. On the other
hand, the different dealing areas in a bank overlap increasingly and it is
essential to understand the basis for pricing each instrument, in order to
understand how the bank’s position in one relates to a position in another.
Almost all the concepts in this book regarding pricing the different instruments can be reduced to only two basic ideas. The first concerns the ‘time
value of money’: a hundred dollars is worth more if I have it in my hand
today than if I do not receive it until next year; or alternatively, for a given
amount of cash which I will receive in the future, I can calculate an equivalent ‘present value’ now. The second is the ‘no free lunch’ principle: in
theory, it should not generally be possible to put together a series of simultaneous financial transactions which lock in a guaranteed no-risk profit. For
example, if a dealer buys an interest rate futures contract and simultaneously
reverses it with an FRA, he will in general make no profit or loss if we ignore
minor mechanical discrepancies and transaction costs. This concept links the
pricing calculations for the two instruments. If the reader has a clear grasp by
the end of the book of how to apply these two crucial concepts, he/she will
be well equipped to cope. Much of the difficulty lies in seeing through the
confusion of market terminology and conventions.
There is a significant jump between the arithmetic needed for most instruments, and the complex mathematics needed to construct option pricing
formulas from first principles. I have deliberately excluded much of the latter
from this book, because many readers are more likely to be discouraged than
helped, and because that subject alone warrants an entire book. On the other
hand, I have discussed the ideas behind option pricing, particularly volatility,
which introduce the concepts without being mathematically frightening. I
have also included the Black–Scholes formula for reference and mentioned
standard books on the subject for those interested.
xiii
Introduction
The book has been conceived as a workbook, as well as a reference book,
with an emphasis on examples and exercises. It has grown out of workshops
on financial mathematics which I have run for many years, including some for
the ACI’s former Financial Calculations exam. The book is therefore also suitable for the student who chooses to take exams without any formal tuition
course. There is however considerably more background material than is
required for any exam aimed specifically at calculations. The intention is to
benefit the reader technically as well as making the book more readable.
The structure of the book
The book is set out in five parts:
The basics
This covers the fundamental concepts of time value of money, discounting,
present values and calculations with interest rates.
Interest rate instruments
This looks at the range of instruments based on interest rates or yields in both the
money markets and capital markets – simple deposits, CDs, bills and CP, FRAs
and futures, and bonds. The market background and use for each instrument is
given as a structure within which to see the calculations. This section also covers
zero coupon rates, yield curves, duration and convexity.
Foreign exchange
This looks at all the foreign exchange instruments from basic spot, through
swaps, outrights, short dates, forward-forwards and time options, to SAFEs.
Again, the context of each instrument in the market is explained, together
with the link with the money markets.
Swaps and options
This part explains both interest rate and currency swaps, and options.
Examples are given of the basic uses as well as some of the combination
option strategies. It also introduces option pricing concepts and the ‘Greeks’.
Further exercises, hints and answers
This section begins with some further exercises covering several areas of the
book for readers who would like more practice. These are followed by hints
and answers to the exercises which are found throughout the book.
Key features of the book
Key points
Throughout the book, key points have been highlighted for emphasis.
xiv
Introduction
Calculation summaries
The procedures for all the necessary calculations have been summarized in
the text to ensure the reader’s understanding. These have also been collected
together into a reference section in Appendix 3.
Glossary
The market terminology is explained throughout the text, with a glossary for
reference in Appendix 4.
Market interest conventions
A constant source of confusion is the range of different conventions used for
interest and coupon calculations in different markets. These are also summarized in Appendix 2 for various countries’ markets.
Examples
Many examples to help the reader’s understanding have been included
throughout the text.
Exercises
Fully worked answers are provided at the end of the book in Chapter 11 for
each chapter’s exercises and for the further exercises in Chapter 10. The
exercises form an important part of the book as they provide further examples of the calculations covered in the text. Readers who do not wish to
attempt them as exercises should therefore read them as worked examples.
For the reader who is struggling with a particular question but who wishes to
persevere, there is a section of hints, which will lead him/her through the procedure to be followed for each question.
Calculator keystrokes
Many of the examples and answers include the full keystroke procedures necessary using a Hewlett Packard calculator. The use of an HP calculator is
described in detail in Appendix 1.
A final word
However hard one tries, there are always mistakes. I apologize for these
and welcome comments or suggestions from readers – particularly on
other areas which might usefully be included in the book without making
it too boffin orientated. As always, I am hugely indebted to my wife for
her support throughout.
xv
Part 1
The Basics
1
■
■
■
“The fundamental principle
behind market calculations is the
time value of money: as long as
interest rates are not negative,
any given amount of money is
worth more sooner than it is
later because you can place it on
deposit to earn interest.”
2
1
Financial Arithmetic Basics
Some opening remarks on formulas
Use of an HP calculator
Simple and compound interest
Nominal and effective rates
Future value/present value; time value of money
Discount factors
Cashflow analysis
Interpolation and extrapolation
Exercises
3
Part 1 · The Basics
SOME OPENING REMARKS ON FORMULAS
There are three important points concerning many of the formulas in this
book. These have nothing to do with the business of finance, but rather with
how mathematical formulas are written in all areas of life.
First, consider the expression “1 + 0.08 × —
´ow¥†”. In this, you must do the
multiplication before the addition. It is a convention of the way mathematical formulas are written that any exponents (54, x2, 4.2q-® etc.) must be done
qu
first, followed by multiplication and division (0.08 × 92, x ÷ y, _
´^ etc.) and
addition and subtraction last. This rule is applied first to anything inside
ow¥†” is
brackets “(...)” and then to everything else. This means that “1 + 0.08 × ´—
the same as “1 + (0.08 × —
´ow
¥†)” and is equal to 1.0202. This is not the same as
“(1 + 0.08) × —
´ow¥†”, which is equal to 0.2722. If I mean to write this latter
expression, I must write the brackets. If I mean to write the first expression, I
do not need to write the brackets and it is in fact usual to leave them out.
Second, the expression “per cent” means “divided by 100.” Therefore
.
“4.7%”, “—
œrππu ” and “0.047” are all the same. When writing a formula which
involves an interest rate of 4.7 percent for example, this usually appears as
rππ.u ”, simply because “0.047” is neater. Similarly, when
“0.047” rather than “œ—
we speak of an “interest rate i,” we mean a decimal such as 0.047, not a
number such as 4.7.
Third, the symbol ∑ is shorthand for “the sum of all.” Thus for example,
“∑ (cashflow)i” is shorthand for “cashflow1 + cashflow2 + cashflow3 + ....”
Where there are many cashflows, this is a very useful abbreviation.
USE OF AN HP CALCULATOR
Some of the calculations used in financial arithmetic are mostly easily performed using a specialist calculator. The ones most widely used in the
markets are probably Hewlett Packard calculators. In many of the worked
examples and exercises in this book, as well as showing the method of calculation, we have therefore also given the steps used on an HP. It is important
to understand that you do not need an HP in order to work through these
examples. An ordinary non-financial calculator is fine for many calculations,
and you can use an alternative specialist calculator – or a computer spreadsheet – for the rest. We have chosen to show the steps for an HP simply
because many readers will already have access to one, and because it is recommended for use in the ACI Financial Calculations exam.
In order to make these steps intelligible to anyone new to an HP, we have
explained the basics of operating the calculator in Appendix 1. We have certainly not tried to give full instructions for using an HP – the calculator’s
own instruction manual is clearly the best place for that – but have set out
only those operations which are necessary for our examples.
4
1 · Financial Arithmetic Basics
SIMPLE AND COMPOUND INTEREST
Simple interest
On short-term financial instruments, interest is usually “simple” rather than
“compound”. Suppose, for example, that I place £1 on deposit at 8 percent
for 92 days. As the 8 percent is generally quoted as if for a whole year rather
than for only 92 days, the interest I expect to receive is the appropriate proportion of 8 percent:
ow¥†
£0.08 × ´—
The total proceeds after 92 days are therefore the return of my principal,
plus the interest:
ow¥†)
£(1 + 0.08 × ´—
If I place instead £73 on deposit at 8 percent for 92 days, I will receive a
total of:
ow¥†)
£73 × (1 + 0.08 × ´—
(
Total proceeds of short-term investment = principal × 1 + interest rate ×
days
year
)
Calculation
summary
“ days ”
“ number of days in the period ”
we mean
.
year
number of days in the year
In this chapter “number of days in the year” generally means 365. In some
markets, however, (as explained in Chapter 2) this number is 360 by convention. Where this might be the case, we have therefore used “year” to cover
either situation.
By
Compound interest
Now consider an investment of 1 made for two years at 10 percent per
annum. At the end of the first year, the investor receives interest of 0.10. At
the end of the second year he receives interest of 0.10, plus the principal of 1.
The total received is 0.10 + 0.10 + 1 = 1.20. However, the investor would in
practice reinvest the 0.10 received at the end of the first year, for a further
year. If he could do this at 10 percent, he would receive an extra 0.01 (= 10
percent × 0.10) at the end of the second year, for a total of 1.21.
In effect, this is the same as investing 1 for one year at 10 percent to receive
1 + 0.10 at the end of the first year and then reinvesting this whole (1 + 0.10)
for a further year, also at 10 percent, to give (1 + 0.10) × (1 + 0.10) = 1.21.
The same idea can be extended for any number of years, so that the total
return after N years, including principal, is:
Principal × (1 + interest rate)N
5
Part 1 · The Basics
This is “compounding” the interest, and assumes that all interim cashflows
can be reinvested at the same original interest rate. “Simple” interest is when
the interest is not reinvested.
Calculation
summary
Total proceeds of long-term investment for N years
= principal × (1 + interest rate)N
Nominal rates and effective rates
Now consider a deposit of 1 made for only one year at 10 percent per
annum, but with quarterly interest payments. This would mean interest of
0.025 received each quarter. As above, this could be reinvested for a further
quarter to achieve interest-on-interest of 0.025 × 0.025 = 0.000625. Again,
this is the same as investing 1 for only three months at 10 percent per annum
(that is, 2.5 percent per quarter) to receive (1 + 0.025) at the end of the first
quarter and then reinvesting this whole (1 + 0.025) for a further quarter, also
at the same interest rate, and so on for a total of four quarters. At the end of
this, the total return, including principal is:
(1 + 0.025) × (1 + 0.025) × (1 + 0.025) × (1 + 0.025) = (1 + 0.025)4 = 1.1038
The same idea can be extended for monthly interest payments or semi-annual
(6-monthly) interest payments, so that in general the proceeds at the end of a
year including principal, with n interest payments per year, are:
(
Principal × 1 +
interest rate
n
)
n
It is often useful to compare two interest rates which are for the same investment period, but with different interest payment frequency – for example, a
5-year interest rate with interest paid quarterly compared with a 5-year rate
with interest paid semi-annually. To do this, it is common to calculate an
equivalent annualized rate. This is the rate with interest paid annually which
would give the same compound return at the end of the year as the rate we
are comparing. From this it follows that:
(
Principal × 1 +
interest rate
n
) = Principal × (1 + equivalent annual rate)
n
Thus if the interest rate with n payments per year is i, the equivalent annual
interest rate i* is:
Calculation
summary
6
i* =
[(1 + ni ) –1]
n
1 · Financial Arithmetic Basics
This equivalent annual interest rate i* is known as the “effective” rate. The rate i
from which it is calculated is known as the “nominal” rate. It follows that:
[
1
n
]
i = (1 + i*) –1 × n
Calculation
summary
Example 1.1
8% is the nominal interest rate quoted for a 1-year deposit with the interest paid in
quarterly instalments. What is the effective rate (that is, the equivalent rate quoted
when all the interest is paid together at the end of the year)?
[(
1+
0.08
4
) –1] = 8.24%
4
Answer: 8.24%
Using an HP-19BII
.08 ENTER
4÷1+
4■∧
1–
Example 1.2
5% is the nominal interest rate quoted for a 1-year deposit when the interest is
paid all at maturity. What is the quarterly equivalent?
[
1
]
(1.05) 4 –1 × 4 = 4.91%
Answer: 4.91%
1.05 ENTER
4 ■ 1/x ■ ∧
1-4x
In the same way, we might for example wish to compare the rate available on a
40-day investment with the rate available on a 91-day investment. One
approach, as before, is to calculate the effective rate for each. In this case, the
365
effective rate formula above can be extended by using the proportion days
instead
of the interest rate frequency n.
7
Part 1 · The Basics
Example 1.3
The interest rate for a 5-month (153-day) investment is 10.2%. What is the effective rate?
(
Effective rate = 1 + i ×
days
year
(
Effective rate = 1 + 0.102 ×
)
365
days
153
365
–1
)
365
153
–1 = 10.50%
.102 ENTER 153 x 365 ÷ 1 +
365 ENTER 153 ÷ ■ ∧ 1 -
Calculation
summary
(
Effective rate = 1 + i ×
days
year
)
365
days
–1
Continuous compounding
The effect of compounding increases with the frequency of interest payments,
because there is an increasing opportunity to earn interest on interest. As a
result, an annual rate will always be greater than the semi-annual equivalent,
which in turn will always be greater than the monthly equivalent, etc. In practice, the limit is reached in considering the daily equivalent rate. Thus the
equivalent rate with daily compounding for an annual rate of 9.3 percent is:
[(1 + 0.093)
] × 365 = 8.894%
1
365 –1
1.093 ENTER 365 ■ 1/x ■ ∧ 1 – 365 x
In theory, however, the frequency could be increased indefinitely, with interest being compounded each hour, or each minute. The limit of this concept is
where the frequency is infinite – that is, “continuous compounding.” The
equivalent interest rate in this case can be shown to be LN(1.093), where LN
is the natural logarithm loge. The number e – approximately 2.7183 – occurs
often in mathematical formulas; ex and logex can both usually be found on
mathematical calculators, sometimes as EXP and LN. Thus:
Continuously compounded rate = LN(1.093) = 8.893%
1.093 ■ MATHS LOG LN
8
1 · Financial Arithmetic Basics
In general:
The continuously compounded interest rate r is:
r=
Calculation
summary
365
days
× LN 1 + i × year where i is the nominal rate for that number of days.
days
(
)
In particular:
r = LN(1 + i) where i is the annual effective rate.
These relationships can be reversed to give:
i=
(
)
days
year
r×
× e 365 – 1
days
Calculation
summary
Example 1.4
The 91-day interest rate is 6.4%. What is the continuously compounded equivalent?
r=
=
365
× LN(1 + i × days
year )
days
365
91
× LN(1 + 0.064 × 365
) = 6.35%
91
.064 ENTER 91 × 365 ÷ 1 + ■ MATH LOGS LN 365 × 91 ÷
Example 1.5
The continuously compounded rate is 7.2%. What is the effective rate?
i = er – 1 = e0.072 – 1 = 7.47%
.072 ■ MATH LOGS EXP 1 –
Reinvestment rates
The assumption we have used so far for compounding interest rates, calculating effective rates, etc. is that interest cashflows arising during an investment
can be reinvested at the same original rate of interest. Although these calculations are very important and useful, reinvestment of such cashflows is in
practice likely to be at different rates.
To calculate the accumulated value by the end of the investment in this case,
account must be taken of the different rate paid on the interim cashflows.
9
Part 1 · The Basics
Example 1.6
£100 is invested for 3 years at 3.5% (paid annually). By the end of the first year,
interest rates for all periods have risen to 4.0% (paid annually). By the end of the
second year, rates have risen to 5.0% (paid annually). Whenever an interest payment is received, it is reinvested to the end of the 3-year period. What is the total
cash returned by the end of the third year?
The cashflows received from the original investment are:
1 year: + £3.50
2 years: + £3.50
3 years: + £103.50
At the end of year 1, the £3.50 is reinvested at 4.0% to produce the following cashflows:
2 years: + £3.50 x 4% = £0.14
3 years: + £3.50 x (1 + 4%) = £3.64
At the end of year 2, the £3.50 from the original investment plus the £0.14 arising
from reinvestment of the first year’s interest, is reinvested at 5.0% to produce the
following cashflow:
3 years: + £3.64 x (1 + 5%) = £3.82
The total return is therefore £103.50 + £3.64 + £3.82 = £110.96
Note that the result would be slightly different if the interim interest payments were
each reinvested only for one year at a time (and then rolled over), rather than reinvested to the maturity of the original investment.
3.5 ENTER .04 x
3.5 +
.05 ENTER 1 + x
.04 ENTER 1 + 3.5 x +
103.5 +
NOMINAL AND EFFECTIVE RATES
We have seen that there are three different elements to any interest rate.
Confusion arises because the words used to describe each element can be
the same.
1. The period for which the investment/loan will last
In this sense, a “6-month” interest rate is one for an investment which lasts six
months and a “1-year” interest rate is one for an investment which lasts one year.
2. The absolute period to which the quoted interest rate applies
Normally, this period is always assumed to be one year, regardless of the
actual period of investment. Thus, if the interest rate on a 6-month invest10
1 · Financial Arithmetic Basics
ment is quoted as 10 percent, this does not mean that the investor in fact
receives 10 percent after six months; rather, the investor receives only 5 percent, because the quoted rate is expressed as the 1-year simple equivalent
rate, even though there is no intention to hold the investment for a year.
Similarly, a 5-year zero-coupon rate of 10 percent means that the investor
will in fact receive 61.05 percent after five years. Again, the quoted rate is the
decompounded one-year equivalent, even though the investment is fixed for
five years and pays no actual interest at the end of one year.
The reason for this “annualizing” of interest rates is to make them
approximately comparable. If this were not done, one would not be able
immediately to compare rates quoted for different periods. Instead, we would
be trying to compare rates such as 0.0274 percent for 1 day, 5 percent for 6
months and 61.05 percent for 5 years (all in fact quoted as 10 percent). A
yield curve drawn like this would be difficult to interpret at a glance.
One exception is the interest paid on personal credit cards, which is sometimes quoted for a monthly period rather than annualized (for cosmetic
reasons). In the UK, for example, credit card companies are obliged also to
quote the effective rate (known as APR, annualized percentage rate).
3. The frequency with which interest is paid
If interest on a 1-year deposit is paid each 6 months, the total interest accumulated at the end of the year, assuming reinvestment of the interim interest
payment, will be greater than the interest accumulated if the deposit pays the
same quoted rate, but all in one amount at the end of the year. When the
interest rate on a money market investment is quoted, it is generally quoted
on the basis of the frequency which the investment does actually have. For
example, if a 1-year deposit pays 2.5 percent each 3 months, the interest is
quoted as 10 percent; the rate is quoted on the basis that all parties know the
payment frequency is 3 months. Similarly, if a 1-year deposit pays 5 percent
each 6 months, or 10 percent at the end, the rate is quoted as 10 percent on
the basis that all parties know the payment frequency is 6 months, or 1 year.
The economic effect is different in each case, but no adjustment is made to
make the quotations comparable; they are simply stated as “10 percent quarterly” or “10 percent semi-annual” or “10 percent annual.”
Yields for financial instruments are generally quoted in the market in this
simple way, regardless of whether they are short-term money market instruments such as treasury bills and deposits, or long-term capital markets
instruments such as bonds and swaps. One exception is zero-coupon rates,
where the interest rate is compounded downwards when expressed as an
annualized rate. Other exceptions may arise in specific markets – for example
treasury bills in Norway are quoted on the basis of an effective annual equivalent yield. Furthermore, because an investor does need to be able to
compare rates, they are often all converted by the investor to a common
effective basis. In this way, “10 percent quarterly” is converted to an effective “10.38 annual equivalent”, or “10 percent annual” to an effective “9.65
percent quarterly equivalent” or “9.532 percent daily equivalent”.
11
Part 1 · The Basics
FUTURE VALUE / PRESENT VALUE; TIME VALUE OF MONEY
This section is probably the most important in this book, as present value
calculations are the key to pricing financial instruments.
Short-term investments
If I deposit 100 for 1 year at 10 percent per annum, I receive:
100 × (1 + 0.10 ) = 110
at the end of the year. In this case, 110 is said to be the “future value” (or
“accumulated value”) after 1 year of 100 now. In reverse, 100 is said to be
the “present value” of 110 in a year’s time. Future and present values clearly
depend on both the interest rate used and the length of time involved.
Similarly, the future value after 98 days of £100 now at 10 percent per
annum would be 100 × (1 + 0.10 × —
´oi¥†).
The expression above can be turned upside down, so that the present
value now of 102.68 in 98 days’ time, using 10 percent per annum, is:
102.68
oi¥†)
(1 + 0.10 × ´—
= 100
In general, the present value of a cashflow C, using an interest rate i is:
C
(1 + i × days
year )
We can therefore now generate a future value from a present value, and vice
versa, given the number of days and the interest rate. The third calculation
needed is the answer to the question: if we know how much money we invest at
the beginning (= the present value) and we know the total amount at the end (=
the future value), what is our rate of return, or yield (= the interest rate) on the
investment? This is found by turning round the formula above again, to give:
yield =
(
)
future value
year
–1 ×
present value
days
This gives the yield as normally expressed – that is, the yield for the period of the
investment. This can of course then be converted to an effective rate by using:
(
effective yield = 1 + i ×
days
year
365
days
)
–1
Combining these two relationships gives:
effective yield =
12
(
future value
present value
365
days
)
–1
1 · Financial Arithmetic Basics
The calculation of present value is sometimes known as “discounting” a
future value to a present value and the interest rate used is sometimes known
as the “rate of discount.”
In general, these calculations demonstrate the fundamental principles
behind market calculations, the “time value of money.” As long as interest
rates are not negative, any given amount of money is worth more sooner
than it is later because if you have it sooner, you can place it on deposit to
earn interest. The extent to which it is worthwhile having the money sooner
depends on the interest rate and the time period involved.
Calculation
summary
For short-term investments
(
FV = PV × 1 + i ×
PV =
i=
days
year
)
FV
(1 + i × )
days
year
year
– 1) ×
( FV
PV
days
( )
FV
effective yield (annual equivalent) =
PV
365
days
–1
Long-term investments
The formulas above are for investments where no compound interest is
involved. For periods more than a year where compounding is involved, this
compounding must be taken into account.
The future value in three years’ time of 100 now, using 10 percent per
annum is:
100 × (1 + 0.10)3 = 133.10
This expression can again be turned upside down, so that the present value
now of 133.10 in three years’ time, using 10 percent per annum, is:
133.10
= 100
(1 + 0.10)3
In general, the present value of a cashflow C in N years’ time, using an interest rate i, is:
C
(1 + i)N
13
Part 1 · The Basics
Calculation
summary
For long-term investments over N years
FV = PV × (1 + i)N
PV =
i=
FV
(1 + i)N
1
N
( ) –1
FV
PV
Example 1.7
What is the future value in 5 years’ time of £120 now, using 8% per annum?
120 × (1.08)5 = 176.32
(The interest rate is compounded because interest is paid each year and can
be reinvested)
Answer: £176.32
1.08 ENTER
5■∧
120 x
Example 1.8
What is the future value in 92 days’ time of £120 now, using 8% per annum?
(
120 × 1 + 0.08 ×
92
= 122.42
365
)
(Simple interest rate, because there is only one interest payment, at maturity)
Answer: £122.42
.08 ENTER
92 × 365 ÷
1 + 120 x
Example 1.9
What is the present value of £270 in 4 years’ time, using 7% per annum?
270
= 205.98
(1.07)4
(The interest rate is compounded because interest is paid each year and can
be reinvested)
Answer: £205.98
14
1 · Financial Arithmetic Basics
1.07 ENTER
4■^
270 ■ xy ÷
Example 1.10
What is the present value of £270 in 180 days’ time, using 7% per annum?
270
180
(1 + 0.07 × 365
)
= 260.99
(Simple interest rate, because there is only one interest payment, at maturity)
Answer: £260.99
.07 ENTER
180 × 365 ÷
1+
270 ■ xy ÷
Example 1.11
I invest £138 now. After 64 days I receive back a total (principal plus interest) of
£139.58. What is my yield on this investment?
yield =
365
–1) ×
= 0.0653
( 139.58
138.00
64
Answer: 6.53%
139.58 ENTER
138 ÷
1–
365 ×
64 ÷
DISCOUNT FACTORS
So far, we have discounted from a future value to a present value by dividing
by (1 + i × days
) for simple interest and (1+i)N for compound interest. An alteryear
native way of expressing this, also commonly used, is to multiply by the
reciprocal of these numbers, which are then usually called “discount factors.”
15
Part 1 · The Basics
Example 1. 12
What is the 92-day discount factor if the interest rate for the period is 7.8%? What
is the present value of £100 in 92 days’ time?
discount factor =
1
1 + 0.078 ×
92
365
= 0.9807
£100 x 0.9807 = £98.07
.078 ENTER 92 × 365 ÷ 1 + ■ 1/x
100 ×
(Discount factor)
(Present value)
Example 1.13
What is the 3-year discount factor based on a 3-year interest rate of 8.5% compounded annually? What is the present value of £100 in 3 years’ time?
discount factor =
1
= 0.7829
(1 + 0.085)3
£100 x 0.7829 = £78.29
1.085 ENTER 3 ■ ∧ ■ 1/x
100 ×
Calculation
summary
(Discount factor)
(Present value)
For simple interest
Discount factor =
1
1 + i × days
year
For compound interest
Discount factor =
(1 1+ i )
N
Note that we know from an earlier section that using a continuously compdays
year
pounded interest rate r, i =
× (er × 365 –1).
days
Using a continuously compounded interest rate therefore, the discount factor
becomes:
days
1
1
–r × 365
=
=e
days
days
1 + i × year 1 + (e r × 365 –1)
This way of expressing the discount factor is used commonly in option pricing
formulas.
Calculation
summary
Using a continuously compounded interest rate
days
Discount factor = e –r × 365
16
1 · Financial Arithmetic Basics
CASHFLOW ANALYSIS
NPV
Suppose that we have a series of future cashflows, some of which are positive
and some negative. Each will have a present value, dependent on the time to
the cashflow and the interest rate used. The sum of all the positive and negative present values added together is the net present value or NPV.
Example 1.14
What is the NPV of the following future cashflows, discounting at a rate of 7.5%?
After 1 year:
After 2 years:
After 3 years:
+ $83
– $10
+$150
83
10
150
–
+
= 189.30
2
(1.075) (1.075)
(1.075)3
Answer: +$189.30
83 ENTER 1.075 ÷
10 ENTER 1.075 ENTER 2 ■ ∧ ÷ –
150 ENTER 1.075 ENTER 3 ■ ∧ ÷ +
NPV = sum of all the present values
Key Point
IRR
An internal rate of return (IRR) is the one single interest rate which it is necessary to use when discounting a series of future values to achieve a given net
present value. This is equivalent to the interest rate which it is necessary to
use when discounting a series of future values and a cashflow now, to
achieve a zero present value. Suppose the following cashflows, for example,
which might arise from some project:
Now:
After 1 year:
After 2 years:
After 3 years:
After 4 years:
– 87
+ 25
– 40
+ 60
+ 60
What interest rate is needed to discount +25, –40, +60 and +60 back to a net
present value of +87? The answer is 5.6 percent. It can therefore be said that
an initial investment of 87 produces a 5.6 percent internal rate of return if it
17
Part 1 · The Basics
generates these subsequent cashflows. This is equivalent to saying that, using
5.6 percent, the net present value of –87, +25, –40, +60 and +60 is zero.
Calculating a NPV is relatively simple: calculate each present value separately and add them together. Calculating an IRR however requires a
repeated “trial and error” method and is therefore generally done using a
specially designed calculator.
Example 1.15
What is the IRR of the following cashflows?
Now:
After 1 year:
After 2 years:
After 3 years:
–$164
+$45
+$83
+$75
Answer: 10.59% (If you do not have a calculator able to calculate this, try checking
the answer by working backwards: the NPV of all the future values, using the rate
of 10.59%, should come to + $164).
See below for an explanation of how to use the HP19 to solve this.
Key Point
The internal rate of return is the interest rate which discounts all the
known future cashflows to a given NPV.
This is equivalent to the interest rate which discounts all the cashflows
including any cashflow now to zero.
Annuity
An annuity is a regular stream of future cash receipts which can be purchased by an initial cash investment. The size of the future cash receipts is
determined by the yield which can be obtained on the investment. In other
words, the internal rate of return of the cashflows (initial outflow and subsequent inflows) is the yield.
Example 1.16
An investor puts £50,000 in a 20-year annuity, yielding 7.2%. The annuity returns
an equal cash amount at the end of each year, with no additional amount at maturity. What is the annual cash amount?
Answer: £4,793.26. (If you do not have a calculator able to calculate this, you can
check the answer by working backwards: the NPV at 7.2% of £4,793.26 each year
for 20 years is £50,000.)
See below for an explanation of how to use the HP19 to solve this.
18
1 · Financial Arithmetic Basics
Using an HP calculator
There are various functions built into the HP calculator relating to the time
value of money. These involve using five keys: N for the number of time periods involved, I%YR for the yield, PV for the initial cashflow or present value,
PMT for a regular cashflow recurring at the end of each period and FV for an
additional final cashflow or the future value. Any of the cashflows (PV, PMT,
or FV) may be zero. Before any cashflow operation, we suggest setting the calculator by entering g END (for the HP12C) or selecting the FIN menu,
selecting the TVM menu, selecting OTHER and then selecting END (for the
other calculators). Note that you must always pay strict attention to the sign of
each cashflow: a cash outflow is negative and a cash inflow is positive.
HP calculator example
What is the net present value of the following cashflows using an interest rate of 10%?
$11 at the end of each year for 7 years.
$80 at the end of the seventh year in addition to the $11.
Answer: $94.61
HP12C
7n
10 i
11 PMT
80 FV
PV
HP19BII (RPN mode)
Select FIN menu
Select TVM menu
7N
10 I%YR
11 PMT
80 FV
PV
HP19BII (algebraic)
Select FIN menu
Select TVM menu
7N
10 I%YR
11 PMT
80 FV
PV
HP calculator example
What is the internal rate of return of the following cashflows?
Outflow of $94.6053 now.
Inflow of $11 at the end of each year for seven years.
Inflow of $80 at the end of the seventh year in addition to the $11.
Answer: 10%
HP12C
7n
94.6053 CHS PV
11 PMT
80 FV
i
HP19BII (RPN mode)
Select FIN menu
Select TVM menu
7N
94.6053 +/- PV
11 PMT
80 FV
I%YR
HP19BII (algebraic)
Select FIN menu
Select TVM menu
7N
94.6053 +/- PV
11 PMT
80 FV
I%YR
19
Part 1 · The Basics
HP calculator example
What regular cash inflow is needed at the end of each year for the next seven years
to achieve an internal rate of return of 10%, assuming an additional final cash
inflow of $80 at the end of the seventh year and a net present value of $94.6053?
Answer: $11
HP12C
7n
10 i
94.6053 CHS PV
80 FV
PMT
HP19BII (RPN mode)
Select FIN menu
Select TVM menu
7N
10 I%YR
94.6053 +/- PV
80 FV
PMT
HP19BII (algebraic)
Select FIN menu
Select TVM menu
7N
10 I%YR
94.6053 +/- PV
80 FV
PMT
You can see that the last three examples all involve the same five data: the
number of time periods (N = 7), the interest rate or internal rate of return per
period (I%YR = 10), the net present value (PV = -94.6053), the regular cashflow each period (PMT = 11) and the additional final cashflow or future
value (FV = 80). Once four of these five data have been entered, the fifth can
be calculated by pressing the relevant key.
HP calculator example
What is the internal rate of return of the following cashflows?
Outflow of $60 now.
Inflow of $10 at the end of each year for 10 years.
Answer: 10.5580%
HP12C
10 n
60 CHS PV
10 PMT
0 FV
i
HP19BII (RPN mode)
Select FIN menu
Select TVM menu
10 N
60 +/- PV
10 PMT
0 FV
I%YR
HP19BII (algebraic)
Select FIN menu
Select TVM menu
10 N
60 +/- PV
10 PMT
0 FV
I%YR
For the TVM function to be appropriate, the time periods between each
cashflow must be regular. They do not need to be 1 year. If the periods are
shorter than a year however, the absolute interest rate for that period and the
total number of periods (rather than years) must be entered.
20
1 · Financial Arithmetic Basics
HP calculator example
What is the net present value of the following cashflows using an interest rate of
10% per annum paid quarterly?
$100 at the end of each quarter for 5 years.
$1,000 at the end of the fifth year in addition to the $100.
HP12C
20 n
2.5 i
100 PMT
1000 FV
PV
HP19BII (RPN mode)
HP19BII (algebraic)
Select FIN menu
Select TVM menu
20 N
2.5 I%YR
100 PMT
1000 FV
Select FIN menu
Select TVM menu
20 N
2.5 I%YR
100 PMT
1000 FV
PV
PV
Answer: $2,169.19
In the example above, instead of entering the interest rate per period as
2.5 percent, it is possible with the HP19BII to enter the interest rate per year
HP19BII (RPN mode)
Select FIN menu
Select TVM menu
OTHER 4 P/YR EXIT
20 N
10 I%YR
100 PMT
1000 FV
PV
HP19BII (algebraic)
Select FIN menu
Select TVM menu
OTHER 4 P/YR EXIT
20 N
10 I%YR
100 PMT
1000 FV
PV
as 10 percent and the number of payments per year as 4 as follows. This
merely avoids dividing by 4.
The built-in TVM functions can be used when all the cashflows are the same
except for the initial cashflow now or present value, and the additional final
cashflow or future value. For bonds and swaps, this is often the case. In cases
where the cashflows are irregular however, an alternative function must be used.
21
Part 1 · The Basics
HP calculator example
What is the IRR of the following cashflows?
Now:
After 1 year:
After 2 years:
After 3 years:
After 4 years:
After 5 years:
After 6 years:
After 7 years:
–$120
+$20
+$90
–$10
+$30
+$30
+$30
+$40
Answer: 20.35%
HP12C
f CLEAR REG
120 CHS g CFo
20 g Cfj
90 g Cfj
10 CHS g Cfj
30 g Cfj
3 g Nj
40 g Cfj
f IRR
HP19BII (RPN mode)
Select FIN menu
Select CFLO menu
GET NEW
120 +/- INPUT
20 INPUT INPUT
90 INPUT INPUT
10 +/- INPUT INPUT
30 INPUT 3 INPUT
40 INPUT INPUT
CALC
IRR%
*
HP19BII (algebraic)
Select FIN menu
Select CFLO menu
GET NEW
120 +/- INPUT
20 INPUT INPUT
90 INPUT INPUT
10 +/- INPUT INPUT
30 INPUT 3 INPUT
40 INPUT INPUT
CALC
IRR%
*
(If several successive cashflows are the same, the amount need be entered
only once, followed by the number of times it occurs.)
HP calculator example
Using the same cashflows as above, what is the NPV of all the cashflows using an
interest rate of 10%?
Answer: 41.63%
HP12C
f CLEAR REG
120 CHS g Cfo
20 g Cfj
90 g Cfj
10 CHS g Cfj
30 g Cfj
3 g Nj
40 g Cfj
10 i
f NPV
22
HP19BII (RPN mode)
Select FIN menu
Select CFLO menu
GET NEW
120 +/- INPUT
20 INPUT INPUT
90 INPUT INPUT
10 +/- INPUT INPUT
30 INPUT 3 INPUT
40 INPUT INPUT
CALC
10 I%
NPV
*
HP19BII (algebraic)
Select FIN menu
Select CFLO menu
GET NEW
120 +/- INPUT
20 INPUT INPUT
90 INPUT INPUT
10 +/- INPUT INPUT
30 INPUT 3 INPUT
40 INPUT INPUT
CALC
10 I%
NPV
*
1 · Financial Arithmetic Basics
Solution to Example 1.15 using HP19BII
FIN CFLO GET NEW
164 +/- INPUT
45 INPUT INPUT
83 INPUT INPUT
75 INPUT INPUT
CALC
IRR%
*
Solution to Example 1.16 using HP19BII
FIN TVM
20 N
7.2 I%YR
50,000 +/- PV
0 FV
PMT
INTERPOLATION AND EXTRAPOLATION
In the money market, prices are generally quoted for standard periods such
as 1 month, 2 months, etc. If a dealer needs to quote a price for an “odd
date” between these periods, he needs to “interpolate.”
Suppose for example that the 1-month rate (30 days) is 8.0 percent and
that the 2-month rate (61 days) is 8.5 percent. The rate for 1 month and
9 days (39 days) assumes that interest rates increase steadily from the 1month rate to the 2-month rate – a straight line interpolation. The increase
from 30 days to 39 days will therefore be a _
´oœ proportion of the increase
from 30 days to 61 days. The 39-day rate is therefore:
8.0% + (8.5% – 8.0%) × ´_oœ = 8.15%
The same process can be used for interpolating exchange rates.
Example 1.17
The 2-month (61 days) rate is 7.5% and the 3-month (92 days) rate is 7.6%.
What is the 73-day rate?
7.5 + (7.6 – 7.5) × 12
= 7.5387
31
Answer: 7.5387%
7.6 ENTER 7.5 –
12 x 31 ÷
7.5 +
23
Part 1 · The Basics
If the odd date required is just before or just after the known periods, rather
than between them, the same principle can be applied (in this case “extrapolation” rather than interpolation).
Example 1.18
The 2-month (61 days) rate is 7.5% and the 3-month (92 days) rate is 7.6%.
What is the 93-day rate?
7.5 + (7.6 – 7.5) × 32
= 7.6032
31
Answer: 7.6032%
7.6 ENTER 7.5 –
32 x 31 ÷
7.5 +
Calculation
summary
i = i1 + (i2 – i1) ×
where: i is the rate required for d days
i1 is the known rate for d1 days
i2 is the known rate for d2 days.
24
(d – d1)
(d2 –d1)
1 · Financial Arithmetic Basics
EXERCISES
1. What is the future value after 120 days of £43 invested at 7.5%?
2. You will receive a total of £89 after 93 days. What is the present value of this
amount discounted at 10.1%?
3. You invest £83 now and receive a total of £83.64 back after 28 days. What is
the yield on your investment?
4. What is the future value in 10 years’ time of £36 now, using 9% per annum?
5. You have a choice between receiving DEM 1,000 now or DEM 990 in
3 months’ time. Assuming interest rates of 8.0%, which do you choose?
6. If you invest £342 for 5 years at 6% per annum (interest paid annually), how
much interest do you receive at the end of 5 years assuming that all interim
cashflows can be reinvested also at 6%?
7. What is the present value, using a rate of discount of 11%, of a cashflow of
DEM 98.00 in 5 years’ time?
8. You place £1,000 in a 4-year investment which makes no interest payments
but yields 5.4% per annum compound. How much do you expect to receive at
the end of 4 years?
9. You invest £1,000 and receive back a total of £1,360.86 at the end of 7 years.
There are no interest payments during the 7 years. What annual yield does
this represent?
10. You deposit £1 million for 10 years. It accumulates interest at 6% quarterly for
the first 5 years and 6.5% semi-annually for the next five years. The interest is
automatically added to the capital at each payment date. What is the total
accumulated value at the end of 10 years?
11. You place £1 million on deposit for 1 year at 8.5%. What total value will you
have accumulated by the end of the year, assuming that the interest is paid
quarterly and can be reinvested at the same rate? What would the total value
be if the interest payments could be reinvested at only 8.0% paid quarterly?
12. You buy a 10-year annuity, with a yield of 9% per annum. How much must you
invest in the annuity now to receive £5,000 at the end of each year?
13. You borrow £90,000 for 25 years at 7.25% per annum (interest paid
monthly). You repay the loan by making equal payments which cover principal plus interest at the end of each month for the 25 years. How much are
the monthly payments?
25
Part 1 · The Basics
14. You receive 11.4% paid semi-annually. What is the effective rate (annual
equivalent)?
15. You receive 12% paid annually. What are the equivalent quarterly rate and
monthly rate?
16. If 7.0% is a continuously compounded interest rate, what is the total value accumulated at the end of a year at this rate, on a principal amount of £1 million, and
what is the effective rate (annual equivalent)? If 9.0% is an effective (annual
equivalent) rate, what is the equivalent continuously compounded rate?
17. You receive 6.5% per annum on a 138-day deposit. What is the effective rate?
What is the daily equivalent rate? What is the 138-day discount factor?
18. The 30-day interest rate is 5.2% and the 60-day rate is 5.4%. Interpolate to
find the 41-day rate.
19. What is the NPV of the following cashflows using an effective annual interest
rate of 10% per annum?
Now
6 months
12 months
18 months
24 months
36 months
–$105
–$47
–$47
–$47
–$93
+$450
20. What is the IRR of the cashflows in the previous question?
26
Part 2
Interest Rate
Instruments
27
■
■
■
“For any instrument, the price
an investor is prepared to pay is
the present value of the future
cashflows which he or she will
receive because of owning it.”
28
2
The Money Market
Overview
Day/year conventions
Money market instruments
Money market calculations
Discount instruments
CDs paying more than one coupon
Exercises
29
Part 2 · Interest Rate Instruments
OVERVIEW
The “money market” is the term used to include all short-term financial
instruments which are based on an interest rate (whether the interest rate is
actually paid or just implied in the way the instrument is priced).
The underlying instruments are essentially those used by one party (borrower, seller or issuer) to borrow and by the other party to lend (the lender,
buyer or investor). The main such instruments are:
•
•
•
•
Treasury bill
Time deposit
Certificate of deposit (CD)
Commercial paper (CP)
• Bill of exchange
– borrowing by government.
}
borrowing by banks.
– borrowing by companies (or in some
cases, banks).
– borrowing by companies.
Each of these instruments represents an obligation on the borrower to repay
the amount borrowed at maturity, plus interest if appropriate. As well as
these underlying borrowing instruments, there are other money market
instruments which are linked to these, or at least to the same interest rate
structure, but which are not direct obligations on the issuer in the same way:
• Repurchase agreement
•
•
– used to borrow short-term but using
another instrument (such as a bond)
as collateral.
Futures contract
used to trade or hedge short-term
Forward rate agreement (FRA)
interest rates for future periods.
}
The money market is linked to other markets through arbitrage mechanisms. Arbitrage occurs when it is possible to achieve the same result in
terms of position and risk through two alternative mechanisms which have
a slightly different price; the arbitrage involves achieving the result via the
cheaper method and simultaneously reversing the position via the more
expensive method – thereby locking in a profit which is free from market
risk (although still probably subject to credit risk). For example, if I can
buy one instrument cheaply and simultaneously sell at a higher price
another instrument or combination of instruments which has identical
characteristics, I am arbitraging. In a completely free market with no other
price considerations involved, the supply and demand effect of arbitrage
tends to drive the two prices together.
For example, the money market is linked in this way to the forward foreign exchange market, through the theoretical ability to create synthetic
deposits in one currency, by using foreign exchange deals combined with
money market instruments. Similarly, it is linked to the capital markets
(long-term financial instruments) through the ability to create longer-term
instruments from a series of short-term instruments (such as a 2-year swap
from a series of 3-month FRAs).
30
2 · The Money Market
Eurocurrency Historically, the term “Euro” has been used to describe any
instrument which is held outside the country whose currency is involved.
The term does not imply “European” specifically. For example, a sterling deposit made by a UK resident in London is domestic sterling, but a
sterling deposit made in New York is Eurosterling. Similarly, US dollar
commercial paper issued outside the USA is Eurocommercial paper while
US dollar commercial paper issued inside the USA is domestic commercial paper. Confusingly, this term has nothing whatever to do with the
proposed European Union currency also called “euro.”
Terminology
Coupon / yield A certificate of deposit pays interest at maturity as well as
repaying the principal. For example, a CD might be issued with a face
value of £1 million which is repaid on maturity together with interest of,
say, 10 percent calculated on the number of days between issue and
maturity. The 10 percent interest rate is called the “coupon.” The
coupon is fixed once the CD is issued. This should not be confused with
the “yield,” which is the current rate available in the market when
buying and selling an instrument, and varies continually.
Discount 1. An instrument which does not carry a coupon is a “discount”
instrument. Because there is no interest paid on the principal, a buyer will
only ever buy it for less than its face value – that is “at a discount” (unless
yields are negative!). For example, all treasury bills are discount instruments.
2. The word “discount” is also used in the very specialized context of
a “discount rate” quoted in the US and UK markets on certain instruments. This is explained in detail below.
Bearer / registered A “bearer” security is one where the issuer pays the principal (and coupon if there is one) to whoever is holding the security at
maturity. This enables the security to be held anonymously. A “registered” security, by contrast, is one where the owner is considered to be
whoever is registered centrally as the owner; this registration is changed
each time the security changes hands.
▼
LIBOR “LIBOR” means “London interbank offered rate” – the interest
rate at which one London bank offers money to another London bank
of top creditworthiness as a cash deposit. LIBID means “London interbank bid rate” – the interest rate at which one London bank of top
creditworthiness bids for money as a cash deposit from another. LIBOR
is therefore always the higher side of a two-sided interest rate quotation
(which is quoted high–low in some markets and low–high in others).
LIMEAN is the average between the two sides. In practice, the offered
rate for a particular currency at any moment is generally no different in
London from any other major centre. LIBOR is therefore often just
shorthand for “offered interest rate.”
Specifically, however, LIBOR also means the average offered rate
quoted by a group of banks at a particular time (in London, usually
11:00 am) for a particular currency, which can be used as a benchmark
31
Part 2 · Interest Rate Instruments
for agreeing rates between two parties. Similarly, PIBOR refers specifically to the interbank offered rate in Paris for French francs; STIBOR to
the interbank offered rate in Stockholm for Swedish kronor; FIBOR in
Frankfurt for Deutschemarks, etc.
DAY/YEAR CONVENTIONS
As a general rule in the money markets, the calculation of interest takes
account of the exact numbers of days in the period in question, as a proportion of a year. Thus:
Key Point
Interest paid = interest rate quoted × days in period/days in year
A variation between different money markets arises, however, in the conventions used for the number of days assumed to be in the base “year.”
Domestic UK instruments, for example, assume that there are 365 days in a
year, even when it is a leap year. Thus a sterling time deposit at 10 percent
which lasts exactly one year, but includes 29 February in its period (a total of
366 days), will actually pay slightly more than 10 percent – in fact:
10% × 366 = 10.027%
365
This convention is usually referred to as ACT/365 – that is, the actual number
of days in the period concerned, divided by 365. Some money markets, however, assume that each year has a conventional 360 days. For example, a dollar
time deposit at 10 percent which lasts exactly 365 days pays:
10% × 365 = 10.139%
360
This convention is usually referred to as ACT/360. Most money markets
assume a conventional year of 360 days. There are, however, some exceptions, which assume a year of 365 days. These include the Euromarkets and
domestic markets in the following currencies:
•
•
•
•
•
•
32
Sterling
Irish pound
Belgian / Luxembourg franc
Portuguese escudo
Greek drachma
Hong Kong dollar
2 · The Money Market
•
•
•
•
•
Singapore dollar
Malaysian ringgit
Taiwan dollar
Thai baht
South African rand
and the domestic (but not Euro) markets in the following currencies:
•
•
•
•
•
•
Japanese yen
Canadian dollar
Australian dollar
New Zealand dollar
Italian lira
Finnish markka
In order to convert an interest rate i quoted on a 360-day basis to an interest
rate i* quoted on a 365-day basis:
i* = i ×
365
360
Similarly,
i* = i ×
360
365
360
Interest rate on 360-day basis = interest rate on 365-day basis × ---=
365
Calculation
summary
365
Interest rate on 365-day basis = interest rate on 360-day basis × --360
Example 2.1
The yield on a security on an ACT/360 basis is 10.5%. What is the equivalent yield
expressed on an ACT/365 day basis?
10.5 ×
365
= 10.6458
360
Answer: 10.6458%
10.5 ENTER
365 × 360 ÷
There are some exceptions to the general approach above. Yields on Swedish
T-bills and some short-term German securities, for example, are calculated in
the same way as Eurobonds (discussed in Chapter 5).
We have given a list of the conventions used in some important markets in
Appendix 2.
33
Part 2 · Interest Rate Instruments
Effective rates
The concept of “effective rate” discussed in Chapter 1 normally implies an
annual equivalent interest rate on the basis of a calendar year – that is, 365
days. It is possible however to convert the result then to a 360-day basis.
Example 2.2
An amount of 83 is invested for 214 days. The total proceeds at the end are 92.
What are the simple and effective rates of return on an ACT/360 basis?
Simple rate of return (ACT/360) =
total proceeds
year
– 1) ×
( initial
investment
days
360
–1 ×
= 18.24%
( 92
83 ) 214
total proceeds
Effective rate of return (ACT/365) = (
initial investment )
92
=(
–1 = 19.19%
83 )
=
365
days
–1
365
214
Effective rate of return (ACT/360) = 19.19% ×
92 ENTER 83 ÷ 1 – 360 × 214 ÷
92 ENTER 83 ÷ 365 ENTER 214 ÷ ■ ∧ 1 –
360 × 365 ÷
360
= 18.93%
365
(Simple rate ACT/360)
(Effective rate ACT/360)
92
Note that in Example 2.2 the effective rate on an ACT/360 basis is not
83
= 18.91%.
360
214
( )
–1
This would instead be the equivalent 360-day rate (ACT/360 basis) – that is,
the rate on a 360-day investment which is equivalent on a compound basis to
18.24 percent on a 214-day investment. The effective rate we want instead is
the equivalent 365-day rate (ACT/360 basis) – that is, the rate on a 365-day
investment which is equivalent on a compound basis to 18.24 percent
(ACT/360) on a 214-day investment. The difference between these two is
however usually not very significant.
MONEY MARKET INSTRUMENTS
Time deposit / loan
A time deposit or “clean” deposit is a deposit placed with a bank. This is not
a security which can be bought or sold (that is, it is not “negotiable”), and it
must normally be held to maturity.
34
2 · The Money Market
term
interest
from one day to several years, but usually less than one year
usually all paid on maturity, but deposits of over a year
(and sometimes those of less than a year) pay interest more
frequently – commonly each six months or each year. A
sterling 18-month deposit, for example, generally pays
interest at the end of one year and then at maturity.
quotation as an interest rate
currency
any domestic or Eurocurrency
settlement generally same day for domestic, two working days for
Eurocurrency
registration there is no registration
negotiable no
Certificate of deposit (CD)
A CD is a security issued to a depositor by a bank or building society, to
raise money in the same way as a time deposit. A CD can however be bought
and sold (that is, it is “negotiable”).
term
generally up to one year, although longer-term CDs are
issued
interest
usually pay a coupon, although occasionally sold as a discount instrument. Interest usually all paid on maturity, but
CDs of over a year (and sometimes those of less than a year)
pay interest more frequently – commonly each six months or
each year. Some CDs pay a “floating” rate (FRCD), which is
paid and refixed at regular intervals.
quotation as a yield
currency
any domestic or Eurocurrency
settlement generally same day for domestic, two working days for
Eurocurrency
registration usually in bearer form
negotiable yes
Treasury bill (T-bill)
Treasury bills are domestic instruments issued by governments to raise shortterm finance.
35
Part 2 · Interest Rate Instruments
term
generally 13, 26 or 52 weeks; in France also 4 to 7 weeks;
in the UK generally 13 weeks
interest
in most countries non-coupon bearing, issued at a discount
quotation in USA and UK, quoted on a “discount rate” basis, but in
most places on a true yield basis
currency
usually the currency of the country; however the UK and
Italian governments, for example, also issue ECU T-bills
registration bearer security
negotiable yes
Commercial paper (CP)
CP is issued usually by a company (although some banks also issue CP) in
the same way that a CD is issued by a bank. CP is usually, however, not
interest-bearing. A company generally needs to have a rating from a credit
agency for its CP to be widely acceptable. Details vary between markets.
US CP
term
interest
quotation
currency
settlement
registration
negotiable
from one day to 270 days; usually very short-term
non-interest bearing, issued at a discount
on a “discount rate” basis
domestic US$
same day
in bearer form
yes
Eurocommercial Paper (ECP)
term
interest
quotation
from two to 365 days; usually between 30 and 180 days
usually non-interest bearing, issued at a discount
as a yield, calculated on the same year basis as other money
market instruments in that Eurocurrency
currency
any Eurocurrency but largely US$
settlement two working days
registration in bearer form
negotiable yes
36
2 · The Money Market
Bill of exchange
A bill of exchange is used by a company essentially for trade purposes. The
party owing the money is the “drawer” of the bill. If a bank stands as guarantor to the drawer, it is said to “accept” the bill by endorsing it
appropriately, and is the “acceptor”. A bill accepted in this way is a
“banker’s acceptance” (BA). In the UK, if the bank is one on a specific list of
banks published by the Bank of England, the bill becomes an “eligible bill”
which means it is eligible for discounting by the Bank of England, and will
therefore command a slightly lower yield than an ineligible bill.
term
interest
quotation
from one week to one year but usually less than six months
non-interest bearing, issued at a discount
in USA and UK, quoted on a “discount rate” basis, but
elsewhere on a true yield basis
currency
mostly domestic, although it is possible to draw foreign
currency bills
settlement available for discount immediately on being drawn
registration none
negotiable yes, although in practice banks often tend to hold the bills
they have discounted until maturity
Repurchase agreement (repo)
A repo is an arrangement whereby one party sells a security to another party
and simultaneously agrees to repurchase the same security at a subsequent
date at an agreed price. This is equivalent to the first party borrowing from
the second party against collateral, and the interest rate reflects this – that is,
it is slightly lower than an unsecured loan. The security involved will often
be of high credit quality, such as a government bond. A reverse repurchase
agreement (reverse repo) is the same arrangement viewed from the other
party’s perspective. The deal is generally a “repo” if it is initiated by the
party borrowing money and lending the security and a “reverse repo” if it is
initiated by the party borrowing the security and lending the money.
term
usually very short-term, although in principle can be for
any term
interest
usually implied in the difference between the purchase and
repurchase prices
quotation as a yield
currency
any currency
settlement generally cash against delivery of the security (DVP)
registration n/a
negotiable no
37
Part 2 · Interest Rate Instruments
Repos provide a link between the money markets and the bond markets and
we have considered an example in Chapter 5.
MONEY MARKET CALCULATIONS
For any instrument, the price an investor is prepared to pay is essentially the
present value, or NPV, of the future cashflow(s) which he/she will receive
because of owning it. This present value depends on the interest rate (the
“yield”), the time to the cashflow(s) and the size of the cashflow(s).
Key Point
Price = present value
For an instrument such as a CD which has a coupon rate, the price in the
secondary market will therefore depend not only on the current yield but
also on the coupon rate, because the coupon rate affects the size of the cashflow received at maturity.
Consider first a CD paying only one coupon (or in its last coupon period).
The maturity proceeds of the CD are given by:
(
F × 1 + coupon rate ×
where:
days
year
)
F = face value of the CD
days = number of days in the coupon period
year = either 360 (e.g. in the USA) or 365 (e.g. in the UK).
The price P of this CD now is the investment needed at the current yield i to
achieve this amount on maturity – in other words, the present value now of
the maturity proceeds:
(
F × 1 + coupon rate ×
P=
(
1+i×
dpm
year
)
days
year
)
where: dpm = number of days from purchase to maturity.
The price would normally be quoted based on a face value amount of 100.
38
2 · The Money Market
We saw earlier that the simple return on any investment can be calculated as:
(
)
total proceeds at maturity
year
–1 ×
initial investment
days held
Following this, the yield E earned on a CD purchased after issue and sold
before maturity will be given by:
E=
(
) (
price achieved on sale
year
–1 ×
price achieved on purchase
days held
)
From the previous formula, this is:
E=
[
d
(1 + i × year
) – 1 × year
(days held )
d
(1 + i × year
)
]
pm
p
sm
s
where: ip
is
dpm
dsm
=
=
=
=
yield on purchase
yield on sale
number of days from purchase to maturity
number of days from sale to maturity.
Example 2.3
A CD is issued for $1 million on 17 March for 90 days (maturity 15 June) with a
6.0% coupon. On 10 April the yield is 5.5%. What are the total maturity proceeds?
What is the secondary market price on 10 April?
90
Maturity proceeds = $1 million × ( 1 + 0.06 × 360
) = $1,015,000.00
Price =
$1,015,000.00
66
(1 + 0.055 × 360
)
= $1,004,867.59
On 10 May, the yield has fallen to 5.0%. What is the rate of return earned on holding the CD for the 30 days from 10 April to 10 May?
Return =
[
1 + 0.055 ×
1 + 0.050 ×
66
360
36
360
.06 ENTER 90 × 360 ÷ 1 +
1,000,000 ×
.055 ENTER 66 × 360 ÷ 1 + ÷
.055 ENTER 66 × 360 ÷ 1 +
.05 ENTER 36 × 360 ÷ 1 +
÷
1–
360 × 30 ÷
]
–1 ×
360
= 6.07%
30
(Maturity proceeds)
(Secondary market cost)
(Return over 30 days)
39
Part 2 · Interest Rate Instruments
Calculation
summary
For a CD
(
days from issue
to maturity
Maturity proceeds = face value × 1 + coupon rate ×
year
maturity proceeds
Secondary market price =
(
1 + market yield ×
Return on holding a CD =
)
[
days left to maturity
year
(
1 + purchase yield ×
(
1 + sale yield ×
)
days from purchase
to maturity
year
)
days from sale
to maturity
year
)
]
–1 ×
year
days
held
DISCOUNT INSTRUMENTS
Some instruments are known as “discount” instruments. This means that
only the face value of the instrument is paid on maturity, without a coupon,
in return for a smaller amount paid originally (instead of the face value paid
originally in return for a larger amount on maturity). Treasury bills, for
example, are discount instruments.
Consider, for example, a Belgian treasury bill for BEF 10 million issued
for 91 days. On maturity, the investor receives only the face value of BEF
10 million. If the yield on the bill is 10 percent, the price the investor will be
willing to pay now for the bill is its present value calculated at 10 percent:
Price =
BEF 10 million
91
(1 + 0.10 × 365
)
= BEF 9,756,749.53
Example 2.4
A French T-bill with face value FRF 10 million matures in 74 days. It is quoted at
8.4%. What is the price of the bill?
FRF 10 million
74
(1 + 0.084 × 360
)
= FRF 9,830,264.11
.084 ENTER 74 × 360 ÷ 1+
10,000,000 ■ xy ÷
Key Point
40
Secondary market price = present value
(again!)
2 · The Money Market
Calculation
summary
For a discount instrument
Maturity proceeds = face value
Secondary market price =
face value
(1 + market yield ×
days left to maturity
year
)
Discount / true yield
In the USA and UK, a further complication arises in the way the interest rate
is quoted on discount instruments – as a “discount rate” instead of a yield. If
you invest 98.436 in a sterling time deposit or CD at 10 percent for 58 days,
you expect to receive the 98.436 back at the end of 58 days, together with
interest calculated as:
98.436 × 0.10 ×
58
= 1.564
365
In this case, the total proceeds at maturity – principal plus interest – are
98.436 + 1.564 = 100.00.
This means that you invested 98.436 to receive (98.436 + 1.564) = 100 at
the end of 58 days. If the same investment were made in a discount instrument, the face value of the instrument would be 100, and the amount of
discount would be 1.564. In this case, the discount rate is the amount of discount expressed as an annualized percentage of the face value, rather than as
a percentage of the original amount paid. The discount rate is therefore:
(1.564 ÷ 100) ×
365
= 9.84%
58
The discount rate is always less than the corresponding yield. If the discount
rate on an instrument is D, then the amount of discount is:
F × D × days
year
where F is the face value of the instrument.
The price P to be paid is the face value less the discount:
(
P = F × 1 – D × days
year
)
If we expressed the price in terms of the equivalent yield rather than the discount rate, we would still have the same formula as earlier:
P=
F
(1 + i × )
days
year
Combining these two relationships, we get:
41
Part 2 · Interest Rate Instruments
D=
i
1 + i × days
year
where i is the equivalent yield (often referred to as the “true yield”). This can
perhaps be understood intuitively, by considering that because the discount is
received at the beginning of the period whereas the equivalent yield is
received at the end, the discount rate should be the “present value of the
yield”. Reversing this relationship:
i=
D
1 – D × days
year
Instruments quoted on a discount rate in the USA and UK include domestic
currency treasury bills and trade bills, while a yield basis is used for loans,
deposits and certificates of deposit (CDs). USA CP is also quoted on a discount rate basis, while ECP and sterling CP are quoted on a yield basis. Note
however that while the sterling T-bills issued by the UK government are
quoted on a discount rate, the ECU T-bills it issues are quoted on a true
yield, as other international ECU instruments are.
Example 2.5
A USA treasury bill of $1 million is issued for 91 days at a discount rate of 6.5%.
What is the amount of the discount and the amount paid?
Amount of discount = $1 million × 0.065 ×
91
360
= $16,430.56
Price paid = face value – discount = $983,569.44
1,000,000 ENTER .065 × 91 × 360 ÷
1,000,000 ■ xy –
(Amount of discount)
(Amount paid)
Example 2.6
A UK treasury bill with remaining maturity of 70 days is quoted at a discount rate of
7.1%. What is the equivalent yield?
7.1%
1 – 0.071 ×
70
365
= 7.198%
Answer: 7.198%
.071 ENTER 70 × 365 ÷ 1 ■ xy –
7.1 ■ xy ÷
42
2 · The Money Market
Rate of true yield =
Discount rate =
Calculation
summary
discount rate
(1 – discount rate × )
days
year
rate of true yield
(1 + yield × )
days
year
Amount of discount = face value × discount rate × days
year
(
Amount paid = face value × 1 – discount rate × days
year
)
Instruments quoted on a discount rate
USA:
T-bills
BA
CP
UK:
Key Point
T-bills (£)
BA
Bond-equivalent yields
For trading purposes, a government treasury bond which has less than a
year left to maturity may be just as acceptable as a treasury bill with the
same maturity left. As the method used for quoting yields generally differs
between the two instruments, the rate quoted for treasury bills in the USA
is often converted to a “bond-equivalent yield” for comparison. This is
considered in Chapter 5.
CDS PAYING MORE THAN ONE COUPON
Most CDs are short-term instruments paying interest on maturity only.
Some CDs however are issued with a maturity of several years. In this case,
interest is paid periodically – generally every six months or every year. The
price for a CD paying more than one coupon will therefore depend on all
the intervening coupons before maturity, valued at the current yield.
Suppose that a CD has three more coupons yet to be paid, one of which
will be paid on maturity together with the face value F of the CD. The
amount of this last coupon will be:
43
Part 2 · Interest Rate Instruments
d
23
F × R × year
where: R = the coupon rate on the CD
d23 = the number of days between the second and third (last) coupon
year = the number of days in the conventional year.
The total amount paid on maturity will therefore be:
(
d
23
F × 1 + R × year
)
The value of this amount discounted to the date of the second coupon payment, at the current yield i, is:
(
d
23
F × 1 + R × year
)
(1 + i × )
d23
year
To this can be added the actual cashflow received on the same date – that is,
the second coupon, which is:
d
12
F × R × year
where d12 = the number of days between the first and second coupons.
The total of these two amounts is:
[
(1 + R × ) + R ×
F×
(1 + i × )
d23
year
d23
year
d12
year
]
Again, this amount can be discounted to the date of the first coupon payment
at the current yield i and added to the actual cashflow received then, to give:
F×
[
(1 + R × ) + R × + (R × )
(1 + i × ) (1 + i × ) (1 + i × )
d23
year
d23
year
d12
year
d12
year
d12
year
d01
year
]
where d01 = the number of days up to the first coupon since the previous
coupon was paid (or since issue if there has been no previous coupon)
Finally, this entire amount can be discounted to the purchase date, again
at the current yield of i, by dividing by:
(1 + i × )
dp1
year
where dp1 = the number of days between purchase and the first coupon date.
44
2 · The Money Market
The result will be the present value of all the cashflows, which should be
the price P to be paid. This can be written as:
P=
F
(1 + i × )(1 + i × )(1 + i × )
dp1
year
+
d12
year
F×R×
d23
year
d23
year
(1 + i × )(1 + i × )(1 + i × )
dp1
year
d12
year
d23
year
d
+
12
F × R × year
(1 + i × )(1 + i × )
dp1
year
d12
year
d
+
01
F × R × year
(1 + i × )
dp1
year
In general, for a CD with N coupon payments yet to be made:
P=F×
where: Ak
F
R
year
dk –1;k
dp1
[ (
[
1
R
N d
+
× ∑1 k–1;k
AN year
Ak
Calculation
summary
])]
=
(1 + i × )(1 + i × )(1 + i × )...(1 + i × )
=
=
=
=
=
face value of the CD
coupon rate of the CD
number of days in the conventional year
number of days between (k-1)th coupon and kth coupon
number of days between purchase and first coupon.
dp1
year
d12
year
d23
year
dk–1;k
year
Example 2.7
What is the amount paid for the following CD?
Face value:
Coupon:
Maturity date:
Settlement date:
Yield:
$1 million
8.0% semi-annual
13 September 1999
15 January 1998
7%
The last coupon date was 15 September 1997 (13 September was a Saturday).
Future coupons will be paid on 13 March 1998, 14 September 1998 (13 September
is a Sunday), 15 March 1999 (13 March is a Saturday) and 13 September 1999.
With the previous notation:
45
Part 2 · Interest Rate Instruments
d01 = 179, dp1 = 57, d12 = 185, d23 = 182, d34 = 182
Price =
+
+
+
$1 million × (1 + 0.08 × 182
360 )
57
1 + 0.07× 182
1 + 0.07 × 182
(1 + 0.07 × 360
)(1 + 0.07 × 185
360 )(
360 )(
360 )
$1 million × 0.08 × 182
360
57
1 + 0.07× 182
(1 + 0.07 × 360
)(1 + 0.07 × 185
360 )(
360 )
$1 million × 0.08 × 185
360
57
(1 + 0.07 × 360
)(1 + 0.07 × 185
360 )
$1 million × 0.08 × 179
360
57
(1 + 0.07 × 360
)
= $1,042,449.75
➞
TIME CALC
13.091999 DATE2 15.031999 DATE1 DAYS
360 ÷ .08 × 1 +
RCL DAYS 360 ÷ .07 × 1 + ÷
14.091998 DATE2 DAYS +/■ xy 360 ÷ .08 × +
RCL DAYS +/- 360 ÷ .07 × 1 + ÷
13.031998 DATE1 DAYS
■ xy 360 ÷ .08 × +
RCL DAYS 360 ÷ .07 × 1 + ÷
15.091997 DATE2 DAYS +/■ xy 360 ÷ .08 × +
15.011998 DATE2 DAYS +/■ xy 360 ÷ .07 × 1 + ÷
1,000,000 ×
➞
➞
➞
46
(d34)
(d23)
(d12)
(d01)
(dp1)
2 · The Money Market
EXERCISES
21. You invest in a 181-day sterling CD with a face value of £1,000,000 and a
coupon of 11%. What are the total maturity proceeds?
22. You buy the CD in the previous question 47 days after issue, for a yield of
10%. What amount do you pay for the CD?
You then sell the CD again after holding it for only 63 days (between purchase
and sale), at a yield to the new purchaser of 9.5%. What yield have you earned
on your whole investment on a simple basis? What is your effective yield?
23. At what different yield to the purchaser would you need to have sold in the
previous question, in order to achieve an overall yield on the investment to you
of 10% (on a simple basis)?
24. You place a deposit for 91 days at 11.5% on an ACT/360 basis. What would
the rate have been if it had been quoted on an ACT/365 basis? What is the
effective yield on an ACT/365 basis and on an ACT/360 basis?
25. You purchase some sterling Eurocommercial paper as follows:
Purchase value date:
Maturity value date:
Yield:
Amount:
2 July 1996
2 September 1996
8.2%
£2,000,000.00
What do you pay for the paper?
26. An investor seeks a yield of 9.5% on a sterling 1 million 60-day banker’s
acceptance. What is the discount rate and the amount of this discount?
27. If the discount rate were in fact 9.5%, what would the yield and the amount
paid for the banker’s acceptance be?
28. If the amount paid in the previous question is in fact £975,000.00, what is the
discount rate?
29. The rate quoted for a 91-day US treasury bill is 6.5%.
a. What is the amount paid for US$1,000,000.00 of this T-bill?
b. What is the equivalent true yield on a 365-day basis?
30. You buy a US treasury bill 176 days before it matures at a discount rate of 7%
and sell it again at a discount rate of 6.7% after holding it for 64 days. What
yield have you achieved on a 365-day year basis?
31. What would be the yield in the previous question if you sold it after only 4 days
at a discount rate of 7.5%?
47
Part 2 · Interest Rate Instruments
32. The market rate quoted for a 91-day T-bill is 5% in the USA, UK, Belgium and
France. Each T-bill has a face value of 1 million of the local currency. What is
the amount paid for the bill in each country?
33. Place the following instruments in descending order of yield, working from the
rates quoted:
1
30-day UK T-bill (£)
84%
30-day UK CP (£)
8 16%
30-day ECP (£)
1
88%
5
8 16%
1
84%
1
82%
5
88%
1
82%
30-day US T-bill
30-day interbank deposit (£)
30-day US CP
30-day US$ CD
30-day French T-bill
3
34. A US $1 million CD with semi-annual coupons of 7.5% per annum is issued on
26 March 1996 with a maturity of 5 years. You purchase the CD on 20 May
1999 at a yield of 8.0%. What is the amount paid?
48
■
■
■
“An important point is to
consider which comes first. Are
forward-forward rates (and
hence futures prices and FRA
rates) the mathematical result of
the yield curve? Or are the
market’s expectations of future
rates the starting point?”
50
3
Forward-Forwards
and Forward Rate
Agreements (FRAs)
Forward-forwards, FRAs and futures
Applications of FRAs
Exercises
51
Part 2 · Interest Rate Instruments
FORWARD-FORWARDS, FRAs AND FUTURES
Overview
Forward-forwards, forward rate agreements (FRAs) and futures are very similar and closely linked instruments, all relating to an interest rate applied to
some period which starts in the future. We shall first define them here and
then examine each more closely. Futures in particular will be considered in
the next chapter.
Terminology
A forward-forward is a cash borrowing or deposit which starts on one forward date and ends on another forward date. The term, amount and
interest rate are all fixed in advance. Someone who expects to borrow or
deposit cash in the future can use this to remove any uncertainty relating
to what interest rates will be when the time arrives.
An FRA is an off-balance sheet instrument which can achieve the same economic effect as a forward-forward. Someone who expects to borrow cash
in the future can buy an FRA to fix in advance the interest rate on the borrowing. When the time to borrow arrives, he borrows the cash in the usual
way. Under the FRA, which remains quite separate, he receives or pays the
difference between the cash borrowing rate and the FRA rate, so that he
achieves the same net effect as with a forward-forward borrowing.
A futures contract is similar to an FRA – an off-balance sheet contract for
the difference between the cash interest rate and the agreed futures rate.
Futures are however traded only on an exchange, and differ from FRAs
in a variety of technical ways.
Pricing a forward-forward
Suppose that the 3-month sterling interest rate is 13.0 percent and the
6-month rate is 13.1 percent. If I borrow £100 for 6 months and simultaneously deposit it for 3 months, I have created a net borrowing which begins in
3 months and ends in 6 months. The position over the first 3 months is a net
zero one. If I undertake these two transactions at the same time, I have created a forward-forward borrowing – that is, a borrowing which starts on one
forward date and ends on another.
Example 3.1
If I deposit £1 for 91 days at 13%, then at the end of the 91 days, I receive:
£1 + 0.13 × 91 = £1.03241
365
52
3 · Forward-Forwards and Forward Rate Agreements (FRAs)
If I borrow £1 for 183 days at 13.1%, then at the end of the 183 days, I must repay:
£1 + 0.131 × 183 = £1.06568
365
My cashflows are: an inflow of £1.03241 after 91 days and an outflow of £1.06568
after 183 days. What is the cost of this forward-forward borrowing? The calculation
is similar to working out a yield earlier in the book:
cost =
outflow at the end
year
1.06568
365
– 1) ×
=
– 1) ×
( cash
cash inflow at the start
days ( 1.03241
92
= 12.79%
.131 ENTER 183 × 365 ÷ 1 +
.13 ENTER 91 × 365 ÷ 1 +
÷
1–
365 × 92 ÷
(value after 183 days)
(value after 91 days)
(forward-forward interest rate)
In general:
dL
year
year
Forward-forward rate =
–1 ×
dS
dL – dS
1 + iS × year
[
where: iL
iS
dL
dS
year
=
=
=
=
=
(
(
1 + iL ×
)
)
](
Calculation
summary
)
interest rate for longer period
interest rate for shorter period
number of days in longer period
number of days in shorter period
number of days in conventional year
Note that this construction of a theoretical forward-forward rate only applies
for periods up to one year. A money market deposit for longer than one year
typically pays interim interest after one year (or each six months). This extra
cashflow must be taken into account in the forward-forward structure. This
is explained in Chapter 6.
Forward rate agreements (FRAs)
An FRA is an off-balance sheet agreement to make a settlement in the future
with the same economic effect as a forward-forward. It is an agreement to
pay or receive, on an agreed future date, the difference between an agreed
interest rate and the interest rate actually prevailing on that future date, calculated on an agreed notional principal amount. It is settled against the
actual interest rate prevailing at the beginning of the period to which it
relates, rather than paid as a gross amount.
53
Part 2 · Interest Rate Instruments
Example 3.2
A borrower intends to borrow cash at LIBOR from 91 days forward to 183 days
forward, and he fixes the cost with an FRA. His costs will be as follows:
Receive LIBOR
under FRA
Pay LIBOR
to cash lender
Borrower
Pay fixed FRA rate
under FRA
His flows will therefore be: – LIBOR
+ LIBOR
– FRA rate
net cost: – FRA rate
If the cash is actually borrowed at a different rate – say LIBOR + –41 % – then the net
cost will be (FRA rate + –41 %), but the all-in cost is still fixed.
Pricing
In calculating a theoretical FRA price, we can apply exactly the same ideas as
in the forward-forward calculation above. As we are not actually borrowing
cash with the FRA however, we might calculate using middle rates for both
the 6-month and the 3-month period – rather than separate bid and offered
rates. Conventionally, however, FRAs are always settled against LIBOR
rather than LIMEAN. As a calculation using middle rates produces a rate
which is comparable to LIMEAN, we would therefore need to add the difference between LIMEAN and LIBOR – generally around œ_q¥ percent – to this
theoretical “middle price” forward-forward. An alternative approach is to
base the initial theoretical price calculation on LIBOR, rather than LIMEAN,
for both periods. The result is different, but generally only very slightly.
Quotation
Having established a theoretical FRA price, a dealer would then build a
spread round this price.
In Example 3.1, the theoretical FRA rate could be calculated as: 12.785%
+ 0.0625% = 12.85%. Putting a spread of, say, six basis points around this
would give a price of 12.82% / 12.8%. A customer wishing to hedge a future
borrowing (“buying” the FRA) would therefore deal at 12.88 percent. A customer wishing to hedge a future deposit (“selling” the FRA) would deal at
12.82 percent.
An FRA is referred to by the beginning and end dates of the period covered.
Thus a “5 v 8” FRA is one to cover a 3-month period, beginning in 5 months
and ending in 8 months. Our example above would be a “3 v 6” FRA.
54
3 · Forward-Forwards and Forward Rate Agreements (FRAs)
Settlement
Suppose that the actual 3-month LIBOR, in 3 months’ time, is 11.5 percent.
Settlement then takes place between these two rates. On a principal of £100,
the effective interest settlement in our example would be:
£100 × (0.1288 – 0.1150) × 92 = £0.3478
365
As the settlement rate of 11.50 percent is lower than the agreed FRA rate,
this amount is due from the FRA buyer to the other party. Conventionally
however, this settlement takes place at the beginning of the 3-month borrowing period. It is therefore discounted to a present value at the current
3-month rate to calculate the actual settlement amount paid:
£100 × (0.1285 – 0.1150) ×
1 + 0.1150 ×
92
365
92
365
= £0.3307
In general:
The FRA settlement amount = principal ×
days
(f – L) × year
(
days
1 + L × year
Calculation
summary
)
where: f
L
= FRA rate
= interest rate (LIBOR) prevailing at the beginning of
the period to which the FRA relates
days = number of days in the FRA period
year = number of days in the conventional year.
If the period of the FRA is longer than one year, the corresponding LIBOR
rate used for settlement relates to a period where interest is conventionally
paid at the end of each year as well as at maturity. A 6 v 24 FRA, for example, covers a period from 6 months to 24 months and will be settled against
an 18-month LIBOR rate at the beginning of the FRA period.
An 18-month deposit would, however, typically pay interest at the end of
one year and after 18 months. The agreed FRA rate and the settlement
LIBOR would therefore be based on this. As FRA settlements are paid at the
beginning of the period on a discounted basis, each of these payments therefore needs to be discounted separately. Strictly, the net settlement payment
calculated for the end of 18 months should be discounted at an appropriate
compounded 18-month rate and the net settlement amount calculated for the
end of the first year should be discounted at 1-year LIBOR. In practice, the
FRA settlement LIBOR is generally used for both. In this case, the final discounted settlement amount would be:
55
Part 2 · Interest Rate Instruments
Calculation
summary
d
principal ×
1
(f – L) × year
+
(f – L) ×
d2
year
(1 + L × ) (1 + L × ) × (1 + L × )
d1
year
d1
year
d2
year
where: d1 = number of days in the first year of the FRA period
d2 = number of days from d1 until the end of the FRA period.
This same principle can be applied to the settlement of FRAs covering any period.
The short-term yield curve
A “yield curve” shows how interest rates vary with term to maturity. For
example, a Reuters screen might show the following rates:
1 month
2 months
3 months
6 months
12 months
2 years
9.5%
9.7%
10.0%
10.0%
10.2%
10.5%
In a free market, these rates show where the market on average believes rates
“should” be, as supply and demand would otherwise tend to move them up
or down. Clearly the rates at some maturity level or levels are influenced by
central bank policy. If the market believes that the central bank is about to
change official 3-month rates, for example, this expectation will already have
been factored into the market 3-month rate.
If the 3-month maturity is indeed the rate manipulated by the central bank
for this particular currency, a more logical curve to look at might be one that
shows what the market expects 3-month rates to be at certain times in the
future. For example, what is the 3-month rate now, what will it be after
1 month, after 2 months, after 3 months, etc? Given enough such rates, it is
possible to work “backwards” to construct the yield curve shown above.
Suppose, for example, that the 3-month rate now is 10.0 percent and the
market expects that there will be a 0.25 percent cut in rates during the next
3 months – so that at the end of 3 months, the 3-month rate will be
9.75 percent. Given these data, what should the 6-month rate be now?
The answer must be the rate achieved by taking the 3-month rate now,
compounded with the expected 3-month rate in 3 months’ time; otherwise
there would be an expected profit in going long for 3 months and short for
6 months or vice versa, and the market would tend to move the rates. In this
way, the 6-month rate now can be calculated as:
91 × 1 + 0.0975 × 92 – 1 × 360 = 10.00%
) (
[(1 + 0.10 × 360
] 183
360 )
This rate is in fact the 6-month rate shown above. If we now work in the
other direction, we would find that the forward-forward rate from 3 months
to 6 months (“3 v 6”) would be 9.75 percent as expected:
56
3 · Forward-Forwards and Forward Rate Agreements (FRAs)
[
]
(1 + 0.10 × ) – 1
(1 + 0.10 × )
183
360
91
360
× 360 = 9.75%
92
This shows that a “flat” short-term yield curve – in our example, the 3month and 6-month rates are the same at 10.0 percent – does not imply that
the market expects interest rates to remain stable. Rather, it expects them
to fall.
An important point here is to consider the question of which comes first.
Are forward-forward rates (and hence futures prices and FRA rates) the
mathematical result of the yield curve? Or are the market’s expectations of
future rates (i.e. forward-forwards, futures and FRAs) the starting point, and
from these it is possible to create the yield curve? The question is a circular
one to some extent, but market traders increasingly look at constructing a
yield curve from expected future rates for various periods and maturities.
Constructing a strip
In the previous section, when we compounded the 3-month rate now with
the expected 3-month rate in 3 months’ time, we were effectively creating a
“strip” – that is, a series of consecutive legs which, compounded together,
build up to a longer overall period.
Example 3.3
Suppose that it is now January and we have the following rates available. At what
cost can we construct a fixed-rate borrowing for 9 months? All rates are ACT/360.
3-month LIBOR:
3 v 6 FRA:
6 v 9 FRA:
8.5% (92 days)
8.6% (91 days)
8.7% (91 days)
We construct the strip as follows:
•
•
•
•
•
borrow cash now for 3 months;
buy a 3 v 6 FRA now based on the total repayment amount in
April (principal plus interest);
refinance this total amount in April at the 3-month LIBOR in April;
buy a 6 v 9 FRA now based on the total repayment amount in
July (principal plus interest calculated at the 3 v 6 FRA rate now);
refinance this amount in July at the 3-month LIBOR in July.
Suppose that in April when the first FRA settles, 3-month LIBOR is 9.0% and that
in July when the second FRA settles, 3-month LIBOR is 9.5%. Although market
practice is for the FRA settlements to be made at the beginning of the relevant
period discounted at LIBOR, the economic effect is the same as if the settlement
were at the end of the period but not discounted – assuming that the discounted
settlement amount could simply be invested or borrowed at LIBOR for the period.
For clarity, we will therefore assume that the FRA settlements are at the ends of the
periods and not discounted.
57
Part 2 · Interest Rate Instruments
This gives us the following cashflows based on a borrowing of 1:
January: + 1
92
(repayment)
(
360)
92
(refinancing)
+ (1 + 0.085 × 360)
92
91
(repayment)
July:
– (1 + 0.085 × 360) × (1 + 0.09 × 360)
92
91
(FRA settlement)
+ (1 + 0.085 × 360) × (0.09 – 0.086) × 360
92
91
(refinancing)
+ (1 + 0.085 × 360) × (1 + 0.086 × 360)
92
91
91
(repayment)
October: – (1 + 0.085 × 360) × (1 + 0.086 × 360) × (1 + 0.095 × 360)
92
91
91
+ (1 + 0.085 × 360) × (1 + 0.086 × 360) × (0.095 – 0.087) × 360 (FRA settlement)
April:
– 1 + 0.085 ×
Most of these flows offset each other, leaving the following net flows:
January: + 1
(
October: – 1 + 0.085 ×
91
91
) × (1 + 0.086 × 360
) × (1 + 0.087 × 360
) = –1.066891
92
360
The cost of funding for 9 months thus depends only on the original cash interest rate
for 3 months and the FRA rates, compounded together. The cost per annum is:
(1.066891 – 1) ×
360
= 8.79%
274
In general:
Calculation
summary
The interest rate for a longer period up to one year =
d
d
d
year
1 + i1 × 1 × 1 + i2 × 2 × 1 + i3 × 3 × .... – 1 ×
year
year
year
total days
[(
) (
) (
)
]
where: i1, i2, i3, ... are the cash interest rate and forward-forward rates for a
series of consecutive periods lasting d1, d2, d3, ... days.
APPLICATIONS OF FRAs
As with any instrument, FRAs may be used for hedging, speculating or arbitrage, depending on whether they are taken to offset an existing underlying
position or taken as new positions themselves.
Hedging
Example 3.4
A company has a 5-year borrowing with 3-monthly rollovers – that is, every three
months, the interest rate is refixed at the prevailing 3-month LIBOR. The company
expects interest rates to rise before the next rollover date. It therefore buys an FRA to
58
3 · Forward-Forwards and Forward Rate Agreements (FRAs)
start on the next rollover date and finish 3 months later. If the next rollover date is 2
months away, this would be a “2 v 5” FRA. If the company is correct and interest
rates do rise, the next rollover will cost more, but the company will make a profit on
the FRA settlement to offset this. If rates fall however, the next rollover will be
cheaper but the company will make an offsetting loss on the FRA settlement. The
FRA settlement profit or loss will of course depend on how the 3-month rate stands
after two months compared with the FRA rate now, not compared with the cash rate
now. Either way, the net effect will be that the company’s borrowing cost will be
locked in at the FRA rate (plus the normal margin which it pays on its credit facility):
Company pays
Company pays
Company receives
Net cost
LIBOR + margin
FRA rate
LIBOR
FRA rate + margin
to lending bank
to FRA counterparty
from FRA counterparty
The FRA payments are in practice netted and also settled at the beginning of the
borrowing period after discounting. The economic effect is still as shown.
Example 3.5
A company expects to make a 6-month deposit in two weeks’ time and fears that
interest rates may fall. The company therefore sells a 2-week v 6 –12 -month FRA.
Exactly as above, but in reverse, the company will thereby lock in the deposit rate.
Although the company may expect to receive LIBID on its actual deposit, the FRA
will always be settled against LIBOR:
Company receives
Company receives
Company pays
Net return
LIBID
from deposit
FRA rate
from FRA counterparty
LIBOR
to FRA counterparty
FRA rate – (LIBOR – LIBID)
As the FRA rate is theoretically calculated to be comparable to LIBOR, it is reasonable to expect the net return to be correspondingly lower than the FRA rate by the
(LIBID – LIBOR) spread.
Speculation
The most basic trading strategy is to use an FRA to speculate on whether the
cash interest rate when the FRA period begins is higher or lower than the
FRA rate. If the trader expects interest rates to rise, he buys an FRA; if he
expects rates to fall, he sells an FRA.
Example 3.6
A bank with no position expects interest rates to rise. The bank therefore buys an FRA.
If rates rise above the FRA rate it will make a profit; otherwise it will make a loss.
Arbitrage
Arbitrage between FRAs and futures is considered later.
59
Part 2 · Interest Rate Instruments
EXERCISES
35. Current market rates are as follows for SEK:
3 months (91 days)
6 months (182 days)
9 months (273 days)
9.87 / 10.00%
10.12 / 10.25%
10.00 / 10.12%
What is the theoretical FRA 3 v 9 for SEK now?
36. You borrow DEM 5 million at 7.00% for 6 months (183 days) and deposit DEM
5 million for 3 months (91 days) at 6.75%. You wish to hedge the mismatched
position, based on the following FRA prices quoted to you:
3 v 6: 7.10% / 7.15%
6 v 9: 7.20% / 7.25%
a. Do you buy or sell the FRA?
b. At what price?
c. For a complete hedge, what amount do you deal?
When it comes to fixing the FRA, the 3-month rate is 6.85% / 6.90%:
d. What is the settlement amount? Who pays whom?
e. What is the overall profit or loss of the book at the end of six months, assuming that your borrowings are always at LIBOR and your deposits at LIBID?
60
■
■
■
“In general, a futures contract
in any market is a contract in
which the commodity being
bought and sold is considered
as being delivered (even though
this may not physically occur)
at some future date rather
than immediately.”
62
4
Interest Rate Futures
Overview
Exchange structure and margins
Futures compared with FRAs
Pricing and hedging FRAs with futures
Trading with interest rate futures
Exercises
63
Part 2 · Interest Rate Instruments
OVERVIEW
In general, a futures contract in any market is a contract in which the commodity being bought and sold is considered as being delivered (even though
this may not physically occur) at some future date rather than immediately –
hence the name. The significant differences between a “futures contract” and
a “forward” arise in two ways. First, a futures contract is traded on a particular exchange (although two or more exchanges might trade identically
specified contracts). A forward however, which is also a deal for delivery on
a future date, is dealt “over the counter” (OTC) – a deal made between any
two parties, not on an exchange. Second, futures contracts are generally standardized, while forwards are not. The specifications of each futures contract
are laid down precisely by the relevant exchange and vary from commodity
to commodity and from exchange to exchange. Some contracts, for example,
specifically do not allow for the commodity to be delivered; although their
prices are calculated as if future delivery takes place, the contracts must be
reversed before the notional delivery date, thereby capturing a profit or a
loss. Interest rate futures, for example, cannot be delivered, whereas most
bond futures can.
The theory underlying the pricing of a futures contract depends on the
underlying “commodity” on which the contract is based. For a futures contract based on 3-month interest rates, for example, the pricing is based on
forward-forward pricing theory, explained earlier. Similarly, currency futures
pricing theory is the same as currency forward outright pricing theory and
bond futures pricing theory is based on bond pricing.
The principle – and the different characteristics of interest rate and currency futures – are most easily understood by examples.
Example 4.1
A 3-month EuroDEM interest rate futures contract traded on LIFFE:
Exchange LlFFE (London International Financial Futures and Options Exchange),
where a variety of futures and options contracts on interest rates, bonds, equities
and commodities is traded.
Commodity The basis of the contract is a deposit of DEM 1 million (EuroDEM)
lasting for 90 days based on an ACT/360 year.
Delivery It is not permitted for this contract to be delivered; if a trader buys such a
contract, he cannot insist that, on the future delivery date, his counterparty makes
arrangements for him to have a deposit for 90 days from then onwards at the interest rate agreed. Rather, the trader must reverse his futures contract before
delivery, thereby taking a profit or loss.
Delivery date The contract must be based on a notional delivery date. In this
case, the delivery date must be the first business day before the third Wednesday
of the delivery month (March, June, September, December and the next two
months following dealing).
64
4 · Interest Rate Futures
Trading It is possible to trade the contract until 11:00 am on the last business day
before the delivery day. Trading hours are from 07:30 to 16:10 each business day
in London for “open outcry” (physical trading, face to face on the exchange), and
from 16:25 to 17:59 for “APT” (automated pit trading – computerized trading outside the exchange).
Price The price is determined by the free market and is quoted as an index rather
than an interest rate. The index is expressed as 100 minus the implied interest rate.
Thus a price of 93.52 implies an interest rate of 6.48% (100 – 93.52 = 6.48).
Price movement Prices are quoted to two decimal places and can move by as
little as 0.01. This minimum movement is called a “tick” and is equivalent to a profit
or loss of DEM 25. This is calculated as:
Amount of contract × price movement ×
days
year
= DEM 1 million × 0.01% × 90 = DEM 25
360
Settlement price At the close of trading, LIFFE declares an Exchange Delivery
Settlement Price (EDSP) which is the closing price at which any contracts still outstanding will be automatically reversed. The EDSP is 100 minus the British
Bankers’ Association 3-month LIBOR.
Example 4.2
Yen/dollar futures contract traded on the IMM:
Exchange IMM (International Monetary Market; a division of CME, Chicago
Mercantile Exchange, where futures and options on currencies, interest rates equities and commodities are traded).
Commodity The basis of the contract is JPY 12.5 million.
Delivery It is possible for the JPY 12.5 million to be delivered, if the contract is not
reversed before maturity, against an equivalent value in USD.
Delivery date The third Wednesday in January, March, April, June, July, September,
October and December, as well as the month in which the current spot date falls.
Trading It is possible to trade the contract until 09:16 two business days before
the delivery date. Trading hours are from 07:20 to 14:00 each business day in
Chicago for open outcry, and from 14:30 to 07:05 Monday to Thursday, 17:30 to
07:05 Sundays on GLOBEX (computerized trading outside the exchange – only the
next four March / June / September / December months traded on GLOBEX).
Price The price is expressed as the dollar value of JPY 1.
Price movement Prices are quoted to six decimal places, with a minimum movement (one tick) of $0.000001. A one tick movement is equivalent to a profit or loss
of USD 12.50.
Settlement price At the close of trading, the EDSP is the closing spot JPY/USD
rate as determined by the IMM.
The typical contract specification for short-term interest rate futures is for a
“3-month” interest rate, although, for example, 1-month contracts also exist
65
Part 2 · Interest Rate Instruments
in some currencies on some exchanges. The precise specification can vary
from exchange to exchange but is in practice for one-quarter of a year. Thus
the sterling 3-month interest rate futures contract traded on LIFFE, for example, technically calculates 91q-® days’ settlement.
Suppose, for example, that the sterling futures price moves from 92.40 to
92.90 (an implied interest rate change of 0.5 percent). The settlement amount
would be:
Contract amount × 0.0050 × ®-q
As sterling interest rates are conventionally calculated on an ACT/365 basis,
this is equivalent to:
Contract amount × 0.0050 ×
Calculation
summary
91®-q
365
Short-term interest rate futures:
Price = 100 – (implied forward-forward interest rate × 100)
Profit / loss on long position in a 3-month contract =
notional contract size ×
(sale price – purchase price) 1
×
100
4
EXCHANGE STRUCTURE AND MARGINS
Market participants
The users of an exchange are its members and their customers. An exchange
also has “locals” – private traders dealing for their own account only.
Dealing
There are two methods of dealing. The first, traditional, method is “open
outcry”, whereby the buyer and seller deal face to face in public in the
exchange’s “trading pit”. This should ensure that a customer’s order will
always be transacted at the best possible rate. The second is screen-trading,
designed to simulate the transparency of open outcry. In some cases (such as
LIFFE’s “automated pit trading”), this is used for trading outside normal
business hours. Some exchanges however use only screen-based trading.
Clearing
The futures exchange is responsible for administering the market, but all
transactions are cleared through a clearing house, which is usually separate.
On LIFFE, for example, this function is performed by the London Clearing
House (LCH). Following confirmation of a transaction, the clearing house
substitutes itself as a counterparty to each user and becomes the seller to
every buyer and the buyer to every seller.
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4 · Interest Rate Futures
Margin requirements
In order to protect the clearing house, clearing members are required to place collateral with it for each deal transacted. This collateral is called “initial margin”.
Members are then debited or credited each day with “variation margin”
which reflects the day’s loss or profit on contracts held. Customers, in turn,
are required to pay initial margin and variation margin to the member
through whom they have dealt. The initial margin is intended to protect the
clearing house for the short period until a position can be revalued and variation margin called for if necessary. As variation margin is paid each day,
the initial margin is relatively small in relation to the potential price movements over a longer period.
The calculation of variation margin is equivalent to “marking to market”
– that is, revaluing a futures contract each day at the current price. The variation margin required is the tick value multiplied by the number of ticks price
movement. For example, if the tick value is DEM 25 on each contract, and
the price moves from 94.73 to 94.21 (a fall of 52 ticks), the loss on a long
futures contract is DEM (25 × 52) = DEM 1,300. Depending on the size of
initial margin already placed with the exchange, and the exchange’s current
rules, a variation margin may not be called for below a certain level.
Delivery
A futures position can be closed out by means of an exactly offsetting transaction. Depending on the specification of the particular futures contract,
contracts which are not settled before maturity are required to be either
“cash settled” – that is, reversed at maturity and the price difference paid –
or (if delivery is permitted) delivered. The mechanics of the delivery process
differ for each type of contract.
Limit up / down
Some markets impose limits on trading movements in an attempt to prevent
wild price fluctuations and hence limit risk to some extent. For example,
when the IMM opens in the morning, it is not possible for the opening price
in the yen/dollar futures contract to differ from the previous day’s closing
price by more than 200 ticks.
FUTURES COMPARED WITH FRAs
An FRA is an OTC equivalent to an interest rate futures contract. Exactly the
same forward-forward pricing mechanism is therefore used to calculate a
futures price – although the futures price is then expressed as an index (100 –
rate). In practice, an FRA trader will often take his price from the futures
market (which may not be precisely in line with the theoretical calculations),
67
Part 2 · Interest Rate Instruments
rather than directly from the forward-forward calculation. This is because
the FRA trader would use the futures market rather than a forward-forward
to hedge his FRA book – because of both the balance sheet implications and
the transaction costs. In practice therefore, the FRA rate for a period coinciding with a futures contract would be (100 – futures price).
An important practical difference between FRAs and futures is in the settlement mechanics. An FRA settlement is paid at the beginning of the
notional borrowing period, and is discounted. The futures “settlement” – the
profit or loss on the contract – is also all settled by the same date, via the
margin payments made during the period from transaction until the futures
delivery date. However, in most futures markets, this settlement is not discounted. A 90-day FRA is not therefore exactly matched by an offsetting
futures contract even if the amounts and dates are the same.
It should also be noted that FRAs and futures are “in opposite directions.”
A buyer of an FRA will profit if interest rates rise. A buyer of a futures contract will profit if interest rates fall. If a trader sells an FRA to a counterparty,
he must therefore also sell a futures contract to cover his position.
OTC vs. exchange-traded
It is worthwhile summarizing the differences between OTC contracts such as
an FRA, and futures contracts.
Key Point
Amount The amount of a futures contract is standardized. The amount
of an OTC deal is entirely flexible.
Delivery date The delivery date of a futures contract is standardized. The
delivery date of an OTC deal is entirely flexible.
Margin Dealing in futures requires the payment of collateral (called
“initial margin”) as security. In addition, “variation margin” is paid
or received each day to reflect the day’s loss or profit on futures contracts held. When trading OTC, professional traders usually deal on
the basis of credit lines, with no security required.
Settlement Settlement on an instrument such as an FRA is discounted to
a present value. Settlement on a futures contract, because it is paid
through variation margin, is not discounted.
Credit risk The margin system ensures that the exchange clearing house
is generally fully protected against the risk of default. As the
counterparty to each futures contract is the clearing house, there is
therefore usually virtually no credit risk in dealing futures. OTC
counterparties are generally not of the same creditworthiness.
Delivery Some futures contracts are not deliverable and must be cash settled.
It is usually possible to arrange an OTC deal to include delivery.
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4 · Interest Rate Futures
Liquidity and spread Standardization and transparency generally ensure a
liquid market in futures contracts, together with narrower spreads
between bid and offer than in OTC deals. For delivery dates far in the
future on the other hand, there may be insufficient liquidity in the
futures market, where an OTC price may be available.
Underlying commodity Futures contracts are not available in all underlying
commodities. For example, there is no ringgit/peseta futures contract
but a ringgit/peseta forward is easily available.
PRICING AND HEDGING FRAs WITH FUTURES
In Chapter 3 on forward-forwards and FRAs, we calculated FRA rates from
cash market interest rates – for example, a 3 v 6 FRA from a 3-month interest rate and a 6-month interest rate. In practice, however, a trader may well
generate an FRA price from futures prices and also hedge the resulting position by buying or selling futures.
Example 4.3
Suppose we have the following prices on 17 March for DEM and wish to sell a 3 v
6 FRA for DEM 10 million. How should the FRA be priced (ignoring any buy / sell
spread) and hedged, based on these prices?
June futures price (delivery 18 June):
Sept futures price (delivery 17 Sept):
Dec futures price (delivery 17 Dec):
91.75 (implied interest rate: 8.25%)
91.50 (implied interest rate: 8.50%)
91.25 (implied interest rate: 8.75%)
The FRA will be for the period 19 June to 19 September (92 days) and will settle
against LIBOR fixed on 17 June. The June futures contract EDSP will also be
LIBOR on 17 June. The FRA rate should therefore be the implied June futures rate
of 8.25%.
The settlement amount for the FRA will be:
DEM 10 million × (0.0825 – LIBOR) ×
1 + LIBOR ×
92
360
92
360
The profit or loss on the futures contract (which is not discounted) is:
number of contracts × DEM 1 million × (0.0825 – LIBOR) ×
90
360
In order for these to be equal, we need:
number of contracts = 10 ×
92
90
(1 + LIBOR × )
92
360
We do not know what LIBOR will be. Taking 8.25% as our best guess however,
we have:
69
Part 2 · Interest Rate Instruments
number of contracts = 10 ×
92
90
(1 + 0.0825 × )
92
360
= 10.01
As futures contracts can only be traded in whole numbers, we hedge by selling 10
futures contracts.
In Chapter 3, we considered a strip of FRAs to create a rate for a longer
period. The same theory applies just as well here.
Example 4.4
With the same prices as in Example 4.3, we wish to sell a 3 v 9 FRA and a 6 v 12
FRA. How should these be priced and hedged?
A 3 v 6 FRA can be priced at 8.25% and hedged exactly as in Example 4.3. A 6 v 9
FRA (91 days from 19 September to 19 December) can similarly be priced at the
implied September futures rate of 8.50% and hedged by selling 10 September
futures (although there is a slight discrepancy in the dates as the futures contract
delivery is 17 September). The 3 v 9 FRA should be equivalent to a strip combining
the 3 v 6 FRA and 6 v 9 FRA (because, if not, there would be an arbitrage opportunity). This gives the 3 v 9 FRA rate as:
[(
1 + 0.0825 ×
) (
) ]
92
91
360
× 1 + 0.085 ×
–1 ×
= 8.463%
360
360
183
The hedge required is the combination of the hedges for each leg: sell 10 June
futures and 10 September futures.
In the same way, we can build up the 6 v 12 FRA from a strip of the 6 v 9 FRA and
9 v 12 FRA (90 days, from 19 December to 19 March), and hedge it by selling
10 September futures and 10 December futures.
[(
1 + 0.085 ×
) (
) ]
91
90
360
× 1 + 0.875 ×
–1 ×
= 8.718%
360
360
181
In Example 4.4, when we reach 17 June, we need to close out the June and
September futures hedges against the 3 v 9 FRA. The June contract will be
closed at the current 3-month LIBOR and the September contract at the current futures price which will approximate the current 3 v 6 FRA; combined
in a strip, these two rates approximate to the current 6-month LIBOR
against which the 3 v 9 FRA will settle at the same time. The hedge therefore
works. The result of the hedge is not perfect however, for various reasons:
• In creating a strip of FRAs, we compounded, by increasing the notional
•
•
•
70
amount for each leg to match the previous leg’s maturing amount. With
futures, we cannot do this – futures contracts are for standardized
notional amounts only.
Similarly, the futures profit / loss is based on a 90-day period rather than
91 or 92 days etc. as the FRA period.
FRA settlements are discounted but futures settlements are not.
The futures price when the September contract is closed out in June may
not exactly match the theoretical forward-forward rate at that time.
4 · Interest Rate Futures
• Even if the September futures price does exactly match the theoretical forward-forward rate, there is in fact a slight discrepancy in dates. On
17 June, the 3 v 6 FRA period is 19 September to 19 December (LIBOR is
therefore fixed on 17 September) but the September futures delivery is
17 September (EDSP is therefore fixed on 16 September).
The result of these effects is considered later, in Example 4.9.
Pricing FRAs from futures in this way is not as theoretically straightforward
as pricing FRAs from the cash market because in practice, the FRA period is
unlikely to coincide exactly with a futures date. If we only have 3-month
futures prices available, we only know what the market expects 3-month interest rates to be at certain times in the future. We do not know what 3-month
rates are expected to be at any other time, or, for example, what 4-month or
5-month rates are expected to be at any time. We therefore need to interpolate
between the prices we do have, to build up the rates we need.
Example 4.5
With the same prices as in Example 4.3, we wish to sell a 3 v 8 FRA (153 days from
19 June to 19 November) and a 6 v 11 FRA (153 days, from 19 September to
19 February). How do we price and hedge these?
For the 3 v 8 FRA, we are effectively asking what the market expects the 5-month
rate to be in 3 months’ time. The information available is what the market expects
the 3-month rate to be in 3 months’ time (8.25%, the 3 v 6 rate) and what it
expects the 6-month rate to be at the same time (8.463%, the 3 v 9 rate from
Example 4.4). An approach is therefore to interpolate, to give the 3 v 8 FRA as:
3 v 6 + (3 v 9 – 3 v 6) ×
(days in 3 v 8 – days in 3 v 6)
(days in 3 v 9 – days in 3 v 6)
= 8.25% + (8.463% – 8.25%) ×
153 – 92
= 8.393%
183 – 92
The hedge can similarly be considered as the sale of the following futures contracts:
10 June + (10 June + 10 September – 10 June) ×
153 – 92
183 – 92
= 10 June + 6.7 September
We therefore sell 10 June futures and 7 September futures.
In the same way, we can interpolate between the 6 v 9 rate and the 6 v 12 rate for
the 6 v 11 rate:
6 v 9 + (6 v 12 – 6 v 9) ×
(days in 6 v 11 – days in 6 v 9)
(days in 6 v 12 – days in 6 v 9)
= 8.50% + (8.718% – 8.50%) ×
153 – 91
= 8.650%
181 – 91
This is hedged by selling 10 September futures and 7 December futures.
So far, we have considered FRAs where the start of the FRA period coincides
with a futures contract. In practice, we need to be able to price an FRA
which starts between two futures dates. Again, interpolation is necessary.
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Part 2 · Interest Rate Instruments
Example 4.6
With the same prices as before, we wish to sell and hedge a 5 v 10 FRA.
From the previous example, we have the following prices:
3 v 8 FRA (153 days from 19 June to 19 November): 8.393%, hedged by selling
10 June futures and 7 September futures
6 v 11 FRA (153 days from 19 September to 19 February): 8.650%, hedged by selling 10 September futures and 7 December futures
We are now asking what the market expects the 5-month rate to be in 5 months’
time. The information available is what the market expects this rate to be in 3
months’ time and in 6 months’ time. An approach is therefore to interpolate again,
to give the 5 v 10 FRA as:
3 v 8 + (6 v 11 – 3 v 8) ×
(days to fixing 5 v 10 – days to fixing 3 v 8)
(days to fixing 6 v 11 – days to fixing 3 v 8)
= 8.393% + (8.650% – 8.393%) ×
153 – 92
= 8.563%
184 – 92
The hedge for this would follow the same approach, as a sale of the following
futures contracts:
(10 June + 6.7 Sept) + (10 Sept + 6.7 Dec – 10 June – 6.7 Sept) ×
153 – 92
184 – 92
= 3.4 June + 8.9 September + 4.4 December
We would really like to sell 16.7 contracts. As before, we need to approximate by
selling 17 contracts. We could therefore for example sell 3 June futures, 10
September futures and 4 December futures. (The extra September contract is an
approximation for 0.4 June and 0.4 December.)
In these examples we have built up a 5 v 10 FRA by interpolating in two stages:
(i) interpolate between known rates for different standard forward periods
but starting from the same time:
3 v 8 from 3 v 6 and 3 v 9
6 v 11 from 6 v 9 and 6 v 12
(ii) interpolate between rates for the same non-standard period but starting
from different times:
5 v 10 from 3 v 8 and 6 v 11
An alternative would be to approach these operations in reverse:
(i) interpolate between known rates for the same standard forward periods
but starting from different times:
5 v 8 from 3 v 6 and 6 v 9
5 v 11 from 3 v 9 and 6 v 12
(ii) interpolate between rates for different standard periods but starting from
the same non-standard time:
5 v 10 from 5 v 8 and 5 v 11
72
4 · Interest Rate Futures
The result of this approach would be slightly different but generally not significantly. Neither approach is perfect. However the 5 v 10 rate is calculated,
it is an estimate for a particular forward period, from a particular time, neither of which can actually be known from the current futures prices.
Hedging the basis risk
In Example 4.6, the hedge put in place in March for selling the 5 v 10 FRA
was to sell 3 June futures, 10 September futures and 4 December futures.
When the June futures contract closes on 17 June, there are still two months
before the FRA settles. The hedge needs to be maintained but if we replace the
sale of 3 now non-existent June contracts by the nearest available – that is, the
sale of 3 September contracts – there is a risk. Suppose that interest rates rise.
We will make a loss on the 5 v 10 FRA we have sold and a corresponding
gain on the futures hedge. If, however, the yield curve flattens somewhat at
the same time (shorter-term rates rise more than longer-term rates), we will
make less of a profit on the 3 new September contracts than we would have
made on the 3 June contracts. The hedge will not therefore be as effective.
This is a form of basis risk – that the movement in the instrument used as a
hedge does not match the movement in the instrument being hedged.
An attempt to hedge against this basis risk is as follows. If there is a flattening or steepening of the yield curve while the June contract does still exist,
any change in the September futures price is assumed to be approximately
equal to the average of the change in the June futures price and the December
futures price. For example, if the June price falls 10 ticks and the December
price rises 10 ticks (yield curve flattening), the September price is assumed
not to change. On this assumption, the following two positions would give
the same profit or loss as each other:
sell 6 September futures
or
sell 3 June futures and sell 3 December futures.
It follows that the following two positions would also give the same profit or
loss as each other:
sell 6 September futures and buy 3 December futures
or
sell 3 June futures.
In this way, if we must replace the sale of 3 June futures contracts (because
they no longer exist) by the sale of 3 September contracts, we should then
additionally sell a further 3 September contracts and buy 3 December contracts in an attempt to hedge the basis risk.
In Example 4.6 therefore, when the 3 June contracts expire, we replace
them by a further sale of 6 September futures and a purchase of 3 December
futures, to leave a net hedge then of short 16 September futures and
1 December futures.
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Part 2 · Interest Rate Instruments
TRADING WITH INTEREST RATE FUTURES
Basis
In practice, the actual futures price trading in the market is unlikely to be
exactly the same as the “fair” theoretical value which can be calculated
according to the underlying cash market prices. The difference between the
actual price and the theoretical “fair” price is termed the “basis”.
Suppose the following prices for a 3-month interest rate futures contract:
Actual futures price 94.40
Fair futures price
94.31 (based on a 5.69% forward-forward rate)
Implied cash price 93.90 (based on cash 3-month LIBOR of 6.10%)
“Basis” or “simple basis” is the difference between the price based on the
current cash rate and the actual price (93.90 – 94.40 = –0.50). This difference will tend towards zero on the last trading day for the futures contract.
“Theoretical basis” is the difference between the price based on the current cash rate and the fair price (93.90 – 94.31 = –0.41). This difference
depends on the calculation of the fair price and will also tend towards zero
on the last trading day for the futures contract.
“Value basis” is the difference between the fair and actual prices (94.31 –
94.40 = -0.09). If the value basis is temporarily large, arbitrageurs will trade
in such a way as to reduce it.
Clearly:
basis = theoretical basis + value basis
“Basis risk” is the risk arising from the basis on a futures position. Suppose for
example that on 1 April a futures trader sells a 1 v 4 FRA to a customer which
will settle on 4 May and that he hedges this by selling futures contracts for the
nearest futures contract – say for delivery on 18 June. The trader cannot be
perfectly hedged because on 4 May the cash market 3-month LIBOR against
which the FRA will be settled will not necessarily have moved since 1 May to
the same extent as the futures price. He thus has a basis risk.
Calculation
summary
Basis = implied cash price – actual futures price
Theoretical basis = implied cash price – theoretical futures price
Value basis = theoretical futures price – actual futures price
Volume and open interest
“Open interest” in a particular futures contract represents the number of
purchases of that contract which have not yet been reversed or “closed
out”. It is thus a measure of the extent to which traders are maintaining
their positions. The daily volume in a particular contract represents the
total number of contracts traded during the day. In both cases, contracts
74
4 · Interest Rate Futures
are not double-counted; either all the long positions or all the short positions are counted, but not both.
The development of volume and open interest are useful in assessing how
a futures price might move. If the futures price is rising, for example, and
volume and open interest are also rising, this may suggest that the rising price
trend will continue for the immediate future, as there is currently enthusiasm
for opening new contracts and maintaining them. If the open interest is
falling, however, this may suggest that traders are taking profits and not
maintaining their positions. Analogous interpretations are possible with a
falling futures price.
Speculation
As with an FRA, the most basic trading strategy is to use a futures contract
to speculate on the cash interest rate on maturity of the futures contract
being higher or lower than the interest rate implied in the futures price now.
If the trader expects interest rates to rise, he sells the futures contract; if he
expects rates to fall, he buys the futures contract.
As noted earlier, the profit or loss for a futures buyer is:
contract size ×
increase in price length of contract in months
×
100
12
Arbitrage
Example 4.7
Market prices are currently as follows. The futures delivery date is in 2 months’ time:
2 v 5 FRA
3 month futures
7.22 / 7.27%
92.67 / 92.68
A trader can arbitrage between these two prices by dealing at 7.27% in the FRA
and at 92.68 in the futures market. He buys the FRA and is therefore effectively
paying an agreed 7.27% in two months’ time. He also buys the futures contract
and is therefore effectively receiving (100 – 92.68)% = 7.32%. He has therefore
locked in a profit of 5 basis points.
In practice, Example 4.7 will be complicated by several factors in the same
way as in the previous section on hedging FRAs.
First, there is the problem that the FRA settlement is discounted but the
futures settlement generally is not. The trader needs to decrease slightly the
number of futures contracts traded to adjust for this. As we do not know the
discount factor in advance, we need to estimate it – for example, by using the
FRA rate itself.
Second, the period of the 2 v 5 FRA might be, for example, 92 days, while
the futures contract specification is effectively 90 days (for a currency where
the money market convention is ACT/360) and the two settlements will
reflect this. The trader needs to increase slightly the number of futures contracts traded to adjust for this.
75
Part 2 · Interest Rate Instruments
Combining these last two points, we could make an adjustment as follows:
notional amount of FRA ×
1
(1 + FRA rate × )
92
360
× 92
90
Third, the futures delivery date is unlikely to coincide with the start date
of the 2 v 5 FRA period, which gives rise to a basis risk. The trader therefore
also needs to adjust for this. If the nearest futures date is earlier than two
months, the trader could buy some futures for the nearest futures date and
some for the following date, in a ratio dependent on the time between the
two futures dates and the two-month date. If the nearest futures date is later
than two months, the trader could buy all the futures for that date and then
superimpose another futures trade as an approximate hedge against the basis
risk. As before, this hedge involves buying more futures for the nearest date
and selling futures for the following date.
Calendar spread
A spread is a strategy whereby the trader buys one futures contract and sells
another, because he expects the difference between them to change but does
not necessarily have any expectation about the whole yield curve moving in
one direction or the other. A calendar spread, for example, is used when the
trader expects the yield curve to change shape – that is, become more or less
positive – but does not have a view on rates overall rising or falling. This is
similar to the basis risk hedge already described, but using the spread to speculate rather than to hedge.
Example 4. 8
On 19 June, USD rates are as follows and a trader expects that the yield curve will
become even more negative:
3-month LIBOR:
6-month LIBOR:
9-month LIBOR:
September futures price:
December futures price:
6.375%
6.0625%
5.75%
94.34
95.03
If longer-term rates fall relative to shorter-term ones as expected, the December
futures price will rise relative to the September futures price. The trader therefore
sells September and buys December futures. In this case, he is “selling” the
spread. Suppose after one month, the prices are as follows:
2-month LIBOR:
5-month LIBOR:
8-month LIBOR:
September futures price:
December futures price:
6.75%
6.35%
5.87%
93.98
95.05
The trader can now reverse his position, having made the following profit and loss
on the two trades:
76
4 · Interest Rate Futures
September contract:
December contract:
Total profit:
+ 36 ticks (94.34 – 93.98)
+ 2 ticks (95.05 – 95.03)
+ 38 ticks × USD 25 = USD 950
The spread was successful because there was a shift in the yield curve as expected.
A longer-term spread can be taken if a trader has a view on short-term yields
compared with bond yields – for example, a spread between a 3-month
Eurodollar futures and long-term USD bond futures. In this case an adjustment has to be made for the difference in maturity of the underlying
instrument. Settlement on the short-term futures relates to a 90-day instrument, while settlement on the bond futures relates to a notional 15-year
bond. For a given change in yield therefore, there will be a far greater profit
or loss on the bond futures than on the short-term futures. To balance this,
the trader would buy or sell a much smaller notional amount of the bond
futures than of the short-term futures.
Cross-market spread
A spread can similarly be taken on the difference between two markets. For
example, if ECU interest rates are above DEM rates and a trader believes
that the spread between them will narrow, he could buy ECU futures and sell
DEM futures.
Strip trading
Just as we used a strip of futures to hedge an FRA in the last section, we
could use a strip to hedge an interest rate risk directly. If a trader, for example, buys a June futures and a September futures at the same time, he has
hedged against interest rates for six months rather than just for three months.
Example 4.9
A dealer expects to borrow DEM 10 million for six months from 19 June and
wishes to lock in a future borrowing rate.
Date:
Amount:
June futures price:
September futures price:
17 March
DEM 10 million
91.75 (implied interest rate: 8.25%)
91.50 (implied interest rate: 8.50%)
To hedge the borrowing, the dealer sells 10 June and 10 September DEM futures.
Three months later, the rates are as follows:
Date:
3-month LIBOR:
6-month LIBOR:
June futures EDSP:
September futures price:
17 June
9.00%
9.50%
91.00
90.22
The dealer now reverses the futures contracts and has the following profits:
77
Part 2 · Interest Rate Instruments
June contract:
September contract:
Total profit:
75 ticks (91.75 – 91.00)
128 ticks (91.50 – 90.22)
203 ticks
The total profit on the June / September strip is 203 ticks, in 3-month interest rate
terms. This is equivalent to 1.015% in 6-month interest rate terms. This profit is
received in June, but could be invested (say at LIBOR) until December when the
borrowing matures. This would give a profit of:
183
1.015% × (1 + 0.095 × 360
) = 1.064%
Therefore:
Effective borrowing rate = 6-month LIBOR – futures profit
= 9.50% – 1.064%
= 8.436%
The rate of 8.436% achieved in Example 4.9 comes from the same prices as
we used in Example 4.4. In that example, however, we calculated the FRA
rate slightly differently, as:
92
91
360
= 8.463%
) × (1 + 0.085 × 360
) – 1] × 183
[(1 + 0.0825 × 360
This demonstrates the effect of the various discrepancies mentioned after
Example 4.4.
The strip in Example 4.9 is a rather short strip. It is possible to buy or sell
a longer series of contracts to make a longer strip, which can be used, for
example, to hedge or arbitrage against a longer-term instrument. Another
strategy known as a “boomerang” involves buying a strip and simultaneously selling the same number of contracts all in the nearest date. This is a
type of spread, and, traded this way round, will make a profit, for example,
if a negative yield curve becomes more negative.
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4 · Interest Rate Futures
EXERCISES
37. You sell a June futures contract (3-month US dollars) at 94.20. You subsequently close out the position at 94.35. In which direction did you expect US
interest rates to move? What is your profit or loss?
38. Given the following 3-month Deutschemark futures prices, what is the implied
3 v 12 Deutschemark FRA rate? Assume that the June futures contract settlement date is exactly 3 months from spot settlement.
June
95.45
September 95.20
December 95.05
39. Given the futures prices in the previous question, what is the implied 4 v 8 FRA
rate? If you sell a 4 v 8 FRA to a customer, how would you hedge the position
using futures?
40. It is now June. You are overlent by DEM 10 million over the six-month period
from September to March (i.e. you have lent out DEM 10 million more over that
period than you have borrowed, and will need to borrow in due course to
cover this mismatch). Given the rates quoted to you, what is the cheapest way
to hedge your risk, assuming that all the dates match (i.e. the September
futures settlement is in exactly three months’ time from now, etc.)?
a.
Cash market
3 mths (92 days):
6 mths (183 days):
9 mths (273 days):
4.50%/4.65%
4.60%/4.75%
4.75%/4.90%
b.
FRAs
3 v 6:
6 v 9:
3 v 9:
4.86%/4.96%
4.90%/5.00%
4.97%/5.07%
c.
Futures
Sep:
Dec:
95.03
95.05
79
■
■
■
“The different conventions used
in different markets to relate
price and yield should not affect
the economics of an instrument.
The economics are determined
by what the price actually is and
what the future cashflows are.
From these, the investor can use
a consistent approach of his/her
choice to calculate yields
for comparison.”
80
5
Bond Market Calculations
Overview of capital market instruments
Features and variations
Introduction to bond pricing
Different yield measures and price calculations
A summary of the various approaches to price/yield
Duration, modified duration and convexity
Bond futures
Cash-and-carry arbitrage
Exercises
81
Part 2 · Interest Rate Instruments
OVERVIEW OF CAPITAL MARKET INSTRUMENTS
We have already considered short-term securities issued by borrowers in the
money market – treasury bills, CDs, commercial paper and bills of exchange.
Longer-term securities are considered as “capital market” instruments rather
than money market ones. Like commercial paper, capital market borrowing
normally involves lending directly from the investor to the borrower without
the intermediation of a bank. As a result of this disintermediation, only companies of high creditworthiness – or governments, quasi-governmental bodies
and supranational bodies – can usually borrow from the capital markets.
Those that do so, however, may raise finance more cheaply than they could
on the same terms from a bank.
A straightforward security issued as a medium-term borrowing, with a
fixed coupon paid at regular intervals, is generally called a bond – although a
medium-term CD issued by a bank is very similar. There is, however, a wide
range of variations on this basic theme.
Domestic, foreign and Eurobonds
As with money market instruments, there is a distinction between domestic
bonds (where the issuer sells the bond in its own country) and Eurobonds
(where the issuer sells the bond internationally). A further distinction is
drawn for foreign bonds, where a company issues a bond in a foreign country. For example, a US company might issue a bond in the domestic Japanese
market – a “Samurai” bond. Other examples of this are “Yankee” bonds
(foreign issues in the US domestic market), “Bulldog” bonds (in the UK),
“Matador” bonds (in Spain), and “Alpine” bonds (in Switzerland).
Eurobonds are issued in bearer form – investors do not have to be registered as in the domestic US bond markets, for example. Ownership is
evidenced by physical possession and the interest is payable to the holder presenting the coupon, which is detachable from the bearer bond. This is clearly
an advantage to an investor who wishes to remain anonymous. Interest on
Eurobonds is quoted on a 30(E)/360 basis (see later for an explanation of the
various day/year conventions) and paid gross of tax.
As in other markets, there is an important distinction between a “Eurobond”
(a bond issued internationally) and a “euro bond” (a bond denominated in
euros, whether issued “domestically” in the euro zone, or internationally).
Government bond markets
Domestic debt markets are usually dominated by government debt for two
reasons. First, government debt outstanding is usually large in relation to the
market as a whole and therefore offers good liquidity. Second, government
debt issued in the domestic currency is usually considered virtually riskless,
82
5 · Bond Market Calculations
because the government can always print its own money to redeem the issue.
Its debt therefore provides a good benchmark for yields. The following are a
few of the important markets:
USA
US government issues with an original maturity between one year and ten
years are called “treasury notes”. Issues with an original maturity longer
than ten years (in practice up to 30 years) are called “treasury bonds”. The
difference in name does not affect calculations for these bonds. All pay
semi-annual coupons and have both the accrued coupon and price calculated on an ACT/ACT basis (see later in this chapter for an explanation of
the different calculation bases).
In addition to US treasury bonds, there is a large market in bonds issued
by US federal agencies (generally supported by the US government), such as
the Federal National Mortgage Association (FNMA or “Fanny Mae”),
Student Loan Marketing Association (SLMA or “Sally Mae”), Federal Home
Loan Mortgage Corporation (FHMC or “Freddie Mac”) and Government
National Mortgage Association (GNMA or “Ginny Mae”). Coupons and
price are calculated on a 30(A)/360 basis.
UK
UK government securities are called gilt-edged securities or “gilts”.
Conventional gilts are generally called “shorts” if they have a remaining
maturity up to five years, “mediums” between five and fifteen years, and
“longs” over fifteen years. Almost all gilts pay coupons semi-annually,
although there are a few with quarterly coupons. Some are index-linked,
where both the coupon and redemption amount paid depend on the inflation
rate. Accrued coupon and price have both been calculated on an ACT/365
basis prior to 1998, with the price / yield calculation changing to ACT/ACT
in December 1997 when strip trading began and the accrued coupon calculation changing to ACT/ACT in late 1998.
Most gilts are conventional bonds with a fixed maturity. Some may be
redeemed by the government early, and some (“convertibles”) may be converted by the holder into other specific issues. There are a few irredeemable
gilts, although these are no longer issued.
Germany
German government bonds pay annual coupons, with accrued coupon and
price both calculated on a 30(E)/360 basis. Important bonds are Bunds
(Bundesanleihen), normally with an original maturity of ten years, BOBLS or
OBLs (Bundesobligationen), with maturities up to five years, and Schätze
(federal treasury notes) with two-year maturities.
83
Part 2 · Interest Rate Instruments
France
French government bonds pay annual coupons, with accrued coupon and
price both calculated on an ACT/ACT basis. The most important bonds are
BTANs (bons du trésor à taux fixe et intérêt annuel), with original maturities
of between two and five years, and OATs (obligations assimilables du trésor)
with original maturities of between seven and thirty years.
FEATURES AND VARIATIONS
What we have described so far are essentially straightforward bonds with a
fixed coupon and a fixed maturity date when all the bond is redeemed (that
is, repaid). There are several variations available.
Floating rate note (FRN)
An FRN is a bond whose coupon is not fixed in advance, but rather is
refixed periodically on a “refix date” by reference to some floating interest
rate index. In the Euromarkets, this is often some fixed margin over sixmonth LIBOR.
Essentially, investing in an FRN is equivalent to investing in a short-term
money market instrument such as a six-month CD, and then reinvesting the
principal in a new CD on a rolling basis as the CD matures.
Index-linked bonds
With an index-linked bond, the coupon, and possibly the redemption
amount, are linked to a particular index rather than fixed. For example,
some governments issue index-linked bonds where the coupon paid is a certain margin above the domestic inflation index. Index-linked bonds issued by
companies are often linked to stock indexes or commodity price indexes.
Zero-coupon bonds
Zero-coupon bonds are bonds that make no interest payments. Similar to commercial paper or treasury bills in the money market, the price must be less than
the face value, so that they are sold at a discount to their nominal value.
The only cashflows on a zero-coupon bond are the price paid and the
principal amount received at maturity, so that the investor’s return is represented by the relationship between these two amounts. With a “normal”
coupon-bearing bond, the investor is vulnerable to the risk that, by the time
he/she receives the coupons, interest rates have fallen so that he/she can only
reinvest the coupons received at a lower rate. Whether the reinvestment rate
has in fact fallen or risen, the final outcome for the investor is not known
84
5 · Bond Market Calculations
exactly at the beginning. With a zero-coupon bond however, the outcome is
known exactly because there are no coupons to reinvest. Because of this certainty, investors may accept a slightly lower overall yield for a zero-coupon
bond. Differences in tax treatment between capital gains / losses and coupon
income may also affect the attractiveness of a zero-coupon bond compared
with a coupon-bearing bond.
Strips
The process of stripping a bond is separating all the cashflows – generally a
series of coupon payments and a redemption payment – and then trading
each cashflow as a separate zero-coupon item. Various governments (US,
UK, German and French, for example) facilitate the trading of their securities
as strips in this way. Before government securities were officially strippable
however, strips were created by investment banks. The bank sets up a special
purpose vehicle to purchase the government security, holds it in custody, and
issues a new stripped security in its own name on the back of this collateral.
Amortisation
A straightforward bond has a “bullet” maturity, whereby all the bond is
redeemed at maturity. An alternative is for the principal amount to be repaid
in stages – “amortised” – over the bond’s life.
Perpetual bonds
A perpetual bond is one with no redemption date. Most such bonds have
been FRNs issued by banks, although there are some government perpetuals,
such as the “War Loan” UK gilt.
Calls and puts
Bonds are often issued with options for the issuer to “call” (i.e. redeem) the
bond prior to maturity. This often requires that the redemption amount is
higher than it would be at maturity. This option is particularly helpful with
fixed rate bonds, to protect the issuer from paying too much if market interest rates fall after the bond has been issued. This is because he can then
redeem the bond early and issue a new one with a lower coupon.
Bonds can also be issued with an option for the investor to “put” (i.e.
require redemption on) the bond before maturity.
Bond warrants
A warrant attached to a bond is an option to buy something – generally more
of the same bond or a different bond.
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Part 2 · Interest Rate Instruments
Medium-term note (MTN)
An MTN is a hybrid between commercial paper and a bond. Like commercial paper, an MTN is issued continually rather than as a one-off. Like a
bond, it has a maturity over one year and pays a coupon, either fixed- or
floating-rate. The interest calculation may be either on a money market basis
– for example ACT/360 for US domestic MTNs – or on a bond basis –
30(E)/360 for Euro-MTNs.
Asset-backed securities
In a straightforward bond, the investor is relying on the issuer’s overall creditworthiness for payment of the bond’s coupons and repayment of the
principal. With an asset-backed security however, the bond is collateralised
by a specific asset or pool of assets which generate the necessary cashflows.
In a mortgage-backed security, for example, a collection of property mortgages may be pooled together. The investor buys a security which is issued by a
special-purpose company. The security is however collateralised specifically by
the pool of mortgages so that the investor’s risk is that of the original underlying
mortgage transactions. Each of these in turn is collateralised by the property in
question. Ultimately therefore, the bond market investor is buying a bond with
property values collateralising the risk. As each individual mortgage is repaid,
the mortgage-backed security is amortised to the extent of the principal amount
of that individual mortgage. Whether the amortisation is applied to each individual investor’s bond holding pro rata, or to particular holdings at random,
depends on the security’s structure. Either way, it is impossible for the investor
to predict his/her cashflows precisely, regardless of whether the security is fixedrate or floating-rate. In assessing the yield on such a security, the investor must
therefore make assumptions about the likely pattern of amortisation, based on
historic comparisons and interest rate expectations.
INTRODUCTION TO BOND PRICING
We have already seen that for a given yield, any future cashflow C has a present value equal to:
C
(1+i)N
where i is the annual yield and N is the number of years ahead that the cashflow occurs.
Given a series of cashflows – some of which could be negative and some
positive – the net present value of the whole series is the sum of all the present values.
The principles of pricing in the bond market are the same as the principles
of pricing in other financial markets – the total price paid for a bond now is
86
5 · Bond Market Calculations
the net present value now of all the future cashflows which arise from holding the bond. The price is expressed as the price for 100 units of the bond.
In general therefore, the theoretical all-in price P of a straightforward
bond should be given by:
P = ∑k
Ck
dk × n
year
Calculation
summary
(1 + ni )
where:
Ck
dk
i
year
=
=
=
=
the kth cashflow arising
number of days until Ck
yield on the basis of n payments per year
number of days in the conventional year.
The important thing to note here is the concept that the all-in price of a bond
equals the NPV of its future cashflows.
All-in price of a bond = NPV of the bond’s future cashflows
Key Point
Because the price is the net present value, the greater the yield used to discount the cashflows, the lower the price.
A bond’s price falls as the yield rises and vice versa
Key Point
There are four small but significant differences in practice between calculations for a bond price and the price of a money market instrument such as a
medium-term CD. These differences are helpful in understanding the ideas
behind bond pricing:
1. The coupon actually paid on a CD is calculated on the basis of the exact
number of days between issue and maturity. With a bond, the coupons
paid each year or half-year (or occasionally each quarter) are paid as fixed
“round” amounts. For example, if a 10 percent coupon bond pays semiannual coupons, exactly 5 percent will be paid each half-year regardless of
the exact number of days involved (which will change according to weekends and leap years, for example).
Bond coupons are paid in round amounts, unlike CD coupons which
are calculated to the exact day
Key Point
87
Part 2 · Interest Rate Instruments
2. When discounting to a present value, it is again assumed that the time
periods between coupons are “round” amounts – 0.5 years, 1 year, etc.,
rather than an odd number of days. For this purpose, the first outstanding
coupon payment is usually assumed to be made on the regular scheduled
date, regardless of whether this is a non-working day.
Key Point
For straightforward bonds, pricing conventionally assumes that
periods between coupons are regular
3. When discounting back to a present value from the first outstanding
coupon payment date, the price calculation is made on the basis of compound interest rather than simple interest. Suppose, for example, there is a
cashflow of 105 occurring 78 days in the future, the yield is 6 percent and
the year-count basis is 360. The present value calculation for a CD would
105
be
, which uses the 6 percent yield for 78 days on a simple
ui
(1 + 0.06 × ´–
¥π)
105
basis. The corresponding calculation for a bond would be
ui
¥π which
(1 + 0.06)´–
ui
compounds the 6 percent yield for ´–
¥π of a year.
Key Point
Bond pricing conventionally assumes
compound discounting to NPV
4. The day/year count basis for money market instruments and bonds is generally different. The first have been described earlier. The day/year counts
for bonds are described later in this chapter.
Given these differences, it is possible to express the equation for a bond price
given earlier as follows:
Calculation
summary
P=
100
(1
+ ni W
)
[
(
1–
R
×
n
(
1
)
))
(1 + ni )
1–
N
1
(1 + ni
+
1
]
(1 + ni )N–1
where: R = the annual coupon rate paid n times per year
W = the fraction of a coupon period between purchase and
the next coupon to be received
N = the number of coupon payments not yet paid
i = yield per annum based on n payments per year.
Despite the simplifying assumptions behind this formula, it is important
because it is the conventional approach used in the markets. Adjustments to
88
5 · Bond Market Calculations
the formula are of course necessary if there are different cashflows to be discounted – for example, an unusual first coupon period which gives an odd
first coupon payment, early partial redemptions of the bond or changes in
the coupon rate during the bond’s life. Even with these adjustments, the
market approach is still generally to calculate the total price as the NPV
assuming precisely regular coupon periods and certain day/year conventions.
It is clearly possible to calculate a price without making these assumptions
– that is, to use the formula:
Ck
P = ∑k
(
dk × n
year
)
1 + ni
with the exact time periods between cashflows and a consistent day/year
basis for all types of bonds. For bonds of short maturity, the result can be
significantly different from the conventional formula and this approach is
clearly more satisfactory when comparing different bonds. In the UK gilt
market, for example, some market participants quote yields taking into
account the exact number of days between the actual cashflows. Some also
use a year basis of ACT/365q-® to allow for the average effect of leap years.
Accrued interest
The price we have calculated so far is in fact known as the “dirty” price of
the bond and represents the total amount of cash paid by the buyer. From
the seller’s point of view, however, he expects to receive “accrued” coupon
on the bond. The accrued coupon is the coupon which the seller of a bond
has “earned” so far by holding the bond since the last coupon date. He feels
he is entitled to this portion of the coupon and therefore insists on the bond
buyer paying it to him. The buyer, however, will pay no more than the NPV
of all the future cashflows. Therefore the total price paid is the dirty price
but this is effectively considered as two separate amounts – the “clean” price
and the accrued coupon. The price quoted in the market is the “clean” price,
which is equal to dirty price minus the accrued coupon. In the market generally, accrued coupon is often called accrued interest.
Example 5.1
A bond pays a 9% coupon annually. Maturity is on 15 August 2003. The current
market yield for the bond is 8%. Interest is calculated on a 30(E)/360 basis (see
later in this section for an explanation of this convention). What are the accrued
coupon, dirty price and clean price for settlement on 12 June 1998?
Time from 15 August 1997 (the last coupon date) to 12 June 1998 is 297 days on a
30(E) basis:
Accrued coupon = 9 ×
297
= 7.4250
360
Time from 12 June 1998 to 15 August 1998 is 63 days on a 30(E) basis:
89
Part 2 · Interest Rate Instruments
Dirty price =
100
63
1.08 360
(
× 0.09 ×
(1 – 1.081 6)
1
+
1
5
1.08
1
–
( 1.08)
)
= 111.4811
Clean price = 111.4811 – 7.4250 = 104.06
1.08 ENTER 6 ■ ∧ ■ 1/x 1 ■ xy –
1.08 ■ 1/x 1 ■ xy – ÷
.09 ×
1.08 ENTER 5 ■ ∧ ■ 1/x +
100 ×
1.08 ENTER 63 ENTER 360 ÷ ■ ∧ ÷
9 ENTER 297 × 360 ÷
–
Calculation
summary
(Dirty price)
(Accrued interest)
(Clean price)
Dirty price = NPV of cashflows
Accrued coupon = proportion of coupon since last coupon payment
Clean price = dirty price – accrued coupon
Clean bond prices are generally quoted in terms of the price per 100 units of
the bond, often to two decimal places. US bonds are, however, generally
quoted in units of _
´q∑. Thus a price of 95–17 for a US treasury bond means
_
´∑ (= 95.53125) per $100 face value, rather than $95.17 per $100 face
$95qu
value. This is sometimes refined further to units of ¥_q® by use of “+” and “–”.
_
¥® = 95.546875. Option prices on US govThus a price of 95–17+ means 95et
q®.
ernment bonds are quoted in units of ¥_
Coupon dates
Apart from the first coupon period or the last coupon period, which may
be irregular, coupons are generally paid on regular dates – usually annual
or semi-annual and sometimes quarterly. Thus semi-annual coupons on a
bond maturing on 17 February 2015 would typically be paid on 17 August
and 17 February each year. If a semi-annual bond pays one coupon on 30
April for example (that is, at month-end), the other coupon might be on 31
October (also month-end) as with a US treasury bond, or 30 October as
with a UK gilt.
Even though the previous coupon may have been delayed – for example,
the coupon date was a Sunday so the coupon was paid the following day –
the accrual calculation is taken from the regular scheduled date, not the
actual payment date. Also, the accrued interest is calculated up to a value
date which in some markets can sometimes be slightly different from the
settlement date for the transaction. This does not affect the total dirty price
paid. Note that in some markets, if the scheduled coupon payment date is a
Saturday, the payment is actually made on the previous working day,
rather than on the next working day as is the more usual convention.
90
5 · Bond Market Calculations
Ex-dividend
When a bond is bought or sold shortly before a coupon date, the issuer of the
bond generally needs some days to change the records in order to make a
note of the new owner. If there is not enough time to make this administrative change, the coupon will still be paid to the previous owner.
The length of time taken varies widely between different issuers. The
issuer pays the coupon to the holder registered on a date known as the record
date. This is therefore the last date on which a bond transaction can be settled in order for the new owner to be recorded in time as entitled to the
coupon, and a bond sold up to this date is said to be “cum-dividend”. A
bond sold for settlement after this date is said to be sold “ex-dividend” or
“ex-coupon”. In some cases it is possible to sell a bond ex-dividend before
the normal ex-dividend period.
If a bond sale is ex-dividend, the seller, rather than needing to receive
accrued interest from the buyer, will need to pay it to the buyer – because the
final days of the coupon period which “belong” to the buyer will in fact be
paid to the seller. At the ex-dividend point therefore, the accrued interest
becomes negative. In this case, the accrued interest is calculated from value
date to the next scheduled coupon date (rather than the next actual coupon
payment date if that is different because of a non-working day).
Example 5.2
Consider a UK gilt with a coupon of 7.3% and maturity 17 August 2005, purchased
for settlement on 13 August 1998 at a price of 98.45. Assume the record date is 5
working days before the coupon date.
The accrued interest is:
–4
× 7.3 = –0.08
365
The all-in price is therefore 98.45 – 0.08 = 98.37
Accrued coupon = 100 × coupon rate ×
days since last coupon
year
Calculation
summary
For ex-dividend prices, accrued coupon is negative:
Accrued coupon = –100 × coupon rate ×
days to next coupon
year
Day/year conventions
Fractional periods of a year for price / yield calculations and accrued coupon
are calculated according to different conventions in different markets. As in
the money market, these conventions are generally expressed in the form
“days/year” where “days” is the conventional number of days in a particular
period and “year” is the conventional number of days in a year.
91
Part 2 · Interest Rate Instruments
Calculation of days in the period
ACT The actual number of calendar days in the period.
30(E) To calculate the number of days between two dates d1 / m1 / y1 and d2 /
m2 / y2 , first make the following adjustments:
If d1 is 31, change it to 30.
If d2 is 31, change it to 30.
The number of days in the period between the two dates is given by:
(y2 – y1) × 360 + (m2 – m1) × 30 + (d2 – d1)
For example there are 5 days between 27 February and 2 March and
33 days between 27 February and 31 March.
30(A) This is similar to 30(E), but with the following difference:
If d2 is 31 but d1 is not 30 or 31, do not change d1 to 30.
The number of days in the period between the two dates is again given by:
(y2 – y1) × 360 + (m2 – m1) × 30 + (d2 – d1)
For example, there are 5 days between 27 February and 2 March and
34 days between 27 February and 31 March.
Calculation of year basis
365
Assume that there are 365 days in a year.
360
Assume that there are 360 days in a year.
ACT Assume that the number of days in a year is the actual number of days
in the current coupon period multiplied by the number of coupon payments per year.
The four combinations used in the bond market (in addition to ACT/360
used in many money markets as discussed earlier) are:
ACT/365 Sometimes called “ACT/365 fixed”. Used for Japanese government
bonds and, prior to late 1998, for accrued interest on UK gilts.
ACT/ACT Used for US treasury notes and bonds, which always pay coupons
semi-annually, and results in a value for the year of 362, 364, 366
or 368 (twice the coupon period of 181, 182, 183 or 184). It is
also used for French government bonds, which pay coupons annually, resulting in a value for the year of 365 or 366. It is also the
method for accrued interest on UK gilts after late 1998.
30(E)/360 Sometimes called “360/360”. Used for Eurobonds and some
European domestic markets such as German government bonds.
30(A)/360 Used for US federal agency and corporate bonds.
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5 · Bond Market Calculations
In general, the convention for accrued interest in a particular market is the
same as the convention used in that market for calculating the fraction of a
year for the price / yield formula. This is not always so, however. In Italy, for
example, accrued interest is calculated on a 30(E)/360 basis, but the price is
calculated on an ACT/365 basis. In Spain, on the other hand, accrued interest is ACT/ACT and the price is ACT/365.
Note that, because coupons are paid in “round” amounts, it is possible for
the accrued coupon to be greater than the actual coupon payable for the
period. For example, if coupons are paid semi-annually on an ACT/365
basis, the interest accrued from a 15 March coupon date to 14 September
would be coupon × –
´qie
¥† , which is greater than the coupon × q-∑ payable. This
possibility depends on the ex-dividend period for the bond.
Example 5.3
Consider a bond whose previous coupon was due on 15 January 1999 and whose
next coupon is due on 15 July 1999. The number of calendar days in the current
coupon period is 181. The day/year calculation under the various conventions is
shown below for accrued interest from 15 January up to 30 March, 31 March and 1
April respectively:
ACT/365
ACT/360
30(E)/360
30(A)/360
ACT/ACT
30 March
31 March
1 April
74/365
74/360
75/360
75/360
74/362
75/365
75/360
75/360
76/360
75/362
76/365
76/360
76/360
76/360
76/362
We have given a list of the conventions used in some important markets in
Appendix 1.
Using an HP calculator
The HP17 and HP19 calculators have inbuilt functions specifically for calculating clean bond prices and yields. They allow for coupons to be paid
annually or semi-annually and also for the day/year counts to be 30(A)/360
or ACT/ACT. Provided that neither the settlement date nor the next coupon
date is the 31st day of a month, 30(A)/360 is the same as 30(E)/360. Also,
provided that the current coupon period does not include 29 February,
ACT/ACT annual is the same as ACT/365 annual. The calculator cannot
however calculate on an ACT/365 semi-annual basis.
HP calculator example
We can repeat Example 5.1 using the HP bond function as follows:
93
Part 2 · Interest Rate Instruments
HP19BII
FIN BOND
TYPE 360 ANN EXIT
12.061998 SETT
15.082003 MAT
9 CPN%
MORE 8 YLD%
PRICE
ACCRU
+
(Set for 30/360, annual coupons)
(Settlement date)
(Maturity date)
(Coupon)
(Yield)
(Clean price)
(Accrued interest)
(Dirty price)
Similarly to the TVM function of the calculator, it is possible to calculate
the clean price from the yield or the yield from the clean price. It is also possible to allow for a redemption amount different from the normal 100 by
entering the appropriate value as a “call” amount – i.e. the amount which
the issuer must pay on redemption if he wishes to call the bond on the date
entered as the maturity date.
HP calculator example
A bond pays a 6.5% coupon semi-annually. Maturity is on 22 July 2015. The bond
will be redeemed at a rate of 105 per 100. The current (clean) price for the bond for
settlement on 27 March 1998 is 97.45. Interest and price / yield calculations are
both on a semi-annual ACT/ACT basis. What is the yield of the bond?
Answer: 6.91%
HP19BII
FIN BOND
TYPE A/A SEMI EXIT
27.031998 SETT
22.072015 MAT
6.5 CPN%
105 CALL
MORE 97.45 PRICE
YLD%
(Set for ACT/ACT, semi-annual)
(Settlement date)
(Maturity date)
(Coupon)
(Redemption amount per 100)
(Clean price)
(Yield)
Note that it is probably useful to reset the call amount to 100 after such a
calculation, to avoid forgetting this next time!
As already mentioned, some bonds, such as Spanish and Italian bonds, for
example, calculate accrued interest on one day/year basis but calculate the
dirty price from the future cashflows on a different day/year basis. The HP
bond function is not able to calculate with a mixture in this way, and the
numbers must be manipulated to get round the problem. The exercises at the
end of the chapter include some examples of this. The procedures necessary
are as follows:
To calculate the clean price from the yield
• Set the calculator for the day/year basis used for the price / yield calculation.
94
5 · Bond Market Calculations
• Calculate the clean price and accrued interest as usual. Add together to
•
•
give the true dirty price.
Reset the calculator for the day/year basis used for the accrued interest.
Calculate the conventional accrued interest and subtract from the dirty
price to give the clean price.
To calculate the yield from the clean price
• Set the calculator for the day/year basis used for the accrued interest
calculation.
• Calculate the accrued interest as usual. Add to the known clean price to
give the true dirty price.
• Reset the calculator for the basis used for the price / yield calculation.
• Recalculate an adjusted accrued interest and subtract from the true dirty
price to give an adjusted clean price.
• Use this adjusted clean price to calculate the yield.
DIFFERENT YIELD MEASURES AND PRICE CALCULATIONS
Yield to maturity
We have so far considered how to calculate a bond’s price if we know its
yield. This is the same as calculating an NPV given a rate of discount.
Calculating the yield if we know the price is the same as calculating the internal rate of return of all the cashflows including the price paid. As noted in
Chapter 1, there is no formula for this calculation. Instead, it is necessary to
use the price formula and calculate the yield by iteration – estimate a yield,
calculate the price based on this estimate, compare with the actual price,
adjust the yield estimate, recalculate the price, etc.
The yield we have used is known as the yield to maturity (sometimes
YTM). It is also known simply as “yield,” “redemption yield” or “gross
redemption yield” (GRY) because it is the yield to the redemption date
assuming all cashflows are paid gross (without deduction of tax).
Some bonds make partial redemptions – that is, the principal is repaid in
stages rather than all at maturity. Using the same approach as we have so far
requires that all the cashflows, including the partial redemptions, are discounted at the yield to give the dirty price. In this case, the yield is sometimes
known as “yield to equivalent life.”
The yield to maturity has the same disadvantage that we considered in
Chapter 1; it assumes that all cashflows can be reinvested at the same rate.
Consider, for example, a 7-year bond with annual coupons of 10 percent, a
price of 95.00 and an annual yield of 11.063 percent. This means that if all
the cashflows are discounted at 11.063 percent, they have an NPV of 95.
Equivalently, if all the cashflows received over the bond’s life can be reinvested to maturity at 11.063 percent, the final internal rate of return will also
be 11.063 percent.
95
Part 2 · Interest Rate Instruments
In practice, reinvestment rates will be different. However, given that a bond
does have a market price, an investor wishes to be told, in summary, what rate
of return this implies. There are as many answers to the question as there are
assumptions about reinvestment rates. One possibility would be to calculate
the current market forward-forward rates at which all the coupon cashflows
could be reinvested. In practice, the conventional summary answer given to the
question is the internal rate of return – i.e. the yield to maturity.
Yield vs. coupon
It is intuitively reasonable that when a bond’s yield is the same as its coupon, the
bond’s price should be par (that is, 100) – because the bond’s future cashflows
are created by applying an interest rate to the face value of 100 and discounting
back again to an NPV at the same rate should arrive back at 100.
Similarly, as the yield rises above the coupon rate, the NPV will fall and
vice versa. Therefore:
Key Point
Generally, if a bond’s price is greater than par, its yield is less than
the coupon rate, and vice versa
Although this intuitive result is almost true, the price is not in fact exactly
100 when the yield is equal to the coupon, except on a coupon date. This is
because accrued interest is calculated on a simple interest basis and price on
a compound interest basis.
Example 5.4
Consider the same bond as in Example 5.1, but assume the yield is now 9%. What
is the clean price?
As before, accrued coupon = 9 ×
Dirty price =
100
1.09
63
360
(
× 0.09 ×
297
= 7.4250
360
(1 – 1.091 6)
+
1
(1 – 1.09
)
)
1
= 107.3685
1.095
Clean price = 107.3685 – 7.4250 = 99.94
FIN BOND TYPE 360 ANN EXIT
12.061998 SETT
15.082003 MAT
9 CPN%
MORE 9 YLD%
PRICE
In Example 5.4, if the clean price were exactly 100, the yield would in fact be
8.986%.
This calculation is complicated further, of course, when the day/year basis
for the price / yield calculation is different from the day/year convention for
the accrued interest. In general, however:
96
5 · Bond Market Calculations
On a non-coupon date, if a bond is priced at par, the yield is slightly
lower than the coupon rate
Key Point
The effect increases as the settlement date moves away from the coupon
dates and is greater for bonds of short maturity.
Current yield
A much more simple measure of yield, which can be calculated easily, is the
current yield. This ignores any capital gain or loss arising from the difference
between the price paid and the principal amount received at redemption. It
also ignores the time value of money. Instead it considers only the coupon
income as a proportion of the price paid for the bond – essentially considering the investment as an indefinite deposit:
Current yield =
Calculation
summary
coupon rate
clean price
100
Simple yield to maturity
Simple yield to maturity does take the capital gain or loss into account as
well as the coupon but, like current yield, ignores the time value of money.
The capital gain or loss is amortized equally over the time left to maturity:
The simple yield to maturity is used in the Japanese bond market.
Simple yield to maturity =
(
coupon rate +
)
redemption amount – clean price
years to maturity
Calculation
summary
clean price
100
Example 5.5
For a 7-year bond paying annual 10% coupons and with a price of 95.00, what are
the yield to maturity, current yield and simple yield to maturity?
Yield to maturity = 11.06%
Current yield =
10%
95.00
100
= 10.53%
Simple yield to maturity =
10 + ( 100 7– 95 )
(
95.00
100
)
% = 11.28%
97
Part 2 · Interest Rate Instruments
FIN TVM
7N
95 +/- PV
10 PMT
100 FV
I%YR
10 ENTER .95 ÷
100 ENTER 95 – 7 ÷ 10 + .95 ÷
(Yield to maturity)
(Current yield)
(Simple yield to maturity)
Figure 5.1 compares the different measures for the same bond at different prices.
Fig 5.1
Comparison of yield measures for a 7-year 10% coupon bond
20%
Simple yield to maturity
Yield
15%
Current yield
10%
Yield to maturity
5%
0%
75
80
85
90
95
100 105 110 115 120 125 130
Price
Yield in a final coupon period
When a bond has only one remaining coupon to be paid (at maturity), it looks
very similar, in cashflow terms, to a short-term, money-market instrument. For
this reason, yields for such bonds are sometimes quoted on a basis comparable
to money market yields. This means that the future cashflow is discounted to a
present value (the price) at a simple rate rather than a compound rate – but still
using the day/year basis conventional for that particular bond market.
Example 5.6
Consider the following bond:
Coupon:
Maturity date:
Settlement date:
Clean price:
Price / yield calculation basis:
Accrued interest calculation basis:
8% semi-annual
20 October 2000
14 August 2000
100.26
ACT/ACT
ACT/ACT
The current coupon period from 20 April to 20 October is 183 days
Therefore the accrued interest is 8 ×
98
116
= 2.5355
366
5 · Bond Market Calculations
Therefore the dirty price is 100.26 + 2.5355 = 102.7955
(a) Following the logic of usual bond pricing, the price / yield equation would be:
dirty price =
final cashflow
days
(1 + yield) year
This can be manipulated to become:
yield =
=
( finaldirtycashflow
price )
104
( 102.7955
)
366
67
year
days
–1
– 1 = 6.57%
(b) Using simple interest, however, the result would be:
yield =
=
year
– 1) ×
( finaldirtycashflow
price
days
104
366
– 1) ×
= 6.40%
( 102.7955
67
Method (b) is assumed by the HP calculator. It is used in the market, for example,
for US treasury bonds (on an ACT/ACT basis), but not generally for Eurobonds.
104 ENTER 102.7955 ÷ 366 ENTER 67 ÷ ■ ∧ 1 –
104 ENTER 102.7955 ÷ 1 – 366 × 67 ÷
(a)
(b)
Alternative yield calculation in a final coupon period
i=
[
Calculation
summary
]
total final cashflow including coupon
year
–1 ×
dirty price
days to maturity
where days and year are measured on the relevant bond basis
Bond-equivalent yields for treasury bills
In the previous section we considered what is the yield of a bond in its last
coupon period, calculated by a method which enables comparison with a
money market instrument. In the US market, the reverse is also considered:
what is the yield of a treasury bill calculated by a method which enables
comparison with a bond which will shortly mature? The bond-equivalent
yield of a treasury bill is therefore the coupon of a theoretical US treasury
bond, trading at par, with the same maturity date, which would give the
same return as the bill.
If the bill has 182 days or less until maturity, the calculation for this is the
usual conversion from discount to yield, except that it is then quoted on a
365-day basis:
i=
D
(
days
1–D×
360
)
× 365
360
99
Part 2 · Interest Rate Instruments
where: D
= discount rate (on a 360-day basis)
days = number of days until maturity
i
= the bond-equivalent yield we are trying to calculate
If 29 February falls during the 12-month period starting on the purchase
date, 365 is conventionally replaced by 366.
If the bill has more than 182 days until maturity, however, the calculation
must take account of the fact that the equivalent bond would pay a coupon
during the period as well as at the end. The amount of the first coupon is
taken to be the coupon accrued on the bond between purchase and coupon
date (which is half a year before maturity). This coupon is:
P×i×
(
365
2
365
days –
=P×i×
)
1
–
(days
365 2)
where: P = the price paid for the bond ( = its par value)
If this coupon is reinvested at the same yield i, then at maturity it is worth:
P×i×
1
i
–
× 1+ )
(days
365 2 ) (
2
The bond also returns at maturity the face value P and the final coupon – a
total of:
(
P× 1+
i
2
)
Adding together these amounts, the total proceeds at maturity are:
(
P× 1+
) (
(
i
days 1
× 1+i×
–
2
365 2
))
Since the return on this theoretical bond is the same as the return on the treasury bill, these total proceeds must be the face value F of the bill paid on
maturity, and the price paid P must be the same as the discounted value paid
for the bill. Thus:
1
–
( 2i ) × (1 + i × (days
365 2))
days
and P = F × (1 – D ×
360 )
F=P× 1+
Therefore:
i2 ×
100
(
)
(
days 1
2 × days
–
+i×
+2× 1–
365 2
365
1
(
1–D×
)
)
days
360
=0
5 · Bond Market Calculations
Solving for a quadratic equation, this gives the formula shown below.
Again, if 29 February falls in the 12-month period starting on the purchase
date, 365 is conventionally replaced by 366.
Calculation
summary
Bond-equivalent yield for US treasury bill
If 182 days or less to maturity:
i=
D
1–D×
days
360
365
360
×
If more than 182 days to maturity:
–
days
365
i=
+
(
2
( )
days
365
+2×
(
days 1
–2
365
(
days
360
–
1
2
)×
((
∑-q
1
1–D×
)
days
360
))
–1
)
If 29 February falls in the 12-month period starting on the purchase date,
replace 365 by 366.
It should be noted that if there happen to be a treasury bill and a treasury
bond maturing on the same day in less than 182 days, the bond-equivalent
yield for the bill is not exactly the same as the yield quoted for a bond in its
final coupon period, even though this is intended to take the same approach
as money market instruments. Example 5.7 demonstrates this.
Example 5.7
Consider a US treasury bill maturing on 20 October 2000 and quoted at a discount
rate of 6.2229% for settlement 14 August 2000. (The discount rate would not normally be quoted to that level of precision, but we need this for a comparison with
the previous example.)
The bond-equivalent yield for this bill is:
6.2229%
67
(1 – 0.062229 × 360
)
×
365
= 6.38%
360
Suppose that we purchase face value $10,400 of the bill. The price paid would be:
(
$10,400 × 1 – 0.062229 ×
67
= $10,279.55
360
)
The cashflows for this bill are exactly the same as if we buy face value $10,000 of
the bond in the previous example; the final proceeds are principal plus a semiannual coupon and the dirty price paid is 102.7955. The yield quoted for that bond
however was 6.40%, because the year basis was 2 × 181 days.
0.062229 ENTER 67 × 360 ÷ 1 – +/- 6.2229 ■ xy ÷ 365 × 360 ÷
101
Part 2 · Interest Rate Instruments
Money market yield
The difference in price / yield conventions between instruments such as a
long-term CD and a bond makes comparison between them difficult. An
investor may therefore wish to bring them into line by calculating a money
market yield for a bond.
From earlier, we saw that the differences between the two approaches
(apart from the fact that coupons on bonds are paid in round amounts and
those on CDs are not) are:
1. CD price calculations use exact day counts rather than assume regular
time intervals between coupon payments.
2. CDs calculate the final discounting from the nearest coupon date back to
the settlement date using simple interest rather than compound interest.
3. CDs and bonds generally also have different day/year count bases.
It is possible to calculate a money market yield for a bond, exactly as we did
for a medium-term CD in Chapter 2. An alternative is to compromise
between the two approaches by using the bond approach for (1) above and
the CD approach for (2) and (3). The result is to adjust the basic bond dirty
price formula to the following:
Calculation
summary
Money market yield for a bond
P=
[
(
1–
100
R
×
i
(1 + n × W) n
(
1
(1
1–
+ ni
365
× 360
)
)
))
]
N
1
365
(1 + ni × 360
+
(1
+ ni
1
365 N–1
× 360
)
where i and W are the yield and fraction of a coupon period on a money
market basis rather than a bond basis.
Example 5.8
What is the money market yield for the same bond as used in Example 5.1, assuming that the appropriate money market convention is ACT/360?
We know that the dirty price is 111.4811. On an ACT/360 basis, the fraction of a
ye
coupon period from settlement to the next coupon is –
´yr¥π rather than ´–
¥π. We therefore have:
111.4811 =
100
64
(1 + i × 360
(1 – (
× 0.09 ×
)
(1 – (
(
1
1+i×
365
360
)+ 1
(1 + i ×
))
6
)
1
1 + i × 365
360
)
)
365 5
360
The solution to this is that the money market yield is 7.878%.
This cannot be solved by the HP bond calculator. The HP does have an equation solver however (available only in algebraic mode rather than RPN
102
5 · Bond Market Calculations
mode) which can be used to solve the formula as follows. Note that the equation solver respects the normal mathematical conventions for the order of
operations, whereas the HP used normally in algebraic mode does not (operating instead in the order in which operations are entered, thus requiring the
use of extra parentheses).
➞
SOLVE ■
PRICE = 100 × (CPN × (1 – 1 ÷ (1 + YLD × 365 ÷ 360) ■ ∧ N) ÷ (1 – 1÷ (1 + YLD
× 365 ÷ 360)) + 1 ÷ (1+ YLD × 365 ÷ 360) ■ ∧ (N – 1)) ÷ (1 + YLD × DAYS ÷ 360)
CALC
111.4811 PRICE
.09 CPN
6N
64 DAYS
YLD
Moosmüller yield
The Moosmüller method of yield calculation (Figure 5.1) is used in some
German markets. It is also used by the US Treasury (rather than the market)
for US bonds. It is similar to the money market yield in the previous section, in
that it calculates the final discounting for the next coupon date to settlement
using simple interest rather than compound interest. The day/year convention
however is not changed to a money market basis. The result is the following
formula, which can be seen to be a hybrid between the formulas for yield to
maturity and money market yield.
P=
(
(
[
1–
)
1
Calculation
summary
]
(1 + ni )N + 1
R×
100
(1 + ni × W) n 1 – 1
(1 + ni )N–1
(1 + ni )
)
Fig 5.2
Yield %
Comparison of yield to maturity with Moosmüller yield
for a 10% coupon bond priced at par
10.1
10.0
9.9
9.8
9.7
9.6
9.5
9.4
9.3
9.2
9.1
9.0
Yield to maturity
Moosmüller yield
1
2
3
4
5
Years to maturity
6
7
103
Part 2 · Interest Rate Instruments
Zero-coupon and strip prices
Pricing a zero-coupon bond or a single component of a stripped bond, is similar in concept to pricing a coupon-bearing bond except that the fraction of
an interest period used for discounting – generally taken as the time to the
next scheduled coupon date for a coupon-bearing bond – must be determined. It is appropriate to use the date which would be the next coupon date
if it existed – known as a “quasi-coupon date”. There remain then the same
choices as with coupon-bearing bonds: which day/year convention to use,
whether to use simple interest for short maturities, and whether to use a mixture of simple and compound interest for longer maturities. As there is no
coupon, the clean price and dirty price are the same.
Example 5.9
What is the price of the following zero-coupon bond?
Maturity date:
Settlement date:
Yield:
Price / yield calculation basis:
28 September 2005
15 January 1998
8.520%
ACT/ACT (semi-annual)
As the quasi-coupon periods are semi-annual, the next quasi-coupon date is 28
March 1998 and the previous one was 28 September 1997 (despite the fact that
these are Saturday and Sunday respectively). On an ACT/ACT basis therefore, the
fraction of a quasi-coupon period from settlement to the next quasi-coupon date is
&72
181. The price is therefore:
100
72
= 52.605014
+15
0.0852
1 + 2 181
(
)
This is exactly the same as the conventional general bond price formula given earlier, with R (coupon rate) = 0, n (coupon frequency) = 2 and ACT/ACT semi-annual
as the day/year convention.
.0852 ENTER 2 ÷ 1 +
72 ENTER 181 ÷ 15 + ■ ∧
100 ■ xy ÷
OR
FIN BOND TYPE A/A SEMI EXIT
15.011998 SETT
28.092005 MAT
0 CPN%
MORE 8.52 YLD%
PRICE
Because the quasi-coupon dates are used as reference points for discounting
to a present value but do not reflect actual cashflows, two identical zerocoupon bonds stripped from different coupon-bearing bonds could appear to
have inconsistent yields.
104
5 · Bond Market Calculations
Example 5.10
Suppose that the bond in Example 5.9 is in fact a coupon stripped from a UK gilt
(semi-annual coupons). Consider another zero-coupon bond in the same currency
with the same maturity date and face value, but which is in fact a coupon stripped
from a French government bond (annual coupons). What is the yield of this bond if
the price is the same as the bond in Example 5.9?
The fraction of a period to the next quasi-coupon date (28 September 1998) is now
wty
´–
¥†. The price is therefore given by:
100
52.605014 =
256 +7
(1 + yield) 365
Solving for the yield gives 8.699%.
Continuing from the previous example:
MORE TYPE ANN EXIT
MORE YLD%
OR
52.605014 ENTER 100 ÷
256 ENTER 365 ÷ 7 + ■ 1/x ■ ∧
■ 1/x 1 –
We would not expect the yields in Examples 5.9 and 5.10 to be the same,
because one is semi-annual and the other is annual. However, the usual conversion from semi-annual to annual will not bring them in line:
– 1 = 8.701%
(1 + 0.0852
2 )
2
In this case, the annual equivalent of the yield quoted for the gilt strip is
greater than the yield quoted for the identical French strip. The reason is the
uneven division of days between the semi-annual quasi-coupon periods (181
days, then 184 days etc.).
A SUMMARY OF THE VARIOUS APPROACHES TO PRICE / YIELD
The different conventions used in different markets to relate price and yield
are just that – different conventions. They should not affect the economics of
an instrument. If the market convention is to trade a particular instrument in
terms of yield rather than price, the investor must first convert this yield to a
price using the appropriate conventions. The economics of the investment are
then determined by what the price actually is and what the future cashflows
are. From these, to compare two investments, the investor can ignore the
yield quoted by the market and use a single consistent approach of his/her
choice to calculate yields for comparison. In the next chapter we see how, in
reverse, he/she can calculate a price for each investment using zero-coupon
yields; again, this can be done consistently, ignoring market conventions.
105
Part 2 · Interest Rate Instruments
Summarising the issues we have already seen, the following factors need to
be considered.
Day/year convention for accrued coupon
This is ACT/365 (for example, Norway), ACT/ACT (France), 30(E)/360
(Germany) or 30(A)/360 (US federal agency).
Day/year convention for discounting cashflows to the dirty price
This is often the same as for accrued coupon, but may not be (Italy). For a
consistent calculation disregarding market convention, ACT/365.25 might be
used to compensate on average for the distorting effect of leap years.
Adjustment for non-working days
Conventional bond calculations generally ignore the effect of non-working
days, assuming coupons are always paid on the regular scheduled date (even
if this is not a working day). This approach is not taken with medium-term
CDs. The UK Stock Exchange calculations for gilt prices for example however, have in the past discounted to the dirty price using actual payment
dates for the cashflows.
Simple interest v. compound interest
In some markets, the yield for a bond in its final coupon period is calculated
on the basis of simple interest (US). For bonds with more than one coupon
remaining, compound interest is usual, although it is possible for example to
take simple interest for the first fractional coupon period compounded with
periodic interest thereafter (the US Treasury’s calculation method for new
issues). For a medium-term CD, simple interest discount factors for each
period are compounded together.
Compounding method
It is usual to discount bond cashflows by compounding in “round” years.
Using the same notation as earlier in this chapter, the discount factor is
1 W + a number of whole coupon periods
i
. A more precise approach is to use the total
1+n
exact number of days to each cashflow rather than a round number of years:
( )
total days to cashflow
×n
a factor of 1 + i
. For medium-term CDs, the approach is
year
n
is to compound each exact time separately.
(
)
Other considerations
One basic question is whether a yield is quoted annually, semi-annually or
quarterly. The usual convention is to quote an annual yield if the coupons
are paid annually, a semi-annual yield if the coupons are paid semi-annually
etc. Care would need to be taken for example in comparing a semi-annual
106
5 · Bond Market Calculations
yield for a UK gilt paying semi-annual coupons with a quarterly yield for a
gilt paying quarterly coupons.
The concept of a bond yield as an internal rate of return implies that all
coupons are also reinvested at the yield. An alternative is to assume a particular reinvestment rate (or series of different reinvestment rates). The coupon
cashflows are then all reinvested at this rate until maturity. The yield is then
the zero-coupon yield implied by the total future value accumulated in this
manner, and the initial bond price.
DURATION, MODIFIED DURATION AND CONVEXITY
Duration
The maturity of a bond is not generally a good indication of the timing of the
cashflows arising from the bond, because a significant proportion of the
cashflows may occur before maturity in the form of coupon payments, and
also possibly partial redemption payments.
One could calculate an average of the times to each cashflow, weighted by
the size of the cashflows. Duration is very similar to such an average. Instead
of taking each cashflow as a weighting however, duration takes the present
value of each cashflow.
Example 5.11
Consider the same 7-year 10% coupon bond as in Example 5.5, with a price of
95.00 and a yield of 11.063%. The size and timing of the cashflows of the bond
can be shown as follows:
+10
1 year
+10
1 year
+10
1 year
+10
1 year
+10
1 year
+10
1 year
+110
1 year
The average time to the cashflows weighted by the cashflows themselves would
be calculated as:
∑ (cashflow × time to cashflow)
sum of the cashflows
=
(10 × 1) + (10 × 2) + (10 × 3) + (10 × 4) + (10 × 5) + (10 × 6) + (110 × 7)
years
10 + 10 + 10 + 10 + 10 + 10 + 110
=
980
years = 5.76 years
170
If you consider the diagram above as a beam with weights of 10,10, . . .110 placed on
it, the point 5.76 along the beam is the point at which the beam would be balanced.
Now consider the same averaging process but instead using the present value of each
cashflow (discounted at the yield of 11.063%). These present values are as follows:
107
Part 2 · Interest Rate Instruments
+9.00
1 year
+8.11
1 year
+7.30
1 year
+6.57
1 year
+5.92
1 year
+5.33
1 year
+52.77
1 year
The weighted average is now:
(9.00 × 1) + (8.11 × 2) + (7.30 × 3) + (6.57 × 4) + (5.92 × 5) + (5.33 × 6) + (52.77 × 7)
yrs
(9.00 + 8.11 + 7.30 + 6.57 + 5.92 + 5.33 + 52.78)
=
504.37
years = 5.31 years
95.00
The duration of the bond is thus 5.31 years.
Note that the lower half of the calculation (9.00 + 8.11 ... + 52.77) is simply the
price of the bond, because it is the NPV of the cashflows.
10 ENTER 1.11063 ÷
10 ENTER 1.11063 ENTER 2 ■ ∧ ÷ 2 × +
10 ENTER 1.11063 ENTER 3 ■ ∧ ÷ 3 × +
10 ENTER 1.11063 ENTER 4 ■ ∧ ÷ 4 × +
10 ENTER 1.11063 ENTER 5 ■ ∧ ÷ 5 × +
10 ENTER 1.11063 ENTER 6 ■ ∧ ÷ 6 × +
110 ENTER 1.11063 ENTER 7 ■ ∧ ÷ 7 × +
95 ÷
Calculation
summary
Duration =
∑ (present value of cashflow × time to cashflow)
∑ (present value of cashflow)
It is worth noting that for a zero-coupon bond, there is only one cashflow, at maturity. The duration of a zero-coupon bond is therefore the
same as its maturity.
The concept of duration can be extended to any series of cashflows, and
hence to a portfolio of investments.
Duration is useful partly because of its relationship with the price sensitivity of a bond (see modified duration below) and partly because of the
concept of investment “immunization.”
If I invest in a bond and there is a fall in yields (both short-term and longterm), there are two effects on my investment. First, I will not be able to earn
as much as I had expected on reinvesting the coupons I receive. As a result, if
I hold the bond to maturity, my total return will be less than anticipated. The
price of the bond will however rise immediately (yield down, price up). If I
hold the bond for only a very short time therefore, my total return will be
more than anticipated because I will not have time to be affected by lower
reinvestment rates. There must be some moment between now and the
bond’s maturity when these two effects – the capital gain from the higher
bond price and the loss on reinvestment – are in balance and the total return
is the same yield as originally anticipated. The same would be true if yields
rise – there is some point at which the capital loss due to the higher bond
price would be balanced by the reinvestment gains.
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5 · Bond Market Calculations
Suppose that an investor wishes to be sure of the total return on his/her
portfolio between now and a particular time in the future, regardless of interest rate movements. It can be shown that, if he/she arranges the portfolio to
have a duration equal to that period (rather than have a maturity equal to it),
he will then not be vulnerable to yield movements up or down during that
period – the portfolio will be “immunized”.
There are practical problems with this concept. First, the idea assumes that
short-term reinvestment rates and long-term bond yields move up or down
together. Second, the portfolio’s duration will change as its yield changes,
because the calculation of duration depends on the yield. In order to keep the
portfolio’s duration equal to the time remaining up to his/her particular
investment horizon, and so remain immunized, the investor therefore needs
to adjust the portfolio continually by changing the investments.
Modified duration
It is useful to know the sensitivity of a bond price to yield changes – that is, if
a yield rises by a certain amount, how much will the bond’s price fall? The
answer can be seen as depending on how steeply the price / yield curve slopes
(see Figure 5.3).
Price
Price / yield relationship for a 7-year 10% coupon bond
Fig 5.3
170
160
150
140
130
120
110
100
90
80
70
60
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Yield %
If the curve is very steeply sloped, then a given move up in the yield will
cause a sharp fall in the price from 95.00. If the curve is not steeply sloped,
the price fall will be small. This gives the following approximation:
change in price = change in yield × slope of curve
We are probably more interested in how much the value of our investment
changes relative to the size of the investment (rather than as an absolute
amount) – that is, change in price . This must therefore be equal to:
change in
dirty price
slope of curve
yield × dirty price
Mathematically, the slope of the curve is
dP
. By taking the general bond price
di
109
Part 2 · Interest Rate Instruments
formula:
Ck
P = ∑k
(
dk × n
year
)
1 + ni
and differentiating, we get:
dP
=–
di
∑
Ck
d
dk
n year
(1+ ni )
k
× year
(1 + ni )
Comparing this with the formula for duration in the previous section, it can
be seen that:
slope of curve
=
dirty price
dP
di
/
dirty price
=–
duration
(1 + ni )
change in price
Therefore it can be seen that the sensitivity factor relating dirty price to –(change
duration
in yield) is
. Because this factor is so similar to duration, it is known
(1 + ni )
as “modified duration.”
Calculation
summary
Modified duration =
– dP
di
dirty price
=
duration
(1 + ni )
So that we have:
Calculation
summary
Approximation
Change in price ≈ – dirty price × change in yield × modified duration
In some markets, modified duration is known as “volatility”.
Example 5.12
Consider the same bond as before, and assume a 1% rise in the yield from
11.063% to 12.063%.
5.31
= 4.78 years
(1 + 0.11063)
As the duration is 5.31 years and n = 1 (coupons are annual), the modified duration is:
Using the price sensitivity, we know:
Change in price ≈ – dirty price x change in yield × modified duration
= –95.00 × 0.01 × 4.78 = –4.54
110
5 · Bond Market Calculations
We should therefore expect the price to fall from 95.00 to 95.00 – 4.54 = 90.46.
If now we check this by repricing at 12.063% (for example, by using the HP’s TVM
function), we find that the bond’s price has actually fallen to 90.60.
Dollar value of an 01
A measure very closely related to modified duration is the “dollar value of an
01” (DV01) – or the “present value of an 01” (PV01), or “the value of a basis
point”. This is simply the change in price due to a 1 basis point change in yield
– usually expressed as a positive number. From the above, it can be seen that:
DV01 = modified duration × dirty price × 0.0001
Calculation
summary
Convexity
For small yield changes, the approximation above is fairly accurate. For
larger changes, it becomes less accurate. The reason that the modified
duration did not produce exactly the correct price change in the last example is that the slope of the curve changes as you move along the curve. The
equation:
change in price = change in yield × dP
di
in fact calculates the change along the straight line shown in Figure 5.4
rather than along the curve.
Price
Price / yield relationship for a 7-year 10% coupon bond
170
160
150
140
130
120
110
100
90
80
70
60
Fig 5.4
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Yield %
As a result, using modified duration to calculate the change in price due to
a particular change in yield will generally underestimate the price. When the
yield rises, the price does not actually fall as far as the straight line suggests;
when the yield falls, the price rises more than the straight line suggests. The
difference between the actual price and the estimate depends on how curved
111
Part 2 · Interest Rate Instruments
the curve is. This amount of curvature is known as “convexity” – the more
curved it is, the higher the convexity.
Mathematically, curvature is defined as:
Key Point
Convexity =
d2P
di2
dirty price
By applying this to the bond price formula, we get:
Calculation
summary
∑
Convexity =
[
Ck
(1
dk
i n year+2
+n
)
(
)
dk
dk 1
× year
× year
+n
]
dirty price
Using convexity, it is possible to make a better approximation of the change
in price due to a change in yield:
Calculation
summary
Better approximation
Change in price ≈ – dirty price × modified duration × change in yield
+ q-∑ dirty price × convexity × (change in yield)2
Example 5.13
Using the same details again as in the last example, the bond’s convexity can be
calculated as:
(
10
(1.11063)3
10
10
10
× 2 + (1.11063)
4 × 6 + (1.11063)5 × 12 + (1.11063)6 × 20
)/
10
10
110
+ (1.11063)
7 × 30 + (1.11063)8 × 42 + (1.11063)9 × 56
= 31.08
95.00
A 1% rise in the yield would then give the following approximate change in price:
–95 × 4.78 × .01 + 12 × 95 × 31.08 × (.01)2 = –4.39
We should therefore now expect the price to fall from 95.00 to 95.00 – 4.39 = 90.61
– which is very close to the actual price of 90.60.
For bonds without calls, it can be shown in general that:
• for a given yield and maturity, a higher coupon rate implies lower duration and convexity
• for a given coupon rate and maturity, a higher yield implies lower duration and convexity.
In Example 5.11 convexity is a positive number. This is always true for a
straightforward bond – that is, the shape of the price / yield curve is roughly
as shown in Figure 5.4. It is possible, however, for convexity to become negative at some point along the curve. Suppose, for example, that the bond
issuer has the choice of redeeming the bond early if market yields fall below a
112
5 · Bond Market Calculations
certain level. In that case, the price will cease rising beyond a certain point as
yields fall. The result is a reversal of the curvature at low yields. Mortgagebacked securities, where the home-owners are more likely to repay mortgages
and refinance as yields fall, can provide a similar situation.
In general, high positive convexity is good from an investor’s point of view.
If two bonds have equal price, yield and duration but different convexities, the
bond with higher convexity will perform relatively better if the yield changes.
In practice, therefore, the two bonds should not be priced the same. In the
same way, when hedging a portfolio, an investor should try to ensure higher
convexity in his/her long positions and lower convexity in short positions.
Portfolio duration
As mentioned above, the concept of duration – and also modified duration
and convexity – can be applied to any series of cashflows, and hence to a
whole portfolio of investments rather than to a single bond.
To calculate precisely a portfolio’s duration, modified duration or convexity, the same concept should be used as for a single bond, using all the
portfolio’s cashflows and the portfolio’s yield (calculated in the same way as
for a single bond). In practice, a good approximation is achieved by taking a
weighted average of the duration etc. of each investment:
Approximations for a portfolio
Duration =
∑ (duration of each investment × value of each investment)
value of portfolio
Modified duration =
Convexity =
Calculation
summary
∑ (mod. dur. of each investment × value of each investment)
value of portfolio
∑ (convexity of each investment × value of each investment)
value of portfolio
A portfolio’s modified duration, for example, gives the sensitivity of the
whole portfolio’s value to yield changes. Although this has the limitation that
it assumes all yields move up or down in parallel along the yield curve, it can
provide a useful quick measure of risk. With the same limitation, an organization wishing to avoid any such risk can match the modified durations of its
liabilities and its assets.
Example 5.14
We own the following portfolio:
Bond A
Bond B
Bond C
Face value
Dirty price
Modified duration
10 million
5 million
7 million
107.50
98.40
95.25
5.35
7.20
3.45
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Part 2 · Interest Rate Instruments
How much of the following bond should we short to make the portfolio immune to
small changes in yield, assuming parallel movements in the yield curve?
Dirty price
110.20
Bond D
Modified duration
9.75
For any small change in yield, the change in value of our portfolio is approximately:
– change in yield ×
98.40
95.25
× 5.35) + (5 mln ×
× 7.20) + (7 mln ×
× 3.45)]
[(10 mln ×107.50
100
100
100
We therefore need to short enough of bond D to have an offsetting effect. The
above change in value therefore needs to equal:
(
– change in yield × face value of bond D ×
110.20
× 9.75
100
)
Therefore face value of bond D to be sold =
(10 mln × 1.075 × 5.35) + (5 mln × 0.984 × 7.2) + (7 mln × 0.9525 × 3.45)
1.102 × 9.75
= 10.8 million
10 ENTER 1.075 × 5.35 ×
5 ENTER .984 × 7.2 × +
7 ENTER .9525 × 3.45 × +
1.102 ÷ 9.75 ÷
BOND FUTURES
A bond futures contract is generally an agreement whereby the seller must
deliver to the buyer an agreed amount of a bond at an agreed time, for an
agreed price. In practice, bond futures contracts are generally closed out before
maturity in the same way that short-term futures contracts are, and the profit /
loss is captured through variation margins. In the case of most bond futures
contracts however, a bond futures buyer can in theory insist on delivery of a
bond at maturity of the contract. There are several complications which do not
arise in the case of short-term interest rate futures.
Bond specification
A bond futures contract must be based on a precisely specified bond, in the
same way that a short-term interest rate futures contract is generally based
precisely on a 3-month deposit. It may be preferable, however, to allow any
one of a range of existing bonds – which can change over time – to be delivered at maturity of the futures contract. Bond futures prices are therefore
usually based on a notional bond index rather than any one of these particu114
5 · Bond Market Calculations
lar bonds. In the case of a US treasury bond futures, for example, the bond
specified is a fictional 8 percent bond of at least 15 years’ maturity.
Deliverable bonds and conversion factors
The seller of the futures contract cannot of course deliver this fictional bond.
Instead, he is usually entitled to deliver any one of a range of bonds which is
defined in the specifications for the futures contract. In this case, it is the
seller who chooses which bond to deliver to the buyer. In the case of US treasury bond futures, for example, the seller may deliver any bond maturing at
least 15 years after the first day of the delivery month if the bond is not
callable. If it is callable, the earliest call date must be at least 15 years after
the first day of the delivery month.
Because the different deliverable bonds have different coupons and maturities, they need to be put on a common basis. The futures exchange therefore
publishes a “price factor” or “conversion factor” for each deliverable bond.
The amount paid by the buyer if the bond is delivered then depends on this
conversion factor. In the case of a treasury bond, this is the price per $1
nominal value of the specific bond at which the bond has a gross redemption
yield of 8 percent on the first day of the delivery month (i.e. it has the same
yield as the coupon of the fictional bond underlying the contract). The maturity of the deliverable bond is found by measuring the time from the first day
of the delivery month to the maturity of the bond (first call day if callable)
and rounding down to the nearest quarter.
Conversion factor =
clean price at delivery for one unit of the deliverable bond, at which that
bond’s yield equals the futures contract notional coupon rate
Key Point
On the delivery day, the specific bond nominated by the seller will be delivered and the seller will receive from the buyer the relevant invoicing amount.
The invoicing amount is based on the “Exchange Delivery Settlement Price”
(EDSP – the futures price at the close of trading for that futures contract, as
determined by the exchange) and the size of the futures contract ($100,000
in the case of a US treasury bond futures):
Invoicing amount = face value ×
(
)
EDSP
× conversion factor + accrued coupon rate
100
This choice of deliverable bonds also gives rise to the concept of “cheapest to
deliver”: the seller will always choose to deliver whichever bond is the cheapest for him to do so – known as the “cheapest to deliver” or “CTD” bond.
115
Part 2 · Interest Rate Instruments
Key Point
A bond futures contract is based on a notional bond. The real
bonds deliverable into the contract are made comparable by their
conversion factors
Delivery date
Delivery specifications vary between futures contracts and exchanges. In the
case of a US treasury bond futures, for example, the seller is entitled to
deliver on any business day in the delivery month. Clearly he will deliver
later if the coupon he is accruing is higher than the cost of funding the position and earlier if the coupon is lower.
Coupons
If there is an intervening coupon payment on the actual bond which the
futures seller expects to deliver, he will take this into account in calculating
the futures price.
Pricing
The theoretical futures price depends on the elimination of arbitrage. The
seller of a futures contract, if he delivers a bond at maturity of the futures
contract, will receive the invoicing amount on delivery. He will also receive
any intervening coupon plus interest earned on this coupon between receipt
of the coupon and delivery of the bond to the futures buyer.
In order to hedge themselves, the futures sellers must buy the bond in the
cash market at the same time as they sell the futures contract. For this they
must pay the current bond price plus accrued coupon. This total amount
must be funded from the time they buy the bond until the time they deliver it
to the futures buyer.
By delivery, the market futures price (which becomes the EDSP at the close
of the contract) should converge to the cash market price of the CTD bond
divided by the conversion factor. If this were not so, there would be an arbitrage difference between the invoicing amount for the CTD at delivery and
the cost of buying the CTD bond in the cash market at the same time. During
the period from selling the futures contract to delivery, the futures seller pays
or receives variation margin (as with short-term interest rate futures) based
on the notional amount of the futures contract. These variation margin cashflows represent the difference between the price at which he sold the futures
contract and the EDSP.
It can be seen from the cashflows shown below that, in order to achieve a
hedge which balances correctly, the nominal amount of cash bond sold
size of futures contract
should be notionalconversion
. If the buyer requires delivery of the bond,
factor
the seller will need to buy or sell a small amount of the cash bond at maturity
– the difference between the notional futures amount, which must be delivered, and the amount already bought as the hedge. This will be done at the
116
5 · Bond Market Calculations
price of the cash bond at maturity, which should converge to (EDSP × conversion factor), as noted above.
Assuming that the futures seller makes zero profit / loss, the cashflows
received and paid by the futures seller should net to zero. For any given
notional face value of futures, these cashflows are as follows:
Receive on delivery of the bond
face value ×
(
)
EDSP
× conversion factor + accrued coupon rate at delivery
100
Receive as variation margin
face value ×
(
)
futures price – EDSP
100
Receive any intervening coupon
face value
× (coupon rate + reinvestment)
conversion factor
Pay the total cost of funding the cash bond purchase
(
)
face value
cash bond price
+ accrued coupon rate at start ×
×
conversion factor
100
(
1 + funding rate ×
days to delivery
year
)
Pay (or receive) the cost of the difference between the amount of bond
hedged, and the amount of the bond to be delivered to the buyer
(
face value –
)(
)
face value
EDSP × conversion factor accrued coupon
+
×
rate at delivery
conversion factor
100
From this, it follows that:
Calculation
summary
Theoretical bond futures price =
([bond price + accrued coupon now] × [1 + i × ]) –
days
year
(accrued coupon at delivery) – (intervening coupon reinvested)
conversion factor
where i = short-term funding rate
Example 5.15
What is the theoretical September T-bond futures price on 18 June if the cheapest_9 )? The
to-deliver bond is the Treasury 12 –34 % 2020, trading at 142–09 (i.e. 14232
conversion factor for the 2020 is 1.4546. Coupon dates are 15 May and 15
November. Short-term funds can be borrowed at 6.45%.
117
Part 2 · Interest Rate Instruments
Answer:
Payment for the bond purchased by the futures seller to hedge himself is made on
Accrued coupon now = 12.75 ×
35
= 1.212636
368
19 June. Coupon on the purchase of the bond is accrued for 35 days. The current
coupon period is 184 days. Therefore:
Assume that delivery of the bond to the futures buyer requires payment to the
futures seller on 30 September. The futures seller must then fund his position from
19 June to 30 September (103 actual days) and coupon on the sale of the bond
will then be accrued for 138 days.
Therefore:
Accrued coupon at delivery = 12.75 ×
Theoretical futures price =
138
= 4.781250
368
– 4.781250
(142.281250 × 1.212636) × (1 + 0.0645 × 103
360 )
1.4546
= 97.1818
/
= 97–06 (i.e. 97 6
32
)
12.75 ENTER 35 × 368 ÷
142.28125 +
.0645 ENTER 103 × 360 ÷ 1 + ×
12.75 ENTER 138 × 368 ÷
–
1.4546 ÷
(Accrued interest at start)
(Clean bond price at start)
(Accrued interest at end)
(Theoretical futures price)
The construction above of a theoretical futures price does not take account of
the fact that the seller of a bond futures contract has a choice of which bond to
deliver. This effectively gives the seller an option built into the futures contract.
This optionality has a value, which should in general be reflected in a slightly
lower theoretical futures price than the formula above suggests.
Forward bond prices
The arbitrage method used above to calculate a theoretical bond futures price
could equally well be used to calculate a forward market price for a bond
which is to be delivered on any date later than the normal convention – that is,
a forward bond price. In this case, there is no conversion factor involved.
Calculation
summary
Forward bond price =
([bond price + accrued coupon now] × [1 + i × ])
days
year
– (accrued coupon at delivery) – (intervening coupon reinvested)
Ignoring differences between the day/year conventions for the bond and
the short-term financing, the formula above can be rewritten as:
118
5 · Bond Market Calculations
(forward price – cash price) =
(
cash price × i –
coupon rate
/
cash price
[
100
+ accrued coupon now × i ×
) × days toyeardelivery
]
days
– interest earned on intervening coupon
year
The expression in square brackets is rather small, so that in general, the amount
(forward price – cash price) is positive or negative – that is, the forward price is
coupon rate
at a premium or a discount to the cash price – if i –
is positive or
(
)
/
negative. This is reasonable, because it reflects whether the cost of funding a
cash price
100
long bond position is greater or less than the coupon accruing on the position.
Key Point
Generally, a forward bond price is at a premium (discount)
to the cash price if the short-term funding cost is
coupon rate
greater than (less than)
.
cash price
100
Using futures to hedge a cash position
If a dealer takes a cash position in bonds, he can use bond futures to hedge
his position in the same way that a cash position in short-term interest rates
can be hedged by interest rate futures. The commodity traded in a bond
futures contract – the notional bond – will however behave differently from
any particular cash bond. As a result, the notional amount of the futures
hedge needs to be different from the face value of the cash position.
Suppose that a dealer takes a position in the CTD bond. We know that the
theoretical futures price is given by:
futures price =
([bond price + accrued coupon now] × [1 + i × ])
days
year
– (accrued coupon at delivery) – (intervening coupon reinvested)
conversion factor
If the price of the CTD changes therefore, the instantaneous change in the
futures price is found by differentiating the above formula:
change in futures price =
(
change in CTD price × 1 + i × days
year
conversion factor
or, change in CTD price = change in futures price ×
(
)
conversion factor
1 + i × days
year
)
119
Part 2 · Interest Rate Instruments
In order to hedge a position in $100 face value of the CTD bond therefore,
conversion factor
the dealer should take an opposite position in $100 ×
nomi1+ i × days
year
(
)
nal of the futures contract. This will still leave the risks that the actual
futures price will not move exactly in line with the CTD bond, and that the
CTD bond will change, but it will provide an approximate hedge.
The factor
(
conversion factor
1+ i × days
year
)
is known as a hedge ratio – the necessary ratio
of the size of the futures hedge to the size of the underlying position.
We could reverse this concept to say that a dealer could hedge a futures
position by an opposite position in the CTD bond. The amount of the CTD
bond required is then:
notional amount of futures contract ×
(1+ i × days
year)
conversion factor
Note that this is not exactly the same as the amount of CTD bond we used in
establishing the theoretical futures price in the previous section: the amount
of futures contract
there was simply notional amount
.
conversion factor
The difference arises because in establishing the theoretical futures price,
we needed an arbitrage which we could hold to delivery – even though, in
practice, futures contracts are rarely delivered. In this section, on the other
hand, we are concerned about a hedge for an instantaneous change in price.
If we held the hedge to delivery, the (1 + i × days
factor would converge to 1.
year)
Example 5.16
A dealer wishes to hedge his short position in $15 million face value of the bond
which is currently the CTD for the US treasury bond futures contract. The conversion
factor for the CTD is 1.1482. Assume that delivery of the futures contract is in 73
days and that the cost of short-term funding is 5.2%. The size of a US treasury bond
futures contract is $100,000 nominal. How should the dealer hedge his position?
Hedge ratio =
(
conversion factor
1 + i × days
year
)(
=
1.1482
1 + 0.052 ×
73
360
)
= 1.1362
The dealer should therefore buy $15 million x 1.1362 = $17,043,000 nominal of
futures. As the nominal size of each futures contract is $100,000, this involves
17,043,000
buying
= 170 futures contracts.
100,000
120
5 · Bond Market Calculations
If the dealer wishes to hedge a different bond, he will need to assess how that
bond’s price is likely to move compared with the CTD’s price. For small yield
changes, one approach is to use modified duration. Assuming that the yield on
the actual bond purchased and the yield on the CTD move in parallel, we have:
change in bond price =
– dirty bond price × modified duration of bond × yield change
and:
change in price of CTD =
– dirty price of CTD × modified duration of CTD × yield change
so that:
change in bond price =
change in price of CTD ×
dirty bond price
dirty price of CTD
×
modified duration of bond
modified duration of CTD
This gives a hedge ratio as follows:
notional amount of futures contract required to hedge a positon in bond A
=
face value of bond A
Calculation
summary
dirty price of bond A
modified duration of bond A
×
dirty price of CTD bond modified duration of CTD bond
×
conversion factor for CTD bond
(1 + i × )
days
year
where i = short-term funding rate
Note that this hedge assumes, as with all modified duration hedging, that the
yield curve shift is the same for all bonds – that is, that the yields on bond A and
the CTD bond respond in the same way to market changes. It might be that even
for a yield curve shift which is parallel in general, bond A in particular responds
more sluggishly or less sluggishly than the market in general. Any expectation of
this would need to be taken into account in the size of the hedge.
CASH-AND-CARRY ARBITRAGE
Overview of repos
“Repo” is short for “sale and repurchase agreement” and is essentially a
transaction whereby the two parties involved agree to do two deals as a
package. The first deal is a purchase or sale of a security – often a government bond – for delivery straight away (the exact settlement date will vary
according to the market convention for the security involved). The second
deal is a reversal of the first deal, for settlement on some future date.
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Part 2 · Interest Rate Instruments
Key Point
A repo is a purchase or sale of a security now,
together with an opposite transaction later
Because it is understood from the outset that the first deal will be reversed, it
is clear that both parties intend the transfer of securities (in one direction)
and the transfer of cash (in the other direction) to be temporary rather than
permanent. The transaction is therefore exactly equivalent to a loan of securities in one direction and a loan of cash in the other. The repo is structured
so that the economic benefit of owning the securities – income and capital
gains / losses – remains with their original owner. These are in fact the driving forces behind the repo market; all repos are driven by either the need to
lend or borrow cash, which is collateralized by securities – or the need to
borrow specific securities. The prices for both the original sale and subsequent repurchase are agreed at the outset. The difference between the two
prices is calculated to be equivalent to the cost of borrowing secured money.
Key Point
All repos are driven by either the need to borrow cash,
or the need to borrow a specific security
A repo is defined as an initial sale of securities followed by a subsequent
repurchase. A “reverse repo” is the opposite – an initial purchase of securities followed by a subsequent resale. Because the two parties involved are of
course doing opposite transactions, a “repo” to one party is a “reverse” to
the other. For this purpose, the deal is generally considered from the repo
dealer’s point of view. If he is effectively borrowing cash, the deal is a repo; if
he is effectively lending cash, the deal is a reverse. In a repo, the “seller” (or
Fig 5.5
A repo
Flows on the start date
Bond
Investor
Repo dealer
Cash
On maturity of the repo, the dealer will repay the cash with interest:
Flows on the end date
Same nominal amount of bond
Investor
Repo dealer
Same amount of cash plus interest
122
5 · Bond Market Calculations
“lender”) is the party selling securities at the outset and repurchasing them
later. The “buyer” (or “borrower” or “investor”) is the other party. (See
Figure 5.5.) It is important to note that the terminology is taken from the
viewpoint of the bond market, not the money market: the party borrowing
cash is usually known as the lender in the repo.
Price calculation
The total price at which the first leg of the repo is transacted is the straightforward current market price for the security, plus accrued coupon, taking into
account any margin (see below) if agreed. The total price for the second leg,
however, reflects only the repo interest rate and not the accrued coupon due on
the security at that time. This is because the security is in reality only playing
the part of collateral. The repo interest rate is calculated according to the
normal convention in the relevant money market. On a DEM repo, for example, this would be calculated on an ACT/360 basis; this is unaffected by the
fact that the coupon on the collateral might be calculated on a 30(E)/360 basis.
The price on the first leg of a classic repo is the market price.
The price on the second leg is the first price plus the repo interest.
Key Point
Example 5.17
Currency:
Deal date:
Settlement date:
Term:
Repo rate:
Collateral:
Clean bond price:
DEM
15 July 1996
17 July 1996
28 days (14 August 1996)
4.0% (ACT/360 basis)
DEM 60,000,000 nominal 8.5% bond with maturity 26 March
2004 and annual coupons (30(E)/360 basis)
108.95
Clean price of bond for value 17 July 1996 is 108.95
Accrued coupon on bond on 17 July 1996 =
111
× 8.5 = 2.6208333
360
Total purchase price = 111.57083333
Purchase amount = DEM 60,000,000 × 111.57083333 100 = DEM 66,942,500.00
Flows on 17 July 1996
DEM 60,000,000 bond
Buyer
Seller
DEM 66,942,500.00 cash
123
Part 2 · Interest Rate Instruments
On maturity of the repo, the seller will repay the cash with interest calculated at 4.0%:
Principal = DEM 66,942,500.00
Interest = DEM 66,942,500.00 × 0.04 ×
28
= DEM 208,265.56
360
Total repayment = DEM 67,150,765.56
Flows on 14 August 1996
DEM 60,000,000 bond
Buyer
Seller
DEM 67,150,765.56 cash
We can summarize these calculations as follows:
Calculation
summary
The cashflows in a classic repo
Cash paid at the beginning =
nominal bond amount × (clean price + accrued coupon)
100
Cash repaid at the end =
(
cash consideration at the beginning × 1 + repo rate ×
repo days
repo year
)
Implied repo rate
When we constructed a theoretical bond futures price earlier, we did so by
considering how the seller of a bond futures contract could hedge himself.
This was by borrowing cash, using the cash to buy the bond and holding the
bond until the futures contract matures and the bond is delivered against it.
If the actual futures price is the same as the theoretical price, this “round
trip” should give a zero result – no profit and no loss.
The same calculation can be considered in reverse: assuming that we already
know the current futures price and the current bond price, what is the interest
rate at which it is necessary to borrow the cash to ensure a zero result?
This interest rate is called the “implied repo rate” and is the break-even
rate at which the futures sale can be hedged. The reason for the name
“implied repo rate” is that in order to borrow the money to buy the bond,
the dealer can repo the bond out. It is thus the “repo borrowing rate implied
by the current futures price.” The “cheapest to deliver” bond will generally
be the one with the highest implied repo rate (because any other deliverable
bond will require a lower repo rate to break even).
Taking our earlier formula and reversing it, we get:
124
5 · Bond Market Calculations
Calculation
summary
Implied repo rate =
[
(futures price × conversion factor) + (accrued coupon at delivery of futures) +
(intervening coupon reinvested)
(bond price + accrued coupon now)
]
–1 ×
year
days
This can also be expressed as:
[
]
total cash received at delivery
year
–1 ×
initial cash expenditure
days
Cheapest-to-deliver bond
The CTD bond will change according to coupon and yield. If the futures
seller does hedge his position using one particular deliverable bond, his profit
on delivery at maturity will be:
nominal value of futures contract ×
dirty bond price
conversion factor
× (implied repo rate – actual repo rate) ×
days to delivery
year
The CTD bond will be the one which maximizes this profit. As yields fall,
bonds with lower duration are likely to become cheaper to deliver (because
the price of a bond with a low duration rises less, as yields fall, than the price
of a bond with a high duration) and vice versa.
The arbitrage structure
If in fact the current futures price, bond price and actual repo rate are not all
in line, an arbitrage opportunity will be available. Thus, if the actual repo
rate is less than the implied repo rate, it will be possible to finance the hedge
cheaply – that is, to buy the bond, repo it, sell the futures contract and
deliver the bond at maturity of the futures contract, all at a locked-in profit.
Such a round-trip is called “cash-and-carry arbitrage.”
If the actual repo rate is higher than the implied repo rate, it is possible to
effect a cash-and-carry arbitrage in reverse – that is, borrow a bond through
a reverse repo, sell the bond, buy the futures contract and take delivery of a
bond at maturity of the futures contract. A problem arises, however, that the
buyer of the futures contract has no control over which bond will be delivered. If the “cheapest to deliver” bond at maturity is not the same as the
bond he has borrowed, arbitrage will not be complete; he must then sell the
bond which has been delivered and buy the bond he has borrowed. In addition to the difference in value of the two bonds, this will also involve extra
transaction costs. Where the seller may choose the exact delivery date within
the month (as in US treasury bond and UK gilt futures), there is a further
uncertainty for the futures buyer.
125
Part 2 · Interest Rate Instruments
Example 5.18
CTD Bund 8 7/8% 22/02/2005 price:
Accrued coupon:
Bund futures price:
Conversion factor for CTD:
Repo rate:
Days to futures delivery date:
Futures contract amount:
Accrued coupon on CTD at futures delivery date:
105.24
1.922917
93.75
1.1181
3.29%
31
DEM 250,000
2.6625
Depending on whether the implied repo rate (= the break-even funding rate implied
by the current bond futures price and the current cash price of the “cheapest to
deliver” bond) is higher or lower than the actual current repo rate, the cash-andcarry arbitrage is:
Either (A)
•
•
•
•
Buy the cash CTD bond now.
Fund this purchase by repoing the bond.
Sell the bond futures contract.
Deliver the bond at maturity of the futures contract.
or (B) the opposite:
•
•
•
•
Sell the cash CTD bond now.
Borrow this bond (to deliver it now) through a reverse repo, using the cash
raised by the bond sale.
Buy the futures contract.
Take delivery of the futures contract at maturity and use the bond to deliver on
the second leg of the reverse repo.
(In practice, rather than deliver or take delivery of the bond at maturity of the
futures contract, the cash bond purchase or sale and the futures contract can both
be reversed at maturity. In (B) particularly, there would be no certainty that the
bond delivered to us by the futures seller would match the bond we are obliged to
return under the reverse repo.)
Assume for the moment that the profitable arbitrage is (A). (If in fact the result is
negative, the profitable arbitrage is (B) instead):
Sell the bond futures contract (notional DEM 250,000)
Buy the cash CTD bond with nominal amount
DEM 250,000
1.1181
= DEM 223,594
Cost of buying bond is nominal × (clean price + accrued coupon)
= DEM 223,594 × (105.24 + 1.922917)
= DEM 239,609.85
100
Total borrowing (principal + interest) to be repaid at the end
(
= DEM 239,609.85 × 1 + 0.0329 ×
126
31
= DEM 240,288.68
360
)
Anticipated receipt from delivering bond = notional amount of bond × (futures price
× conversion factor + accrued coupon)
100
5 · Bond Market Calculations
= DEM 223,594 × (93.75 ×1.1181 + 2.6625)
= DEM 240,328.61
100
In fact, the futures contract requires that DEM 250,000 nominal of the bond be
delivered by the seller, rather than the DEM 223,594 which has been purchased as
the hedge. The balance of DEM 26,406 would need to be purchased at the time of
delivery for onward delivery to the counterparty. Apart from transaction costs, this
should involve no significant profit or loss, as the futures exchange delivery settlement price should converge by delivery to (CTD cash price x conversion factor).
Profit = DEM (240,328.61 – 240,288.68) = DEM 39.93
Therefore profit per futures contract = DEM 39.93
In practice, the profit in Example 5.16 cannot be calculated precisely for several reasons:
• The CTD bond may not be the same at maturity of the futures contract as
•
•
it is when the arbitrage is established. This provides an advantage to the
futures seller, who can profit by switching his hedge from the original
CTD bond to a new one during the life of the arbitrage.
The futures price and the CTD bond cash price may not converge
exactly by maturity of the futures contract (that is, the basis may not
move exactly to zero).
The profit or loss on the futures contract is realized through variation
margin payments; because the timing of these payments is unknown in
advance, it is impossible to calculate their exact value.
Calculation
summary
Cash-and-carry arbitrage
Assume the arbitrage is achieved by buying the cash bond and selling the
futures:
Cash cost at start = nominal bond amount × (cash bond price + accrued
coupon at start)
100
(
Total payments = (cash cost at start) × 1 + repo rate ×
days to futures delivery
year
)
Total receipts = nominal bond amount × (futures price × conversion factor
+ accrued coupon at delivery of futures)
100
Profit = total receipts – total payments
For each futures contract sold, the nominal bond amount above is:
notional size of contract
converson factor
Basis, net cost of carry, and net basis
The concept of “basis” is similar to that for a short-term interest rate
futures contract, but using the conversion factor to adjust for the difference
127
Part 2 · Interest Rate Instruments
between the actual bond and the notional futures bond. Therefore for any
deliverable bond:
Calculation
summary
basis = bond price – futures price × conversion factor
Using the formula we derived earlier for the implied repo rate, this can also
be expressed as:
basis = coupon ×
days to delivery
year
– dirty bond price × implied repo rate ×
days to delivery
year
where “days to delivery” and “year” are calculated by the appropriate
method in each case.
Buying a bond and selling a futures contract is known as “buying the
basis”. Selling a bond and buying a futures contract is “selling the basis”.
The “net cost of carry” in holding any position is the difference between
the financing cost of holding it and the interest income from the position. If
we define this as negative when there is a net cost and positive when there is
a net income, we have:
Calculation
summary
net cost of carry = coupon income – financing cost
In the case of 100 units of a bond purchased to hedge a futures sale, this can
be expressed as:
days to delivery
year
days to delivery
– dirty bond price × actual repo rate ×
year
net cost of carry = coupon ×
The concept of “net basis” is similar to value basis for a short-term interest
rate futures contract and is defined as the difference between basis and cost
of carry:
Calculation
summary
net basis = basis – net cost of carry
From the above, it can be seen that:
net basis = dirty bond price × (actual repo rate – implied repo rate)
×
days to delivery .
year
If the actual repo rate is equal to the implied repo rate, the basis and net cost
of carry are equal and the net basis is zero. The net basis shows whether
there is potentially a profit in a cash-and-carry arbitrage (net basis is negative) or a reverse cash-and-carry arbitrage (net basis is positive).
128
5 · Bond Market Calculations
“Basis risk” in general is the risk that the prices of any two instruments
will not move exactly in line. If a long position in bond A is being hedged by
a short position in bond B for example, there is a risk that any loss on the
long position will not be fully offset by a gain on the short position.
Similarly, there is a basis risk involved in hedging a bond position by an offsetting futures position because the two positions again may not move
exactly in line. This point arose earlier in “Using futures to hedge a cash
position” and also in the chapter on Interest Rate Futures.
129
Part 2 · Interest Rate Instruments
EXERCISES
41. What is the yield of a 15-year bond paying an annual coupon of 7.5% and
priced at 102.45?
42. You buy the following bond for settlement on a coupon-payment date. What is
the cost of the bond? Make the calculation without using the built-in bond
function or time value of money function on a calculator.
Amount:
Remaining maturity:
Coupon:
Yield:
FRF 100,000,000.00
3 years
8.0%
7.0%
What are the current yield and simple yield to maturity of the bond? What is
the duration of the bond?
43. What is the clean price and accrued coupon of the following bond? Show the
structure of a formula you would use to calculate the clean price as an NPV
from first principles, but then use a calculator bond function for the answer.
Nominal amount:
Coupon:
Maturity date:
Settlement date:
Yield:
Price / yield calculation basis:
Accrued interest calculation basis:
5 million
6.8% (semi-annual)
28 March 2005
14 November 1997
7.4% (semi-annual)
ACT/ACT (semi-annual)
30/360
44. What is the yield of the following bond?
Coupon:
Maturity date:
Settlement date:
Price:
Price / yield calculation basis:
Accrued interest calculation basis:
8.3% (annual)
13 June 2003
20 October 1997
102.48
30/360 (annual)
ACT/365
45. What is the yield of the following zero-coupon bond? Try calculating this first
without using the HP bond functions.
Maturity date:
Settlement date:
Price:
Price / yield calculation basis:
27 March 2006
20 July 1998
65.48
ACT/ACT (semi-annual)
46 . You buy a US treasury bill at a discount rate of 8% with 97 days left to maturity. What is the bond-equivalent yield?
130
5 · Bond Market Calculations
47. What would the bond-equivalent yield be in the previous question if the T-bill
had 205 days left to maturity?
48. If the bond-equivalent yield which you want to achieve in the previous question
is 9%, at what discount rate must you buy?
49 . What is the price of the following bond?
Coupon:
Issue date:
Maturity date:
Settlement date:
Yield:
Price / yield calculation basis:
Accrued interest calculation basis:
4.5% in the first year of issue,
increasing by 0.25% each year to
5.75% in the final year. All coupons
paid annually.
3 March 1997
3 March 2003
11 November 1997
5.24%
30/360 (annual)
30/360
50. What is the yield of the following bond?
Coupon:
Maturity date:
Settlement date:
Redemption amount:
Price:
Price / yield calculation basis:
Accrued interest calculation basis:
3.3% (annual)
20 September 2007
8 December 1997
110 per 100 face value
98.00 per 100 face value
30/360 (annual)
30/360
You buy the above bond on 8 December 1997 and then sell it on 15 December
at 98.50. What is your simple rate of return over the week on an ACT/360
basis? What is your effective rate of return (ACT/365)?
51. What was the accrued coupon on 28 July 1997 on the following bonds?
a.
b.
c.
d.
e.
f.
g.
h.
7.5% gilt (ACT/365)
5.625% US treasury bond
6.25% Bund
7.25% OAT
3.00% JGB
7.00% OLO
8.80% Bono
9.50% BTP
Maturity 7 December 2005
Maturity 15 August 2005
Maturity 26 October 2005
Maturity 25 October 2005
Maturity 20 September 2005
Maturity 15 November 2005
Maturity 28 October 2005
Maturity 1 August 2005
52. Would the following bond futures contract trade at a discount or a premium to 100?
Date:
Futures maturity:
CTD bond:
CTD conversion factor:
9-month money market interest rate:
27 March 1998
December 1998
clean price 100
coupon 7% annual
1.0000
5% p.a.
131
Part 2 · Interest Rate Instruments
53. What is the theoretical September Bund futures price on 23 April if the cheapest-to-deliver bond is the 7.375% Bund of 2005, trading at 106.13? The
conversion factor for that bond is 1.1247. The last coupon date was 3 January.
Short-term funds can be borrowed at 3.35%. Futures delivery would be on 10
September. Assume that spot settlement for a Bund traded on 23 April would
be 25 April and the coupon is accrued on a 30/360 basis.
54. With the same details as in the previous question but supposing that the actual
futures price is 93.10, what is the implied repo rate?
55. Given the following information, there is a cash-and-carry arbitrage opportunity.
What trades are necessary to exploit it and how much profit can be made?
CTD Bund 8 7/8% 20/12/2000 price:
Accrued coupon:
Bund futures price:
Conversion factor for CTD:
Repo rate:
Days to futures delivery date:
Futures contract amount:
Accrued coupon on CTD
at futures delivery date:
102.71
3.599 per 100
85.31
1.2030
6.80%
24
DEM 250,000
4.191 per 100
56. You own the following portfolio on 14 August 1998:
Bond A
Bond B
Bond C
Face value Price
Coupon
Maturity
10 million
88.50 5.0% (annual)
8/7/2003
5 million 111.00 12.0% (annual) 20/3/2001
15 million
94.70 6.0% (annual) 14/10/2002
Duration
4.41 years
2.31 years
3.61 years
What is the approximate modified duration of the portfolio? How do you
expect the value of the portfolio to change if yields all rise by 10 basis points?
Assume that all the bond calculations are on a 30/360 basis.
57.
Bond A
Bond B
Price
88.50
107.50
Coupon
5.0% (annual)
10.0% (annual)
Maturity
8/7/2003
8/4/2010
Duration
4.41 years
7.56 years
You own 10 million face value of bond A. You wish to hedge this position by
selling bond futures. Bond B is currently the CTD for the futures contract and
has a conversion factor of 1.2754. The notional size of the futures contract is
100,000. Short-term interest rates are 10%. Settlement date is 14 August 1998
and the futures contract delivery date is 15 September 1998. How many
futures contracts should you sell? Assume that all the bond calculations are on
a 30/360 basis.
132
■
■
■
“A zero-coupon yield is
unambiguous: it is simply a
measure of the relationship
between a single future value and
its present value.”
134
6
Zero-coupon Rates and
Yield Curves
Zero-coupon yields and par yields
Forward-forward yields
Summary
Longer-dated FRAs
Exercises
135
Part 2 · Interest Rate Instruments
ZERO-COUPON YIELDS AND PAR YIELDS
Constructing par yields from zero-coupon yields
A zero-coupon instrument is one which pays no coupon. For example, a
company might issue a 5-year bond with a face value of 100 but no coupon.
Clearly investors would not pay 100 for this; they would pay considerably
less to allow for the fact that alternative investments would earn them interest. A zero-coupon yield is the yield earned on such an instrument, taking
into account the fact that it is purchased for less than its face value. It is the
(annual) interest rate which it is necessary to use to discount the future value
of the instrument (i.e. its face value) to the price paid for it now. This interest
rate is always given as the decompounded rate, not the simple annual rate
(i.e. in this example, it is not sufficient just to divide the difference between
face value and purchase price by 5).
In many markets and periods, there may be no zero-coupon instrument
available. There must nevertheless be a theoretical zero-coupon rate which is
consistent with the “usual” interest rates available in the market – that is, the
yields on coupon-bearing instruments. A clear advantage of zero-coupon
yields over these “usual” yields to maturity is that they avoid the question of
reinvestment risk.
A par yield is the yield to maturity of a coupon-bearing bond priced at
par. The reason for considering par yields in particular rather than couponbearing bond yields in general is that anything else would be arbitrary. We
could, for example, consider a range of existing five-year bonds – one with a
3 percent coupon, one with a 7 percent coupon and one with a 12 percent
coupon. Even assuming the same issuer for all the bonds and no tax or other
“hidden” effects, we would not expect the market yield to be exactly the
same for the three bonds. The cashflows are on average rather further in the
future in the case of the 3 percent coupon bond, than in the case of the 12
percent coupon bond; if longer term yields are higher than shorter term
yields, for example, the later cashflows should be worth relatively more than
the early cashflows, so that the 3 percent coupon bond should have a slightly
higher yield than the 12 percent coupon bond. The 7 percent coupon bond’s
yield should lie between the other two. Rather than choose one of these (or
even a different one) arbitrarily, we choose a bond priced at par to be “representative” of coupon-bearing yields for that particular maturity. On a
coupon date, this is a bond whose coupon is the same as the yield.
Clearly, however, it is very unlikely at any one time that there will be a bond
priced exactly at par for any particular maturity. Therefore we probably need
to use actual non-par, coupon-bearing bond yields available in the market to
construct the equivalent zero-coupon yields. From there, we can go on to construct what the par yields would be if there were any par bonds. It should be
noted of course that there is not only one par yield curve or one zero-coupon
yield curve. Rather, there are as many par yield curves as there are issuers.
Government bond yields will generally be lower than corporate bond yields or
interest rate swap yields, for example. Associated with each par yield curve is a
separate zero-coupon yield curve – also known as a spot yield curve.
136
6 · Zero-coupon Rates and Yield Curves
It is probably clearest to begin constructing these relationships from the
zero-coupon yield curve. A zero-coupon yield or spot yield is unambiguous:
it is simply a measure of the relationship between a single future value and its
present value. If we then know the market’s view of what zero-coupon yields
are for all periods, we can calculate precisely the NPV of a series of bond
cashflows by discounting each cashflow at the zero-coupon rate for that particular period. The result will be the price for that bond exactly consistent
with the zero-coupon curve. A single yield – the internal rate of return – can
then be calculated which would arrive at this same price; this single yield is
the usual “yield to maturity” quoted for the bond. If we can then construct a
bond where the NPV calculated in this way using the zero coupon rates is
100, the coupon of this bond is the par yield.
Example 6.1
Suppose that we have the following zero-coupon yield structure:
1-year:
2-year:
3-year:
4-year:
10.000%
10.526%
11.076%
11.655%
What are the zero-coupon discount factors? What would be the prices and yields
to maturity of:
a. a 4-year, 5% coupon bond?
b. a 4-year, 11.5% coupon bond?
c. a 4-year, 13% coupon bond?
The zero-coupon discount factors are:
1-year:
1
(1.1)
= 0.90909
2-year:
1
(1.10526)2
= 0.81860
3-year:
1
(1.11076)3
= 0.72969
4-year:
1
(1.11655)4
= 0.64341
(a) Price = (5 x 0.90909) + (5 x 0.81860) + (5 x 0.72969) + (105 x 0.64341)
= 79.84
Yield to maturity = 11.58% (using TVM function of HP calculator)
(b) Price = (11.5 x 0.90909) + (11.5 x 0.81860) + (11.5 x 0.72969) + (111.5 x 0.64341)
= 100.00
Yield to maturity = 11.50% (the par yield is the same as the coupon because
the bond is priced at par)
(c) Price = (13 x 0.90909) + (13 x 0.81860) + (13 x 0.72969) + (113 x 0.64341)
= 104.65
Yield to maturity = 11.49% (using TVM function of HP calculator)
137
Part 2 · Interest Rate Instruments
1.1 ■ 1/x
1.10526 ENTER 2 ■ ∧ ■ 1/x
1.11076 ENTER 3 ■ ∧ ■ 1/x
1.11655 ENTER 4 ■ ∧ ■ 1/x
.90909 ENTER .8186 + .72969 + 5 ×
105 ENTER .64341 × +
FIN TVM +/- PV
4 N 5 PMT 100 FV I%YR
.90909 ENTER .8186 + .72969 + 11.5 ×
111.5 ENTER .64341 × +
.90909 ENTER .8186 + .72969 + 13 ×
113 ENTER .64341 × +
+/- PV 13 PMT I%YR
(1-year discount factor)
(2-year discount factor)
(3-year discount factor)
(4-year discount factor)
(Price of (a))
(Yield to maturity of (a))
(Price of (b))
(Price of (c))
(Yield to maturity of (c))
It can be seen from (b) above that if the zero-coupon discount factor for k
years is dfk, and the par yield for N years is i, it will always be the case that:
(i × df1) + (i × df2) + ....... + (i × dfN) + (1 × dfN) = 1
This gives: i × (df1 + df2 + ..... + dfN) = 1 – dfN
Therefore: i =
1 – dfN
N
∑ dfk
k=1
Calculation
summary
Par yield for N years =
1 – dfN
N
∑ dfk
k=1
where: dfk = zero-coupon discount factor for k years
Zero-coupon yields from coupon-bearing yields
In Example 6.1, we effectively calculated the 4-year par yield (11.50%) from
the series of zero-coupon yields. We can similarly calculate a zero-coupon
yield from a series of coupon-bearing yields. A method to do this is to build
up synthetic zero-coupon structures by combining a series of instruments
such that all the cashflows net to zero except for the first and the last.
Example 6.2
Suppose that the 1-year interest rate is 10% and that a series of bonds are
currently priced as follows:
Bond A
Bond B
Bond C
138
Price
97.409
85.256
104.651
Coupon
9
5
13
Maturity
2 years
3 years
4 years
6 · Zero-coupon Rates and Yield Curves
Consider a 2-year investment of 97.409 to purchase 100 face value of bond A and
a 1-year borrowing of 8.182 at 10.0%.
The cashflows are:
Year
0
1
2
– 97.409
+ 9.000
– 109.000
Net cashflows
– 89.227
+ 8.182
– 9.000
+ 109.000
In this way, we have constructed what is in effect a synthetic 2-year zero-coupon
instrument, because there are no cashflows between now and maturity. The
amount of 8.182 was calculated as the amount necessary to achieve 9.00 after
1 year – that is, the present value of 9.00 after 1 year.
The 2-year zero-coupon rate is therefore
109.00
( 89.227
)
1
–
2
– 1 = 10.526%
Next, consider a 3-year investment of 85.256 to purchase 100 face value of bond
B, a 1-year borrowing of 4.545 at 10.0% and a 2-year zero-coupon borrowing of
4.093 at 10.526%. The cashflows are:
Year
0
1
2
3
– 85.256
+ 5.000
+ 5.000
– 105.000
+ 4.545
– 5.000
+ 4.093
Net cashflows
– 76.618
– 5.000
+ 105.000
The 3-year zero-coupon rate is
( 105.00
)
76.618
1
–
3
– 1 = 11.076%
Again, 4.545 is the present value of 5.00 after 1 year; 4.093 is the present value of
5.00 after 2 years.
Finally, consider a 4-year investment of 104.651 to purchase 100 face value of
bond C, a 1-year borrowing of 11.818 at 10%, a 2-year zero-coupon borrowing of
10.642 at 10.526% and a 3-year zero-coupon borrowing of 9.486 at 11.076%. The
cashflows are:
Year
0
1
2
3
4
– 104.651
+ 13.000
+ 13.000
+ 13.000
+ 113.000
+ 11.818
– 13.000
The 4-year zero-coupon rate is
+ 10.642
+ 9.486
Net Cashflows
– 72.705
– 13.000
– 13.000
+ 113.000
( 113.000
)
72.705
1
–
4
– 1 = 11.655%
This process of building up a series of zero-coupon yields from coupon-bearing yields is known as “bootstrapping”. In Example 6.2, we used three bonds
as our starting point, none of which were priced at par. We could instead
have used bonds priced at par, or time deposits (which also return the same
original principal amount at maturity). In the case of interest rate swaps, for
example, we would indeed expect to have par swap rates as our starting
139
Part 2 · Interest Rate Instruments
point. The bootstrapping process is exactly the same, with initial cashflows
of 100 each instead of the non-par bond prices (97.409, 85.256 and
104.651) in Example 6.2. As long as we have four different investments, it is
possible to build a synthetic zero-coupon structure and hence calculate the
four-year, zero-coupon yield.
The zero-coupon rates calculated in Example 6.2 are in fact the same ones
as used in Example 6.1. We can see that the rates are consistent, in that in
Example 6.1, we have already used these zero-coupon rates to value the 4-year
13% coupon bond and arrived at the same price. The process is circular.
If all market prices and yields are consistent, it will not matter which existing bonds we use to construct the zero-coupon yields. In practice, however,
they will not be exactly consistent and it is generally preferable to use bonds
priced as closely as possible to par.
There are two more very important practical issues which we shall mention, but which are beyond the scope of this book. Firstly, it is not generally
possible in practice to find a series of existing bonds with the most convenient maturities – say 1 year, 2 years, 3 years, 4 years etc. – from which we
can construct the zero-coupon rates. Instead, we must use what are actually
available. Secondly, we need to interpolate between existing yields in order to
establish rates for all possible maturities. To do this, we must somehow fit a
curve along all the points. This requires assumptions to be made about the
mathematical nature of the curve, and some degree of compromise in order
to make the curve smooth.
FORWARD-FORWARD YIELDS
Constructing forward-forward yields from zero-coupon yields
In Chapter 3, we constructed short-term forward-forward rates from a series
of “normal” rates for periods beginning now. Exactly the same approach can
be used for constructing long-term, forward-forward yields from long-term,
zero-coupon yields.
Example 6. 3
Suppose the same zero-coupon curve as in Example 6.3. What are the 1-year v
2-year forward-forward yield, the 2-year v 3-year forward-forward yield and
the 1-year v 3-year forward-forward zero-coupon yield?
Using the 1-year zero-coupon rate of 10.000%, an amount of 1 now has a future
value after 1 year of 1.10000.
Using the 2-year zero coupon rate of 10.526%, an amount of 1 now has a future
value after 2 years of (1.10526)2.
It follows that an amount worth 1.1000 after 1 year is worth (1.10526)2 after 2 years.
The yield linking these two amounts over that 1-year forward-forward period is:
(1.10526)2
– 1 = 11.055%
(1.10000)
140
6 · Zero-coupon Rates and Yield Curves
This is therefore the 1-year v 2-year forward-forward yield.
Using the 3-year zero-coupon rate of 11.076%, an amount of 1 now has a future
value after 3 years of (1.11076)3
The 2-year v 3-year forward-forward rate is therefore:
(1.11076)3
– 1 = 12.184%
(1.10526)2
The relationship between an amount after 1 year and an amount after 3 years is:
(1.11076)3
= 1.2459
(1.10000)
The 1-year v 3-year zero-coupon forward-forward is therefore:
1
(1.2459) /2 – 1 = 11.618%
In general, if zk and zm are the zero-coupon yields for k years and m years
respectively, we have the following:
Forward-forward zero-coupon yield from k years to m years is:
[
(1 + zm)m
(1 + zk)k
]
Calculation
summary
1
(m–k)
–1
In particular, the forward-forward yield from k years to (k + 1) years is:
(1 + zk+1)k+1
(1 + zk)k
–1
Zero-coupon yields from forward-forward yields
In Chapter 3, we first used “normal” interest rates to calculate forward-forward rates. We then said that this approach could be reversed. It may make
more sense to begin with the question: what does the market expect interest
rates to be in the future? From this, we can construct a series of “normal” rates.
Exactly the same question arises with long-term, forward-forward yields
and zero-coupon yields.
Example 6.4
The 1-year interest rate is now 10%. The market expects 1-year rates to rise to
11.05% after one year and to 12.18% after a further year. What would you expect
the current 2-year and 3-year zero-coupon yields to be, consistent with these
expectations?
An amount of 1 now will be worth (1 + 10%) = 1.10 after one year. This is expected
to increase by a further 11.05% and 12.18% in the following two years. We can
therefore construct a strip of rates for the expected value at the end of three years:
141
Part 2 · Interest Rate Instruments
1.10 × 1.1105 × 1.1218 = 1.3703
The 3-year zero coupon rate should therefore be:
( 1.3703
)
1
1
–
3
– 1 = 11.07%
The result of Example 6.4 is consistent with our earlier examples, demonstrating that we could begin with a forward-forward yield curve (that is, a
series of 1-year, forward-forward rates), create from them a consistent zerocoupon yield curve, and then create a consistent par yield curve.
Calculation
summary
1
zk = [(1 + i1) × (1 + i2) × (1 + i3) × ....... × (1 + ik)] k – 1
where: i1, i2, i3 ... ik are the 1-year cash interest rate and the 1-year v
2-year, 2-year v 3-year, ... (k –1)-year v k-year forward-forward rates
SUMMARY
Although all the yields we have considered should in theory be consistent,
actual market yields might not be. This is important for bond valuation. A
bond trading in the market has an actual known market price at which
traders are willing to sell it. An investor can calculate the yield to maturity
implied by this price and decide whether he/she considers the bond a good
investment. However, he/she can also calculate what the theoretical price
should be if all the bond’s cashflows are individually valued to an NPV using
a series of separate zero-coupon rates. The result may in practice be different
from the actual market price. The investor then needs to decide whether, if
the theoretical price is lower, he/she considers the bond overpriced.
Generally, there is no exact arbitrage to bring the market price precisely in
line with this theoretical price, because there are no corresponding zerocoupon instruments. The zero-coupon yields are themselves often theoretical.
It is therefore often more a question of using zero-coupon yields to compare
different bonds, to see which is better value at current market prices. In the
case of government securities where the bonds themselves can be stripped,
however, a direct comparison can be made between the price of the bond
and the prices of its stripped components, so that the arbitrage is possible.
Calculation
summary
Conversion between yield curves
• To create a zero-coupon yield from coupon-bearing yields: bootstrap
• To calculate the yield to maturity on a non-par coupon-bearing bond
from zero-coupon yields: calculate the NPV of the bond using the zerocoupon yields, then calculate the yield to maturity of the bond from this
dirty price
• To create a par yield from zero-coupon yields: use the formula above
142
6 · Zero-coupon Rates and Yield Curves
• To create a forward-forward yield from zero-coupon yields: use the
formula above
• To create a zero-coupon yield from forward-forward yields: create a
strip of the first cash leg with a series of forward-forwards
A par yield curve tends to be exaggerated by the corresponding zero-coupon
curve. That is, a positive par yield curve is reflected by a more positive zerocoupon curve and a negative par yield curve by a more negative zero-coupon
curve. The forward-forward curve tends to exaggerate further a change in
shape of the zero-coupon curve (see Figure 6.1).
Comparison between par, zero-coupon and forward-forward yields
Fig 6.1
15
14
13
Yield %
12
11
10
9
8
7
Forward-forward
Zero-coupon
Par
6
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Maturity in years
LONGER-DATED FRAS
In Chapter 3, we considered FRAs up to one year. For FRAs beyond a year,
the calculation of a theoretical FRA price is complicated by the fact that
deposits over one year generally pay some interest at the end of the first year
or each six months. There are two approaches to this. The first is to consider
all the cashflows involved; the second is to calculate zero-coupon discount
factors and then use these to calculate an FRA rate.
Example 6.5
Given the following interest rates, what is the theoretical 15 v 18 FRA rate? All rates
are on an ACT/360 basis.
12 months (365 days):
15 months (456 days):
18 months (548 days):
8.5%
8.6% (interest paid after 12 months and 15 months)
8.7% (interest paid after 12 months and 18 months)
First approach
Consider an amount of 1 deposited for 12 months, rolled over at the 12 v 18 FRA
rate. The result after 18 months will be:
143
Part 2 · Interest Rate Instruments
183
× 1 + [12 v 18 FRA] ×
(1 + 0.085 × 365
360 ) (
360 )
The same result should be achieved by depositing for 18 months and rolling over
the interim interest payment (received after 12 months) at the 12 v 18 FRA rate:
[
1 + 0.087 ×
)] + [ 0.087 × 183
360 ]
365
183
× 1 + [12 v 18 FRA] ×
360
360
(
If these two are equal, we can calculate the 12 v 18 FRA as:
12 v 18 FRA =
[(
183
(1 + 0.087 × 360
)
365
365
1 + 0.085 × 360
– 0.087 × 360
)
]
–1 ×
360
= 9.1174%
183
The same result should also be achieved by depositing for 15 months and rolling
over at the 15 v 18 FRA rate, with the interim interest payment (received after 12
months) rolled over from 12 months to 18 months at the 12 v 18 FRA rate. The
result after 18 months will be:
[
0.086 ×
(
)] [(
) (
365
183
91
92
× 1 + 0.091174 ×
+ 1 + 0.086 ×
+ 1 + [15 v 18 FRA] ×
360
360
360
360
)]
If this is equal to the first result, we have:
15 v 18 FRA =
[
365
183
365
183
× (1 + 0.091174 × 360
(1 + 0.085 × 360
) × (1 + 0.091174 × 360
) – [0.086 × 360
)
–1
91
(1 + 0.086 × 360)
]
×360
92
= 9.02%
Second approach
The 12-month discount factor is
1
(1 + 0.085 ×
365
360
)
= 0.92066
Consider the following cashflows (a 15-month deposit and a 12-month borrowing):
Months
0
365
+(8.6 × 360
— × 0.92066)
–100
12
365
—)
+(8.6 × 360
15
+(100 + 8.6 ×
Net
– 91.9724
365
– (8.6 × 360
—)
91
—
360
The 15-month discount factor is
)
+ 102.1739
91.9724
= 0.90016
102.1739
Now consider the following cashflows (an 18-month deposit and a 12-month
borrowing):
Months
0
144
–100
365
+(8.7 × 360
— × 0.92066)
12
365
—)
+(8.7 × 360
365
– (8.7 × 360
—)
18
183
— )
+(100 + 8.7 × 360
Net
– 91.8790
+ 104.4225
6 · Zero-coupon Rates and Yield Curves
The 18-month discount factor is
The 15 v 18 FRA therefore
[
91.8790
= 0.87988
104.4225
1
0.87988
–
1
0.90016
]
1 ×
360
= 9.02 %
92
The two approaches are effectively the same; the second is rather more structured.
145
Part 2 · Interest Rate Instruments
EXERCISES
58. Calculate the 2-year, 3-year and 4-year zero-coupon yields and discount factors consistent with the following bonds. The 1-year yield is 10.00%.
Maturity
2 years
3 years
4 years
Coupon
9.0% (annual)
7.0% (annual)
11.0% (annual)
Price
97.70
90.90
99.40
What are the 1-year v 2-year, 2-year v 3-year and 3-year v 4-year forwardforward yields?
59. The forward-forward curve is as follows:
1-year yield:
1-year v 2-year:
2-year v 3-year:
3-year v 4-year:
8.00%
8.24%
9.00%
9.50%
a. Calculate the 2-year, 3-year and 4-year zero-coupon yields and par yields.
b. What is the yield to maturity of a 4-year 12% annual coupon bond, consistent with the rates above?
60. What is the 18 v 24 FRA rate based on the following? All rates are ACT/360.
6 months (182 days):
12 months (365 days):
18 months (548 days):
24 months (730 days):
146
8.60% / 8.70%
8.70% / 8.80%
8.80% / 8.90% (interest paid 6-monthly)
8.90% / 9.00% (interest paid 6-monthly)
Part 3
Foreign Exchange
147
■
■
■
“A forward foreign exchange
swap is a temporary purchase
or sale of one currency against
another. An equivalent effect
could be achieved by borrowing
one currency, while lending
the other.”
148
7
Foreign Exchange
Introduction
Spot exchange rates
Forward exchange rates
Cross-rate forwards
Short dates
Calculation summary
Value dates
Forward-forwards
Time options
Long-dated forwards
Synthetic agreements for forward exchange (SAFEs)
Arbitraging and creating FRAs
Discounting future foreign exchange risk
Exercises
149
Part 3 · Foreign Exchange
INTRODUCTION
Throughout this chapter, we have generally used ISO codes (also used by the
SWIFT system) to abbreviate currency names. You can find a list of the codes
in Appendix 5 for reference.
A convention has also been used that, for example, the US dollar/
Deutschemark exchange rate is written as USD/DEM if it refers to the
number of Deutschemarks equal to 1 US dollar and DEM/USD if it refers to
the number of US dollars equal to 1 Deutschemark. The currency code written on the left is the “base” currency; there is always 1 of the base unit. The
currency code written on the right is the “variable” currency (or “counter”
currency or “quoted” currency). The number of units of this currency equal
to 1 of the base currency varies according to the exchange rate. Although
some people do use the precisely opposite convention, the one we use here is
the more common. The important point to remember is to be consistent.
SPOT EXCHANGE RATES
A “spot” transaction is an outright purchase or sale of one currency for
another currency, for delivery two working days after the dealing date (the
date on which the contract is made). This allows time for the necessary
paperwork and cash transfers to be arranged. Normally, therefore, if a spot
deal is contracted on Monday, Tuesday or Wednesday, delivery will be two
days after (i.e. Wednesday, Thursday or Friday respectively). If a spot deal is
contracted on a Thursday or Friday, the delivery date is on Monday or
Tuesday respectively, as neither Saturday nor Sunday are working days in the
major markets.
There are, however, some exceptions. For example, a price for USD/CAD
without qualification generally implies delivery on the next working day after
the dealing day. This is referred to as “funds”. A “spot” price (value two
working days after the dealing day, as usual) can generally be requested as an
alternative. USD/HKD is also often traded for value the next working day (a
“TT” price). Another problem arises in trading Middle East currencies where
the relevant markets are closed on Friday but open on Saturday. A USD/SAR
spot deal on Wednesday would need to have a split settlement date: the USD
would be settled on Friday, but the SAR on Saturday.
If the spot date falls on a public holiday in one or both of the centres of
the two currencies involved, the next working day is taken as the value date.
For example, if a spot GBP/USD deal is transacted on Thursday 31 August, it
would normally be for value Monday 4 September. If this date is a holiday in
the UK or the USA, however, all spot transactions on Thursday 31 August
are for value Tuesday 5 September. If the intervening day (between today
and spot) is a holiday in one only of the two centres, the spot value date is
usually also delayed by one day.
150
7 · Foreign Exchange
How spot rates are quoted
In the spot market, a variable number of units of one currency is quoted per
one unit of another currency. When quoting against the US dollar, it is the
practice in the interbank market to quote most currencies in terms of a varying number of units of currency per 1 US dollar. This is known as an
“indirect” or “European” quotation against the dollar. Rates quoted the
opposite way round are known as “direct” quotations against the dollar.
There are some currencies which are conventionally quoted against the
USD “direct” rather than “indirect.” The major ones are sterling, Australian
dollar, New Zealand dollar, Irish pound and ECU (European currency unit –
to be replaced by the proposed euro).
The Canadian dollar is now generally quoted in indirect terms, although a
direct quotation is possible. The direct quotation for the Canadian dollar is
known as “Canada cross” and the indirect quotation “Canada funds.”
In the currency futures markets, as opposed to the interbank market, all
quotations against the US dollar are direct.
Although dealing is possible between any two convertible currencies – for
example, Malaysian ringgits against Deutschemarks or French francs against
Japanese yen – the interbank market historically quoted mostly against US
dollars, so reducing the number of individual rates that needed to be quoted.
The exchange rate between any two non-US dollar currencies could then be
calculated from the rate for each currency against US dollars. A rate between
any two currencies, neither of which is the dollar, is known as a cross-rate.
Cross-rates (for example, sterling/Deutschemark, Deutschemark/yen,
Deutschemark/Swiss franc) have however increasingly been traded between
banks in addition to the dollar-based rates. This reflects the importance of
the relationship between the pair of currencies. The economic relationship
between the French franc and the Deutschemark, for example, is clearly
closer than the relationship between the French franc and the dollar. It is
therefore more true nowadays to say that the dollar/franc exchange rate is a
function of the dollar/Deutschemark rate and the Deutschemark/franc rate,
rather than that the Deutschemark/franc rate is a function of the
dollar/Deutschemark rate and the dollar/franc rate. However, the principle of
calculating cross-rates remains the same.
As in other markets, a bank normally quotes a two-way price, whereby it
indicates at what level it is prepared to buy the base currency against the
variable currency (the “bid” for the base currency – a cheaper rate), and at
what level it is prepared to sell the base currency against the variable currency (the “offer” of the base currency – a more expensive rate). For
example, if a bank is prepared to buy dollars for 1.6375 Deutschemarks, and
sell dollars for 1.6385 Deutschemarks, the USD/DEM rate would be quoted
as: 1.6375 / 1.6385.
The quoting bank buys the base currency (in this case, dollars) on the left
and sells the base currency on the right. If the bank quotes such a rate to a
company or other counterparty, the counterparty would sell the base currency on the left, and buy the base currency on the right – the opposite of
how the bank sees the deal.
151
Part 3 · Foreign Exchange
In the money market, the order of quotation is not important and it does
differ between markets. From a quotation of either “5.80% / 5.85%” or
“5.85% / 5.80%”, it is always clear to the customer that the higher rate is the
offered rate and the lower rate is the bid rate. In foreign exchange, however,
the market-maker’s bid for the base currency (the lower number in a spot
price) is always on the left. This is particularly important in forward prices.
The difference between the two sides of the quotation is known as the
“spread.” Historically, a two-way price in a cross-rate would have a wider
spread than a two-way price in a dollar-based rate, because the cross-rate
constructed from the dollar-based rates would combine both the spreads.
Now, however, the spread in, say, a Deutschemark/French franc price would
typically be narrower than a dollar/franc spread, because it is now the
Deutschemark/franc price that is “driving” the market, as noted above,
rather than the dollar/franc price.
Any indirect quotation against the dollar can be converted into a direct
quotation by taking its reciprocal. Thus, a USD/DEM quotation of 1.6375 /
1.6385 can be converted to a DEM/USD quotation of (1 ÷ 1.6375) / (1 ÷
1.6385). However, this would still be quoted with a smaller number on the
left, so that the two sides of the quotation are reversed: 0.6103 / 0.6107. The
important difference is thus that in a direct quotation the bank buys the
other currency against the US dollar on the left, sells the other currency
against the US dollars on the right – the reverse of an indirect quotation.
Rates are normally quoted to –
œqππ th of a pfennig, cent, etc. (known as a
“point” or a “pip”). Thus the US dollar/Deutschemark rate would usually be
quoted as 1.6375 / 1.6385, for example. This depends on the size of the number,
however, and some typical examples where fewer decimal places are used are:
USD/JPY
USD/BEF
105.05 / 15
34.095 / 125
USD/ITL
USD/ESP
1752.00 / 50
139.80 / 85
In the case of USD/JPY, for example, “15 points” means 0.15 yen.
As the first three digits of the exchange rate (known as the “big figure”) do
not change in the short term, dealers generally do not mention them when dealing in the interbank market. In the example above (1.6375 / 1.6385), the
quotation would therefore be given as simply 75 / 85. However, when dealers
are quoting a rate to a corporate client they will often mention the big figure
also. In this case, the quotation would be 1.6375 / 85.
As the market moves very quickly, dealers need to deal with great speed
and therefore abbreviate when dealing. For example, if one dealer wishes to
buy USD 5 million from another who is quoting him a USD/DEM price, he
will say simply “5 mine;” this means “I wish to buy from you 5 million of
the base currency and sell the other currency, at your offered price.”
Similarly, if he wishes to sell USD 5 million, he will say simply “5 yours,”
meaning “I wish to sell you 5 million of the base currency and buy the other
currency, at your bid price.”
To earn profit from dealing, the bank’s objective is clearly to sell the US
dollars at the highest rate it can against the variable currency and buy US
dollars at the lowest rate.
152
7 · Foreign Exchange
Example 7.1
Deal 1:
Bank buys USD 1,000,000 against DEM at 1.6830
Deal 2:
Bank sells USD 1,000,000 against DEM at 1.6855
Inflows
Outflows
Deal 1:
USD 1,000,000
DEM 1,683,000
Deal 2:
DEM 1,685,500
USD 1,000,000
Net result:
DEM
2,500
Dealers generally operate on the basis of small percentage profits but large
turnover. These rates will be good for large, round amounts. For very large
amounts, or for smaller amounts, a bank would normally quote a wider
spread. The amount for which a quotation is “good” (that is, a valid quote
on which the dealer will deal) will vary to some extent with the currency concerned and market conditions.
Cross-rates
In most cases, there is not a universal convention for which way round to quote
a cross-rate – that is, which is the base currency and which the variable currency.
If a rate between DEM and FRF is requested “in FRF terms”, for example, this
would generally mean that FRF is the base and DEM the variable.
Example 7.2
Suppose that we need to quote to a counterparty a spot rate between the
Deutschemark and the ringgit, and that our bank does not have a DEM/MYR trading book. The rate must therefore be constructed from the prices quoted by our
bank’s USD/DEM dealer and our bank’s USD/MYR dealer as follows:
Spot USD/DEM:
Spot USD/MYR:
1.6874 / 1.6879
2.4782 / 2.4792
Consider first the left side of the final DEM/MYR price we are constructing. This is
the price at which our bank will buy DEM (the base currency) and sell MYR. We
must therefore ask: at which price (1.6874 or 1.6879) does our USD/DEM dealer
buy DEM against USD, and at which price (2.4782 or 2.4792) does our USD/MYR
dealer sell MYR against USD? The answers are 1.6879 (on the right) and 2.4782
(on the left) respectively. Effectively, by dealing at these prices, our bank is both
selling USD (against DEM) and buying USD (against MYR) simultaneously, with a
net zero effect in USD. If we now consider the right side of the final DEM/MYR
price we are constructing, this will come from selling DEM against USD (on the left
at 1.6874) and buying MYR against USD (on the right at 2.4792). Finally, since each
1 dollar is worth 1.68 Deutschemarks and also 2.47 ringgits, the DEM/MYR
exchange rate must be the ratio between these two:
2.4782 ÷ 1.6879 = 1.4682 is how the bank sells MYR and buys DEM
2.4792 ÷ 1.6874 = 1.4692 is how the bank buys MYR and sells DEM
Therefore the spot DEM/MYR rate is: 1.4682 / 1.4692.
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Part 3 · Foreign Exchange
In summary, therefore, to calculate a spot cross-rate between two indirect
dollar rates, divide opposite sides of the exchange rates against the US dollar.
Following the same logic shows that to calculate a spot cross-rate between
two direct dollar rates, we again need to divide opposite sides of the
exchange rates against the US dollar.
Example 7.3
Spot GBP/USD: 1.6166 / 1.6171
Spot AUD/USD: 0.7834 / 0.7839
The GBP/USD dealer buys GBP and sells USD at 1.6166 (on the left).
The AUD/USD dealer sells AUD and buys USD at 0.7839 (on the right).
Therefore:
1.6166 ÷ 0.7839 = 2.0623 is how the bank sells AUD and buys GBP
Similarly:
1.6171 ÷ 0.7834 = 2.0642 is how the bank buys AUD and sells GBP
Therefore the spot GBP/AUD rate is: 2.0623 / 2.0642.
Finally, to calculate a cross-rate between a direct rate and an indirect rate,
following the same logic through again shows that we multiply the same
sides of the exchange rates against the US dollar.
Example 7.4
Spot USD/DEM: 1.6874 / 1.6879
Spot AUD/USD: 0.7834 / 0.7839
The USD/DEM dealer buys USD and sells DEM at 1.6874 (on the left).
The AUD/USD dealer buys AUD and sells USD at 0.7834 (on the left).
Also, since each 1 Australian dollar is worth 0.78 US dollars, and each of these US
dollars is worth 1.68 Deutschemarks, the AUD/DEM exchange rate must be the
product of these two numbers. Therefore:
1.6874 × 0.7834 = 1.3219 is how the bank sells DEM and buys AUD
Similarly:
1.6879 x 0.7839 = 1.3231 is how the bank buys DEM and sells AUD
Therefore the spot AUD/DEM rate is: 1.3219 / 1.3231.
Calculation
summary
To calculate cross-rates from dollar rates
• Between two indirect rates or two direct rates: divide opposite sides of
the dollar exchange rates
• Between one indirect rate and one direct rate: multiply the same sides of
the dollar exchange rates
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7 · Foreign Exchange
It is just as important to be able to construct rates from non-dollar rates. The
same logic, considering the way in which each of the two separate dealers
will deal to create the cross-rate, gives the construction:
Example 7.5
Spot USD/DEM: 1.6874 / 1.6879
Spot DEM/FRF: 3.3702 / 3.3707
Spot DEM/SEK: 4.5270 / 4.5300
(i)
To construct spot FRF/SEK:
4.5270 ÷ 3.3707 = 1.3430 is how the bank buys FRF and sells SEK
4.5300 ÷ 3.3702 = 1.3441 is how the bank sells FRF and buys SEK
Therefore the spot FRF/SEK rate is: 1.3430 / 1.3441.
(ii) To construct spot SEK/FRF:
3.3702 ÷ 4.5300 = 0.7440 is how the bank buys SEK and sells FRF
3.3707 ÷ 4.5270 = 0.7446 is how the bank sells SEK and buys FRF
Therefore the spot SEK/FRF is 0.7440 / 0.7446.
(iii) To construct spot USD/FRF:
1.6874 × 3.3702 = 5.6869 is how the bank buys USD and sells FRF
1.6879 × 3.3707 = 5.6894 is how the bank sells USD and buys FRF
Therefore the spot USD/FRF rate is: 5.6869 / 5.6894.
(iv) To construct spot FRF/USD, take the reciprocal of the USD/FRF:
1 ÷ (1.6879 × 3.3707) = 0.17577 is how the bank buys FRF and sells USD
1 ÷ (1.6874 × 3.3702) = 0.17584 is how the bank sells FRF and buys USD
Therefore the spot FRF/USD rate is 0.17577 / 0.17584.
The construction of one exchange rate from two others in this way can be
seen “algebraically”:
Given two exchange rates A/B and A/C, the cross-rates are:
Calculation
summary
B/C = A/C ÷ A/B
and C/B = A/B ÷ A/C
Given two exchange rates B/A and A/C, the cross-rates are:
B/C = B/A × A/C
and C/B = 1 ÷ (B/A × A/C)
When dividing, use opposite sides. When multiplying, use the same sides.
155
Part 3 · Foreign Exchange
FORWARD EXCHANGE RATES
Forward outrights
Although “spot” is settled two working days in the future, it is not considered in the foreign exchange market as “future” or “forward”, but as the
baseline from which all other dates (earlier or later) are considered.
A “forward outright” is an outright purchase or sale of one currency in
exchange for another currency for settlement on a fixed date in the future
other than the spot value date. Rates are quoted in a similar way to those in
the spot market, with the bank buying the base currency “low” (on the left
side) and selling it “high” (on the right side). In some emerging markets, forward outrights are non-deliverable and are settled in cash against the spot
rate at maturity as a contract for differences.
Example 7.6
The spot USD/DEM rate is 1.6874 / 1.6879, but the rate for value one month after
the spot value date is 1.6844 / 1.6851.
The “spread” (the difference between the bank’s buying price and the bank’s selling price) is wider in the forward quotation than in the spot quotation. Also, in this
example, the US dollar is worth less in the future than at the spot date. USD 1 buys
DEM 1.6844 in one month’s time as opposed to 1.6874 at present. In a different
example, the US dollar might be worth more in the future than at the spot date.
The forward outright rate may be seen both as the market’s assessment of
where the spot rate will be in the future and as a reflection of current interest
rates in the two currencies concerned.
Consider, for example, the following “round trip” transactions, all undertaken simultaneously:
(i)
(ii)
(iii)
(iv)
Borrow Deutschemarks for 3 months starting from spot value date.
Sell Deutschemarks and buy US dollars for value spot.
Deposit the purchased dollars for 3 months starting from spot value date.
Sell forward now the dollar principal and interest which mature in
3 months’ time, into Deutschemarks.
In general, the market will adjust the forward price for (iv) so that these
simultaneous transactions generate neither a profit nor a loss. When the four
rates involved are not in line (DEM interest rate, USD/DEM spot rate, USD
interest rate and USD/DEM forward rate), there is in fact opportunity for
arbitrage – making a profit by round-tripping. That is, either the transactions
as shown above will produce a profit or exactly the reverse transactions
(borrow $, sell $ spot, deposit DEM, sell DEM forward) will produce a profit.
The supply and demand effect of this arbitrage activity is such as to move the
rates back into line. If in fact this results in a forward rate which is out of line
with the market’s “average” view, supply and demand pressure will tend to
move the spot rate or the interest rates until this is no longer the case.
In more detail, the transactions might be as follows:
(i)
156
Borrow DEM 100 at an interest rate of v per annum. The principal and
interest payment at maturity will be:
7 · Foreign Exchange
(
100 × 1 + v ×
days
360
)
(ii) Sell DEM 100 for USD at spot rate to give USD (100 ÷ spot).
(iii) Invest USD (100 ÷ spot) at an interest rate of b per annum. The principal and interest returned at maturity will be:
(
(100 ÷ spot) × 1 + b ×
days
360
)
(iv) Sell forward this last amount at the forward exchange rate to give:
(
DEM (100 ÷ spot) × 1 + b ×
)
days
× forward outright
360
Arbitrage activity will tend to make this the same amount as that in (i),
so that:
forward outright = spot ×
(1 + v × days
360)
days
(1 + b × 360)
(1 + variable currency interest rate × days
year)
Forward outright = spot ×
days
(1 + base currency interest rate × year)
Calculation
summary
Notice that the length of the year may be 360 or 365, depending on each currency.
Example 7.7
31-day DEM interest rate:
31-day USD interest rate:
Spot USD/DEM rate:
3%
5%
1.6876
Then forward outright = 1.6876 ×
(1 + 0.03 × ) = 1.6847
(1 + 0.05 × )
31
360
31
360
.03 ENTER 31 × 360 ÷ 1 +
.05 ENTER 31 × 360 ÷ 1 + ÷
1.6876 ×
Forward swaps
Although forward outrights are an important instrument, banks do not in
practice deal between themselves in forward outrights, but rather in forward
“swaps”, where a forward swap is the difference between the spot and the
forward outright. The reason for not dealing in outrights will become clear
later. The forward outright rate can therefore be seen as a combination of the
current spot rate and the forward swap rate (which may be positive or negative) added together.
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Part 3 · Foreign Exchange
Key Point
Forward outright = spot + forward swap
Example 7.8
Spot USD/DEM: 1.6874 / 1.6879
Forward swap: 0.0145 / 0.0150
Forward outright: 1.7019 / 1.7029
Forward outright = spot + swap
In this case: 1.7019 = 1.6874 + 0.0145
1.7029 = 1.6879 + 0.0150
In the previous section, we saw that:
(1 + variable currency interest rate × days
year)
forward outright = spot ×
(1 + base currency interest rate × days
year )
Since we know that:
forward swap = forward outright – spot
it follows that:
Calculation
summary
Forward swap =
spot ×
– base currency interest rate × days
(variable currency interest rate × days
year
year )
days
( 1 + base currency interest rate × year)
As before, the length of each year may be 360 or 365 days. If the year basis
is the same for the two currencies and the number of days is sufficiently
small, so that the denominator in the last equation is close to 1, the following
approximation holds:
Calculation
summary
Approximation
~ spot × interest rate differential ×
Forward swap ~
days
year
In reverse, one can calculate an approximate interest rate differential from
the swap rate as follows:
Calculation
summary
158
Approximation
~ forward swap × year
Interest rate differential ~
spot
days
7 · Foreign Exchange
Example 7.9
31-day DEM interest rate:
31-day USD interest rate:
Spot USD/DEM rate:
3%
5%
1.6876
Forward swap = 1.6876 ×
0.03 ×
31
360
– 0.05 ×
1 + 0.05 ×
31
360
31
360
= – 0.0029 or – 29 points
Approximate swap = 1.6876 × (–0.02) ×
31
( 360
) = –29 points
Example 7.10 shows that the approximation is generally not accurate
enough for longer periods.
Example 7.10
1-year DEM interest rate:
1-year USD interest rate:
Spot USD/DEM rate:
3%
10%
1.6876
Forward swap = 1.6876 ×
365
365
0.03 × 360
– 0.10 × 360
365
1 + 0.10 × 360
= – 0.1087 or – 1087 points
Approximate swap = 1.6876 × (–0.07) ×
365
= –1198 points
360
Swap prices are quoted as two-way prices in the same way as other prices. In
theory, one could use a borrowing rate for Deutschemarks and a deposit rate
for US dollars in Example 7.10, to calculate the swap prices where the bank
buys US dollars from the customer against Deutschemarks for spot value,
and simultaneously sells US dollars to the customer against Deutschemarks
for value one month forward. One could then use the deposit rate for
Deutschemarks and the borrowing rate for US dollars to determine the other
side of the price. However, this would produce a rather large spread. It is
more realistic to use middle prices throughout, to calculate a middle price for
the swap, and then to spread the two-way swap price around this middle
price. In practice, a dealer does not recalculate swap prices continually in any
case, but takes them from the market just as the spot dealer takes spot prices.
Discounts and premiums
It can be seen from the formulas given above that when the base currency
interest rate is higher than the variable currency rate, the forward outright
exchange rate is always less than the spot rate. That is, the base currency is
worth fewer forward units of the variable currency forward than it is spot.
This can be seen as compensating for the higher interest rate: if I deposit
money in the base currency rather than the variable currency, I will receive
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Part 3 · Foreign Exchange
more interest. However, if I try to lock in this advantage by selling forward
the maturing deposit amount, the forward exchange rate is correspondingly
worse. In this case, the base currency is said to be at a “discount” to the variable currency, and the forward swap price must be negative.
The reverse also follows. In general, given two currencies, the currency
with the higher interest rate is at a “discount” (worth fewer units of the other
currency forward than spot) and the currency with the lower interest rate is
at a “premium” (worth more units of the other currency forward than spot).
When the variable currency is at a premium to the base currency, the forward swap points are negative; when the variable currency is at a discount to
the base currency, the forward swap points are positive.
When the swap points are positive, and the forward dealer applies a
bid/offer spread to make a two-way swap price, the left price is smaller than
the right price as usual. When the swap points are negative, he must similarly
quote a “more negative” number on the left and a “more positive” number on
the right in order to make a profit. However, the minus sign “ – ” is generally
not shown. The result is that the larger number appears to be on the left. As a
result, whenever the swap price appears larger on the left than the right, it is in
fact negative, and must be subtracted from the swap rate rather than added.
Example 7.11
German interest rate:
US interest rate:
DEM is at a premium to USD
USD is at a discount to DEM
Forward swap points are negative.
3%
5%
Swap prices are generally quoted so that the last digit of the price coincides
with the same decimal place as the last digit of the spot price. For example, if
the spot price is quoted to four decimal places (1.6874) and the swap price is
“30 points,” this means “0.0030.”
Example 7.12
The Deutschemark is at a premium to the US dollar, and the swap rate is quoted
as 30 / 28.
Spot USD/DEM:
1-month swap:
1-month outright:
1.6874 /
79
30 /
28
1.6844 / 1.6851
The spot US dollar will purchase DEM1.6874; the forward US dollar will purchase
DEM1.6844. The dollar is therefore worth less in the future, and is thus at a forward
discount.
Example 7.13
Spot USD/ITL:
1-month swap:
1-month outright:
160
1782.00 / 1784.00
2.30 /
2.80
1784.30 / 1786.80
7 · Foreign Exchange
The spot US dollar will purchase ITL 1782.00; the forward US dollar will purchase
ITL 1784.30. The dollar is therefore worth more in the future and is thus at a forward premium.
If a forward swap price includes the word “par” it means that the spot rate
and the forward outright rate are the same: “par” in this case represents
zero. A/P is “around par”, meaning that the left-hand side of the swap must
be subtracted from spot and the right-hand side added.
Example 7.14
Spot BEF:
1-year swap:
Forward outright:
31.98 /
00
6 /
6 A/P
31.92 / 32.06
This is often written –6 / +6, which means the same as 6 / 6 A/P but indicates
more clearly how the outrights are calculated.
Terminology
It is important to be careful about the terminology regarding premiums and
discounts. The clearest terminology, for example, is to say that “the DEM is
at a premium to the USD” or that “the USD is at a discount to the DEM;”
then there is no ambiguity. If, however, a dealer says that “the USD/DEM is
at a discount,” he generally means that the variable currency, DEM, is at a
discount and that the swap points are to be added to the spot. Similarly, if he
says that “the GBP/FRF is at a premium,” he means that the variable currency, FRF, is at a premium and that the points are to be subtracted from the
spot. If there is no qualification, he is generally referring to the variable currency, not the base currency.
A forward swap position
In order to see why a bank trades in forward swaps rather than forward outrights, consider how the following swap and outright rates change as the spot
rate and interest rates move:
spot rate
1.6876
1.6976
1.6976
USD
interest rate
DEM
interest rate
31-day
forward outright
31-day
forward swap
5.0%
5.0%
5.5%
3.0%
3.0%
3.0%
1.6847
1.6947
1.6940
– 0.0029
– 0.0029
– 0.0036
A movement of 100 points in the exchange rate from 1.6876 to 1.6976 has
not affected the forward swap price (to 4 decimal places). However, a change
in the interest rate differential from 2.0 percent to 2.5 percent has changed it
significantly. Essentially, a forward swap is an interest rate instrument rather
than a currency instrument; when banks take forward positions, they are
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Part 3 · Foreign Exchange
taking an interest rate view rather than a currency view. If bank dealers
traded outrights, they would be combining two related but different markets
in one deal, which is less satisfactory.
When a bank quotes a swap rate, it quotes in a similar manner to a spot
rate. The bank buys the base currency forward on the left, and sells the base
currency forward on the right.
The forward swap deal itself is an exchange of one currency for another
currency on one date, to be reversed on a given future date. Thus, for example, when the bank sells USD outright to a counterparty, it may be seen as
doing the following:
Bank’s spot dealer sells USD spot
Bank’s forward dealer buys USD spot
Bank’s forward dealer sells USD forward
spot deal
}
Bank sells USD forward outright
forward swap deal
net effect
Therefore on a USD/DEM 1-month forward swap quote of 30 / 28, the bank
quoting the price does the following:
30
/
sells USD spot
buys USD forward
28
buys USD spot
sells USD forward
A forward foreign exchange swap is therefore a temporary purchase or sale
of one currency against another. An equivalent effect could be achieved by
borrowing one currency for a given period, while lending the other currency
for the same period. This is why the swap rate formula reflects the interest
rate differential (generally based on Eurocurrency interest rates rather than
domestic interest rates) between the two currencies, converted into foreign
exchange terms.
If a forward dealer has undertaken a similar deal to the one above –
bought and sold USD (in that order) as a speculative position – what interest
rate view has he taken? He has effectively borrowed dollars and lent
Deutschemarks for the period. He probably expects USD interest rates to rise
(so that he can relend them at a higher rate) and/or DEM rates to fall (so that
he can reborrow them at a lower rate). In fact, the important point is that the
interest differential should move in the USD’s favour. For example, even if
USD interest rates fall rather than rise, the dealer will still make a profit as
long as DEM rates fall even further.
Although only one single price is dealt (the swap price), the transaction
has two separate settlements:
• a settlement on the spot value date
• a settlement on the forward value date
There is no net outright position taken, and the spot dealer’s spread will not
be involved, but some benchmark spot rate will nevertheless be needed in
order to arrive at the settlement rates. As the swap is a representation of the
interest rate differential between the two currencies quoted, as long as the
“near” and “far” sides of the swap quotation preserve this differential, it
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7 · Foreign Exchange
does not generally make a significant difference which exact spot rate is used
as a base for adding or subtracting the swap points. The rate must, however,
generally be a current rate. This is discussed further below: see “Historic rate
rollovers” and “Discounting future foreign exchange risk.”
Example 7.15
Spot USD/DEM:
31-day DEM interest rate:
31-day USD interest rate:
31-day forward swap:
1.6874 / 1.6879
3.0%
5.0%
30 / 28
Our bank’s dealer expects USD interest rates to rise. He therefore asks another
bank for its price, which is quoted as 30 / 28. Our dealer buys and sells USD 10
million at a swap price of 30 (that is, – 0.0030). The spot rate is set at 1.6876 and
the forward rate at 1.6846. The cashflows are therefore:
Spot
buy USD 10,000,000
sell DEM 16,876,000
31 days forward
sell USD 10,000,000
buy DEM 16,846,000
Immediately after dealing, USD rates in fact fall rather than rise, but DEM rates also
fall, as follows:
Spot USD/DEM:
31-day DEM interest rate:
31-day USD interest rate:
31-day forward swap:
1.6874 / 1.6879
2.5%
4.75%
34 / 32
Our dealer now asks another counterparty for a price, is quoted 34 / 32, and deals
to close out his position. Thus he now sells and buys USD at a swap price of 32
(that is, – 0.0032). The spot rate is set at 1.6876 again and the forward rate at
1.6844. The new cashflows are:
Spot
sell USD 10,000,000
buy DEM 16,876,000
31 days forward
buy USD 10,000,000
sell DEM 16,844,000
The net result is a profit of DEM 2,000, 31 days forward. The dealer has made a
profit because the interest differential between DEM and USD has widened from
2.0% to 2.25%, even though it did not widen in the way he expected.
In general:
A forward dealer expecting the interest rate differential to move in
favour of the base currency (for example, base currency interest rates rise
or variable currency interest rates fall) will “buy and sell” the base currency. This is equivalent to borrowing the base currency and depositing
in the variable currency.
Key Point
And vice versa
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Part 3 · Foreign Exchange
Historic rate rollovers
We have mentioned above that the settlement rates (spot and forward) for a
forward swap deal must generally be based on a current market spot rate. This
is because many central banks require that banks under their supervision use
only current rates. Example 7.16 illustrates why a corporate customer might
wish to use a historic rate rather than a current rate, and the effect.
Example 7.16
In June, a German company sells USD 10 million forward outright for value
15 August against DEM, at a forward outright rate of 1.5250. This deal is done to
convert money the company expects to receive from export sales. On 13 August,
the company realizes that it will not receive the money until a month later. It therefore rolls over the foreign exchange cover by using a forward swap – buying USD
spot and selling one month forward.
On 13 August, the exchange rates are as follows:
Spot USD/DEM:
31-day forward swap:
1.6874 / 79
30 / 28
The company therefore buys and sells USD at 1.6876 (spot) and 1.6876 – 0.0030 =
1.6846 (forward).
The company’s cashflows will then be:
15 August
sell USD 1,000,000
buy DEM 1,525,000
buy USD 1,000,000
sell DEM 1,687,600
Net:
sell DEM
162,600
15 September
sell USD
buy DEM
sell USD
buy DEM
1,000,000
1,684,600
1,000,000
1,684,600
The overall net result is that the company sells USD 1 million against DEM
1,522,000 (= DEM 1,684,600 – DEM 162,600) – an all-in rate of 1.5220 which is
effectively the original rate dealt of 1.5250 adjusted by the swap price of 30 points.
The company may however have a cashflow problem on 15 August, because there
is a cash outflow of DEM 162,600 then but no inflow. The company might therefore
prefer to request the bank to base the swap on the “historic” rate of 1.5250 – dealing instead at 1.5250 spot and 1.5220 forward.
The cashflows would then be:
15 August
sell USD 1,000,000
buy DEM 1,525,000
buy USD 1,000,000
sell DEM 1,525,000
Net:
15 September
sell USD
buy DEM
sell USD
buy DEM
1,000,000
1,522,000
1,000,000
1,522,000
The overall net result is the same as before, but there is no cashflow problem.
Underlying this arrangement, however, is an effective loan from the bank to the com-
164
7 · Foreign Exchange
pany of DEM 162,600 for 31 days. If the bank is, exceptionally, prepared to base the
swap on a historic rate, it needs to charge the company interest on this hidden loan.
This interest would normally be incorporated into a less favourable swap price.
The reason many central banks discourage historic rate rollovers is that they
may help a bank’s customer to conceal foreign exchange losses. If a customer has taken a speculative position which has made a loss, a historic rate
rollover enables it to roll the loss over to a later date rather than realize it.
Covered interest arbitrage
The link between interest rates and forward swaps allows banks and others
to take advantage of different opportunities in different markets. This can be
seen in either of two ways. First, suppose that a bank needs to fund itself in
one currency but can borrow relatively cheaply in another. It can choose
deliberately to borrow in the second currency and use a forward swap to
convert the borrowing to the first currency. The reason for doing this would
be that the resulting all-in cost of borrowing is slightly less than the cost of
borrowing the first currency directly.
Second, even if the bank does not need to borrow, it can still borrow in
the second currency, use a forward swap to convert the borrowing to the first
currency and then make a deposit directly in the first currency. The reason
for doing this would be that a profit can be locked in because the swap price
is slightly out of line with the interest rates.
Taking advantage of such a strategy is known as “covered interest arbitrage”.
Example 7.17
USD/DEM
spot:
3-month swap:
1.4810 / 1.4815
116 / 111
USD
DEM
3-month interest rates:
3-month interest rates:
7.43% / 7.56%
4.50% / 4.62%
Suppose that the 3-month period is 92 days and the bank needs to borrow DEM
10 million. It deals on rates quoted to it as above by another bank.
(a) Bank borrows USD 6,749,915.63 for 92 days from spot at 7.56%.
(b) At the end of 92 days, bank repays principal plus interest calculated as:
principal USD 6,749,915.63 plus interest USD 6,749, 915.63 × 0.0756 ×
92
360
= USD 6,880,324.00
(c) Bank “sells and buys” USD against DEM at a swap price of 111, based on a
spot of 1.4815:
Bank sells USD 6,749,915.63 / buys DEM 10,000,000.00 spot at 1.4815
Bank buys USD 6,880,324.00 / sells DEM 10,116,828.41 3 months forward at
1.4704
The net USD flows balance to zero.
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Part 3 · Foreign Exchange
The effective cost of borrowing is therefore interest of DEM 116,828.41 on a principal sum of DEM 10,000,000 for 92 days:
116,828.41 360
×
= 4.57%
10,000,000 92
The net effect is thus a DEM 10 million borrowing at 4.57% – 5 basis points
cheaper than the 4.62% at which the bank could borrow directly.
If the bank is in fact not looking for funds, but is able to deposit DEM at higher than
4.57%, it can instead “round trip”, locking in a profit.
Three points to notice in Example 7.17 are:
1. The example assumes that we are not the bank quoting the price; we are
taking another bank’s rates to borrow at 7.56 percent and swap at 111 points.
If we were able to trade on our own prices, the result would be even better.
2. When a swap is dealt, the amount of the deal (e.g. USD 6,749,915.63) is
usually the same at both ends of the deal, spot and forward. In the example above, the amounts are mismatched, with USD 6,880,324.00 at the far
end in order to match the cashflows exactly with the underlying flows
arising from the borrowing. It is generally acceptable in the market to use
mismatched amounts in this way as long as the mismatch is not great.
3. When dealing on a forward swap rather than a forward outright, it is the
swap price that is dealt rather than the spot price; the spot price is needed
only for settlement. The spot dealer is not involved and the spot spread is
not involved. In general therefore, the spot and forward settlement prices
could be 1.4815 and 1.4704 (as in Example 7.17) or 1.4810 and 1.4699
or something between. The spot rate must be a current market rate and
the difference between the spot and forward settlement prices must be the
correct swap price of 111 points. Conventionally, an approximate midprice is taken for the spot.
However, in Example 7.17, because the amounts are mismatched, it is
usual to use for the whole deal, whichever side of the spot price would normally be used for the mismatch amount. The size of the mismatch in this
example is a forward sale by the quoting bank of USD 130,408.37 (=
6,880,324.00 – 6,749,915.63). The quoting bank will wish to deal on the
right for this, based on a spot of 1.4815. This is therefore usually the spot rate
used for the deal. Although this approach is common, it does not in fact necessarily benefit the quoting bank. In Example 7.17, for instance, the quoting
bank is actually slightly worse off using a spot of 1.4815 and would instead
benefit from using 1.4810. In general, this depends on which of the two currencies’ interest rates is higher; the effect is in any case generally not great.
The formula we saw earlier for calculating a forward outright from interest
rates was:
forward swap = spot ×
166
(1 + variable currency interest rate × days
year)
(1 + base currency interest rate × days
year)
7 · Foreign Exchange
This can be turned round to give the result of the covered interest arbitrage
from the swap price:
Covered interest arbitrage
Calculation
summary
Creating the variable currency interest rate:
variable currency rate =
variable year
– 1] ×
[(1 + base currency rate × basedaysyear) × outright
spot
days
or
Creating the base currency interest rate:
base currency rate =
days
spot
base year
×
–1 ×
[(1 + variable currency rate × variable
year ) outright ]
days
Example 7.18
Using the same data as in Example 7.17, we have:
variable currency interest rate created
=
[(
1 + 7.56% ×
)
]
92
1.4704
360
×
–1 ×
360
1.4815
92
= 4.57%
.0756 ENTER 92 x 360 ÷ 1 + 1.4704 x 1.4815 ÷ 1 – 360 x 92 ÷
CROSS-RATE FORWARDS
Outrights
A forward cross-rate is a forward exchange rate between two currencies
other than the US dollar. These are calculated in a similar way to spot crossrates. To calculate a forward outright cross-rate between two indirect rates,
divide opposite sides of the forward rates against the US dollar.
Example 7.19
Spot USD/MYR:
6-month swap:
6-month outright:
2.4782 /
92
90 /
95
2.4872 / 2.4887
Spot USD/DEM:
6-month swap:
6-month outright:
1.6874 /
79
155 /
150
1.6719 / 1.6729
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Part 3 · Foreign Exchange
Therefore 6-month DEM/MYR is:
2.4872
= 1.4868: how the quoting bank buys DEM, sells MYR
1.6729
2.4887
= 1.4885: how the quoting bank sells DEM, buys MYR
1.6719
The forward outright cross-rate is therefore 1.4868 / 1.4885.
To calculate a forward outright cross-rate between two direct rates, again
divide opposite sides of the forward rates against the US dollar. Similarly, to
calculate a forward outright cross-rate between one direct rate and one indirect rate, multiply the same sides.
Example 7.20
Spot GBP/USD:
1-month swap:
1-month outright:
1.6166 /
71
14 /
9
1.6152 / 1.6162
Spot AUD/USD:
1-month swap:
1-month outright:
0.7834 /
39
60 /
55
0.7774 / 0.7784
Therefore 1-month GBP/AUD is:
1.6152
= 2.0750: how the quoting bank buys GBP, sells AUD
0.7784
1.6162
= 2.0790: how the quoting bank sells GBP, buys AUD
0.7774
The forward outright cross-rate is therefore 2.0750 / 2.0790.
Swaps
To calculate cross-rate forward swaps, the process above must be taken a
step further:
1. calculate the spot cross-rate
2. calculate the two individual forward outrights
3. from (2) calculate the forward outright cross-rate
4. from (1) and (3) calculate the cross-rate swap
Example 7.21
Using the same details as in Example 7.19, the DEM/MYR cross-rate swap can be
calculated as follows:
From Example 7.19, the forward outright rate is:
From Example 7.2, the spot rate is:
Therefore the forward swap is (outright – spot):
That is, 186 / 193.
168
1.4868 / 1.4885
1.4682 / 1.4692
0.0186 / 0.0193
7 · Foreign Exchange
SHORT DATES
Value dates earlier than one month are referred to as “short dates”. There
are certain “regular” dates usually quoted, and the terminology used is the
same as in the deposit market, as follows:
Overnight A deposit or foreign exchange swap from today until
“tomorrow.”
Terminology
Tom-next A deposit or foreign exchange swap from “tomorrow” to the
“next” day (spot).
Spot-next A deposit or foreign exchange swap from spot until the “next”
day.
Spot-a-week A deposit or foreign exchange swap from spot until a week
later.
Tomorrow means “the next working day after today” and next means “the
next working day following.”
When referring to outright deals rather than swaps, one refers to value
today, value tomorrow, value spot-next, value a week over spot.
In considering swaps and outright forwards for short dates later than the
spot date, exactly the same rules apply as in calculating longer dates.
However, confusion can arise in considering the prices for dates earlier than
spot – that is, value today and tomorrow. The rules are still the same in that
the bank buys the base currency on the far date on the left and sells the base
currency on the far date on the right. In other words, the bank always “sells
and buys” (in that order) the base currency on the left and “buys and sells”
the base currency on the right – regardless of whether it is before or after
spot. The confusion can arise because the spot value date – effectively the
baseline date for calculation of the outright rate – is the near date when calculating most forward prices. For value today and tomorrow, the spot date
becomes the far date and the outright date is the near date.
Example 7.22
Spot USD/DEM: 1.5505 / 10
Overnight swap:
1 / k
g / s
Tom-next swap:
1-week swap:
7 /
5
(i) Suppose a customer wishes to buy DEM for outright value one week after spot.
The bank spot dealer sells DEM for value spot on the left at 1.5505. The bank
forward dealer sells DEM for value on the “far” date ( = one week after spot) also
on the left at a swap difference of 7 points. Therefore the bank sells DEM out-
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right one week after spot at 1.5505 – 0.0007 = 1.5498. The other side of the one
week outright price is 1.5510 – 0.0005 = 1.5505.
(ii) Suppose the customer wishes to buy DEM for outright value tomorrow. This is
equivalent to buying DEM for value spot and, at the time, undertaking a swap to
buy DEM for value tomorrow and sell DEM back for value spot.
Again, the bank spot dealer buys USD for value spot on the left at 1.5505.
However, the bank forward dealer sells USD for value on the “far” date ( = spot
this time) on the right at a swap difference of s point. Furthermore (because DEM
interest rates are lower than USD rates) the USD is at a discount to the DEM: the
“bigger number” g is on the left. The USD is therefore worth less on the “far”
date and more on the “near” date. The swap difference is therefore added to the
spot rate to give an outright value tomorrow price of 1.5505 + s = 1.550525. The
other side of the value tomorrow outright price is 1.5510 + g = 1.55105.
A simple rule to remember for the calculation of dates earlier than spot is
“reverse the swap points and proceed exactly as for a forward later than
spot.” In Example 7.22, this would mean reversing g / s to s / g. The outright value tomorrow price is then (1.5505 + s) / (1.5510 + g), obtained by
adding the swap points to the spot rate because the “bigger” swap number is
now on the right. However, it is important always to remember to make this
reversal in your head only! Never actually quote the price in reverse!
“Overnight” prices are the only regular swap prices not involving the spot
value date. To calculate an outright value today price, it is therefore necessary to combine the “overnight” price with the “tom-next” price:
(iii) Suppose the customer wishes to buy DEM for outright value today. This is
equivalent to three separate transactions: buying DEM for value spot, undertaking a swap to buy DEM for value tomorrow and sell DEM back for value
spot (“tom-next”) and undertaking another swap to buy DEM for value today
and sell DEM back for value tomorrow (“overnight”). The price is therefore
1.5505 + s + k = 1.5506.
The “rules” can be thought of in terms of premiums and discounts, which
apply in the same way as in forwards after spot. The swaps in the previous
example show a USD discount because DEM interest rates are lower than USD
interest rates. Consequently, if the customer buys DEM value today and not
value spot, he/she will receive the currency with the lower interest rate two
days early. The extra point which he/she receives from the bank reflects this.
Deals cannot always be done for value today. For example, when London
and European markets are open, the Japanese banks have already closed
their books for today, so deals in yen can only be done for value tomorrow.
Similarly, in London, most European currencies can only be dealt early in the
morning for value today, because of the time difference and the mechanical
difficulties of ensuring good value. Even the market for value “tomorrow”
generally closes during the morning.
Some further examples follow. “Overnight,” “tom-next,” “spot-next” and
“spot-a-week” are often abbreviated as O/N, T/N, S/N and S/W respectively.
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7 · Foreign Exchange
Example 7.23
GBP/USD spot rate:
O/N:
T/N:
S/N:
1.5103
s
s
s
/
/
/
/
13
g
g
g
The bank’s customers can make purchases and sales as follows:
Value S/N:
Outright purchase of USD and sale of GBP:
1.5103 + 0.000025 = 1.510325
Outright sale of USD and purchase of GBP:
1.5113 + 0.00005 = 1.51135
Value tomorrow: Outright purchase of USD and sale of GBP:
1.5103 – 0.00005 = 1.51025
Outright sale of USD and purchase of GBP:
1.5113 – 0.000025 = 1.511275
Value today:
Outright purchase of USD and sale of GBP:
1.5103 – 0.0001 = 1.5102
Outright sale of USD and purchase of GBP:
1.5113 – 0.00005 = 1.51125
CALCULATION SUMMARY
It may be helpful to collect together here various “rules” which apply to calculating forwards:
Key Points
1. The currency with higher interest rates ( = the currency at a “discount”)
is worth less in the future.
The currency with lower interest rates ( = the currency at a “premium”)
is worth more in the future.
2. The bank quoting the price buys the base currency / sells the variable
currency on the far date on the left.
The bank quoting the price sells the base currency / buys the variable
currency on the far date on the right.
For outright forwards later than spot
3. The right swap price is added to (or subtracted from) the right
spot price.
The left swap price is added to (or subtracted from) the left spot price.
▼
4. If the swap price is larger on the right than the left, add it to the
spot price.
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If the swap price is larger on the left than the right, subtract it from
the spot price.
For outright deals earlier than spot
5. Calculate as if the swap price were reversed and then follow (3) and (4).
In general
6. Of the two prices available, the customer gets the worse one. Thus
if the swap price is 3 / 2 and the customer knows that the points are
“in his favour” (the outright will be better than the spot), the price
will be 2. If he knows that the points are “against him” (the outright will be worse than the spot), the price will be 3.
7. The effect of combining the swap points with the spot price will
always be to widen the spread, never to narrow it.
VALUE DATES
Swap rates are normally quoted for “regular” dates – for example 1, 2, 3, 6
and 12 months forward. They are quoted over the spot date. This means that
the one-month swap rates are calculated for one calendar month after the
present spot date. If the current spot date is 21 April, the one month forward
date will be 21 May. If the forward delivery date falls on a weekend or holiday, the value date becomes the next working day. No adjustment in the
forward value date is made for any weekends or public holiday between the
spot date and the forward delivery date.
An exception to these rules is when the spot value date is at or close to the
end of the month. If the spot value date is the last working day of a month,
the forward value date is the last working day of the corresponding forward
month; if necessary, the forward value date is brought back to the nearest
previous business day in order to stay in the same calendar month, rather
than moved forward to the beginning of the next month. This is referred to
as dealing “end/end.”
Example 7.24
Ordinary Run
Dealing date:
Spot date:
1 month:
2 months:
3 months:
4 months:
172
Friday 14 April
Tuesday 18 April (2 working days forward)
Thursday 18 May
Monday 19 June (18 June is a Sunday)
Tuesday 18 July
Friday 18 August
7 · Foreign Exchange
End/End
Dealing date:
Spot date:
1 month:
2 months:
etc.
Wednesday 26 June
Friday 28 June (last working day of June)
Wednesday 31 July (last working day of July)
Friday 30 August (last working day of August)
Similarly, even if the spot value date is earlier than the last working day of
the month, but the forward value date would fall on a non-working day, this
is still brought back rather than moved later, if necessary to keep it in the
appropriate month.
Example 7.25
Dealing date:
Spot date:
1 month:
2 months:
etc.
Monday 28 August
Wednesday 30 August (not the last working day)
Friday 29 September (30 September is a Saturday)
Monday 30 October
If a bank deals in any month that is not a regularly quoted date, for example,
for four or five months’ maturity, this is called an “in-between” month
because it is between the regular dates. A forward deal may in fact be
arranged for value on any day which is a working day in both currencies.
Dates which do not fit in with calendar month dates are called “broken
dates” or “odd dates.” The forward swap points are generally calculated by
straightline interpolation between the nearest whole month dates either side.
FORWARD-FORWARDS
A forward-forward swap is a swap deal between two forward dates rather
than from spot to a forward date – for example, to sell US dollars one month
forward and buy them back in three months’ time. In this case, the swap is
for the two-month period between the one-month date and the three-month
date. A company might undertake such a swap because it has previously
bought dollars forward but wishes now to defer the transaction by a further
two months, as it will not need the dollars as soon as it thought.
From the bank’s point of view, a forward-forward swap can be seen as
two separate swaps, each based on spot.
Example 7.26
USD/DEM spot rate:
1-month swap:
3-month swap:
1.5325 / 35
65 / 61
160 / 155
If our bank’s counterparty wishes to sell USD one month forward, and buy them
three months forward, this is the same as undertaking one swap to buy USD spot
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and sell USD one month forward, and another swap to sell USD spot and buy USD
three months forward.
As swaps are always quoted as how the quoting bank buys the base currency forward
on the left, and sells the base currency forward on the right, the counterparty can “buy
and sell” USD “spot against one month” at a swap price of -65, with settlement rates
of spot and (spot – 0.0065). He can “sell and buy” USD “spot against three months” at
a swap price of -155 with settlement rates of spot and (spot – 0.0155). He can therefore do both simultaneously – “sell and buy” USD “one month against three months” –
at settlement rates of (spot – 0.0065) and (spot – 0.0155), which implies a difference
between the two forward prices of (-155) – (-65) = -90 points.
Conversely, the counterparty can “buy and sell” USD “one month against three
months” at a swap price of (-160) – (-61) = -99 points. The two-way price is therefore -99 / -90, quoted as usual without the “-” signs, as 99 / 90.
As with a swap from spot to a forward date, the two settlement prices in a forward-forward must be based on a current market rate. In Example 7.26, using
the middle spot rate, the settlement rates could be 1.5265 (= 1.5330 – 0.0065)
for 1 month forward and 1.5175 (= 1.5330 – 0.0155) for 3 months forward.
These settlement rates would enable our forward dealer to cover his position exactly with another bank. We could, for example, ask another bank for
a 1-month swap price to cover the first leg of the forward-forward. Assuming
prices have not moved, we could deal at -65 points with settlement rates of
1.5330 (spot) and 1.5265 (1 month). We could then cover the second leg
with a 3-month swap at another bank’s price of -155, with settlement rates
of 1.5330 (spot) and 1.5175 (3 months). The spot settlements would offset
each other and the forward settlements would exactly offset the settlements
with our own counterparty.
In practice, however, forward dealers often base the settlement rate for the
first leg on a middle rate for spot and a middle rate for the near forward date.
In the example above, this would give a settlement rate of 1.5330 (middle) –
0.0063 (middle) = 1.5267. The settlement rate for the second leg would then be
1.5267 – 0.0090 = 1.5177. The difference between the two settlement rates is
still the -90 points agreed, but the settlement rates are slightly different.
The calculation rule to create the forward-forward price after spot is as follows:
Calculation
summary
Forward-forward price after spot
Left side = (left side of far-date swap) – (right side of near-date swap)
Right side = (right side of far-date swap) – (left side of near-date swap)
Note that the bid-offer spread of the resulting price is the sum of the two
separate bid-offer spreads.
Care needs to be taken with swaps from before spot to after spot:
Example 7.27
USD/DEM spot rate
T/N swap:
3-month swap:
174
1.5325 / 35
3 /
2
160 / 155
7 · Foreign Exchange
If a counterparty requests a price to sell and buy USD tomorrow against 3 months
after spot, this can be seen as a price to sell tomorrow and buy spot at (-2) points
with settlement rates of (spot + 0.0002) and spot, and a price to sell spot and buy 3
months later at (-155) points with settlement rates of spot and (spot – 0.0155). The
total price is therefore the difference between (spot – 0.0155) and (spot + 0.0002),
which is (-155) – (+2) = -157. The other side of the price is (-160) – (+3) = -163. The
two-sided price is therefore 163 / 157.
TIME OPTIONS
When a bank makes a forward outright deal with a company, it will quote a
rate for a fixed date, which means the company must deliver one currency
and receive another on that date.
If the company has a commitment in the future but does not know the
exact delivery date, it has an alternative means of covering this exposure in
the traditional foreign exchange market, using “time options.” These allow
the company to deal now, but to choose the maturity date later, within a
specified period. Delivery must take place at some point during that period,
however, for the amount and rate agreed.
It is important not to confuse “time options” in this sense with “currency
options” which are covered later. “Currency options” entail the up-front
payments of an “insurance premium”, in return for which the customer has
the right to choose whether or not to deal at all.
In pricing a time option, the bank will always assume that the company
will take delivery of the currency at the worst possible time for the bank.
Therefore the company will always be charged the worst possible forward
rate within the period of the time option.
Example 7.28
USD/DEM
Spot rate:
6-month swap:
7-month swap
1.7950 / 60
485 / 475
560 / 550
If a customer wants to buy DEM with an option for delivery between six and seven
months, the bank will assume in pricing the option that delivery will be after seven
months (560 points against the customer). However, if the customer wants to sell
DEM with an option for delivery between six and seven months, the bank will
assume that delivery will be after six months (only 475 points in the customer’s
favour). The time option price will therefore be (1.7950 – 0.0560) / (1.7960 – 0.0475)
= 1.7390 / 1.7485.
The advantage of a time option to a company is its flexibility. The company
can lock in a fixed exchange rate at which it knows it can deal. There is no
exposure to interest rate changes which would affect it if commitments were
covered with a forward outright which subsequently needed to be adjusted by
means of forward swaps. The disadvantage is the cost, given the wide bid/offer
spread involved, particularly if the time period of the option is wide.
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Key Point
A time option price is the best for the bank / worst for the customer over
the time option period
LONG-DATED FORWARDS
The formula we have already seen for a forward outright less than one year is:
1 + variable interest rate × days
(
year)
Forward outright = spot ×
days
(1 + base interest rate × year)
This is derived from the fact that the interest on a Eurocurrency deposit or
loan is paid on a simple basis. For deposits and loans over one year, the
interest must be compounded. The formula for a forward over one year will
be, correspondingly:
where N is the number of years, and the interest rates are quoted on the basis
of a true calendar year rather than a 360-day year. This theoretical formula
Forward outright = spot ×
(1 + variable interest rate)N
(1 + base interest rate)N
is not precise in practice for two reasons. First, this compounding does not
take account of reinvestment risk. This problem could be overcome by using
zero-coupon yields for the interest rates. More importantly, the market in
long-dated forwards is not very liquid and spreads are very wide. The prices
available in practice therefore depend partly on banks’ individual positions
and hence their interest in quoting a price.
Calculation
summary
For long-dated forwards
Forward outright = spot ×
(1 + variable interest rate)N
(1 + base interest rate)N
SYNTHETIC AGREEMENTS FOR FORWARD EXCHANGE (SAFEs)
A SAFE is essentially a form of off-balance sheet forward-forward foreign
exchange swap. There are two versions of a SAFE – an FXA and an ERA.
An FXA (foreign exchange agreement) exactly replicates the economic
effect of a forward-forward in the cash market which is reversed at the first
forward date to take a profit or loss. A price for an FXA is quoted in the
same way as a forward-forward, and is dealt in the same way. A forwardforward swap results in two cash settlements, each for the whole notional
amount of the deal. An FXA, however, is settled in a manner analogous to
the way an FRA is settled. On the nearer of the two forward dates, a settle176
7 · Foreign Exchange
ment amount is paid from one party to the other to reflect the movement in
rates between dealing and settlement. The settlement amount is calculated
using agreed settlement rates, such as the BBA (British Bankers’ Association)
settlement rates published on Reuters. The settlement formula ensures that
the result is the same as the profit or loss would be with a cash forwardforward. To do so, the formula takes account of the movement in the spot
rate from dealing to settlement, as well as the movement in the forward swap
points. This is because although a forward dealer takes a position on the
basis of his expectations of swap movements his profit / loss is also affected
to some extent by spot rate movements. The reason for this is discussed in
Discounting Future Foreign Exchange Risk later. As with an FRA, the settlement formula involves an element of discounting, because the settlement is
made at the beginning of the forward-forward period.
An ERA (exchange rate agreement) price is exactly the same as an FXA
price, and allows for a discounted settlement to be made at the beginning of
the forward-forward period in the same way as an FXA. The ERA settlement, however, deliberately takes no account of the movement in the spot
rate, and the settlement formula is correspondingly simpler. The two instruments can therefore be compared as follows:
• An FXA replicates exactly the effect of a cash forward-forward. In a
Key Point
trading strategy that requires a forward-forward therefore, an FXA is
an alternative.
• An ERA may be used to trade movements in forward swap prices when
the trader specifically wishes the result to be unaffected by movements
in the spot rate. This does not exactly replicate a forward-forward.
Advantages of SAFEs
The advantages of a SAFE lie in the problems which arise on credit lines and
balance sheet utilization. In the absence of an appropriate netting agreement,
when a bank deals forward-forward its credit lines to and from the counterparty are generally utilized to the extent of twice the notional credit amount
applied to the deal – once for each leg of the forward-forward. Between dealing date and the first settlement date, however, the risk may be far less than
this, because the two legs of the deal largely offset each other. The credit
exposure allocated to a SAFE, as a contract for differences, will be far less.
The capital utilization requirements are similarly reduced. Rather than
having two deals on the balance sheet, there are none.
A further advantage of an ERA arises if a forward trader wishes to trade
the forward swap points without needing to hedge the effect of potential spot
rate movements (although this does not avoid the effect that a significant
spot rate movement may have on a swap price itself).
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Part 3 · Foreign Exchange
FXAs (foreign exchange agreements)
In order to understand the FXA settlement formula, it is helpful to look at
the actual cashflows which would arise in a cash forward-forward deal
which is reversed two working days before the first forward date. It is then
possible to build up the transactions and cashflows implied in the FXA settlement formula.
Example 7.29
Our dealer sells and buys USD10 million, 1 month against 3 months, when rates
are as follows:
USD/DEM spot:
1-month swap (31 days):
3-month swap (92 days):
1.7400
50 / 51
153 / 156
We ask for a price from another bank and deal at 106 points ( = 156 – 50). The settlement rates will be 1.7450 ( = 1.7400 + 0.0050) and 1.7556 ( = 1.7400 + 0.0156).
Our cashflows will be as follows:
1 month
– USD 10,000,000
+ DEM 17,450,000
3 months
+ USD 10,000,000
– DEM 17,556,000
After 1 month, our dealer reverses the position by buying and selling USD10 million
spot against 2 months. Rates are now as follows and he deals on another bank’s
prices at 1.7500 and 1.7618:
USD/DEM spot:
2-month swap (61 days):
2-month DEM interest rate:
1.7500
118 / 120
5.3%
Our cashflows are now as follows:
1 month
– USD 10,000,000
+ DEM 17,450,000
+ USD 10,000,000
– DEM 17,500,000
Net: – DEM
50,000
3 months
+ USD 10,000,000
– DEM 17,556,000
– USD 10,000,000
+ DEM 17,618,000
+ DEM
62,000
Having reached the 1-month date and ascertained these cashflows, we are able
effectively to move the cashflow of + DEM 62,000 from 3 months to now, by borrowing the present value of that amount. That is, we can borrow the amount
DEM 62,000
61
–
(1 + 0.053 × 360
)
= DEM 61,448 for 2 months. If we do this, our cashflows become:
1 month
– USD 10,000,000
+ DEM 17,450,000
+ USD 10,000,000
– DEM 17,500,000
+ DEM
61,448
Net: + DEM
11,448
3 months
+ USD 10,000,000
– DEM 17,556,000
– USD 10,000,000
+ DEM 17,618,000
– DEM
62,000
–
After 1 month, we can therefore crystallize the result of the deals as +DEM 11,448.
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7 · Foreign Exchange
In Example 7.29, the amount of + DEM 62,000 can be seen as arising from:
10 million × (1.7618 – 1.7556)
= – 10 million × [(1.7450 – 1.7500) + (0.0106 – 0.0118)]
Therefore the amount + DEM 61,448 can be seen as:
–
10 million × [(1.7450 – 1.7500) + (0.0106 – 0.0118)]
61
(1 + 5.3% × 360
)
Similarly, the amount of – DEM 50,000 can be seen as arising from:
+ 10 million × (1.7450 – 1.7500)
The net result of + DEM 11,448 therefore comes from:
–10 million ×
[
(1.7450 – 1.7500) + (0.0106 – 0.0118)
61
(1 + 5.3% × 360
)
]
+ 10 million × [1.7450 – 1.7500]
In an FXA, we achieve exactly the same result as in Example 7.29, but
without any of the transactions shown. Instead, we agree with a counterparty to make a settlement based on the same settlement formula, which can
be expressed as:
The FXA settlement amount
A2 ×
[
]
(OER – SSR) + (CFS – SFS)
– A1 × [OER – SSR]
(1 + L × days
year
)
Calculation
summary
paid by the “seller” to the “buyer” of the FXA (or vice versa if it is a
negative amount), where the “buyer” is the party which buys the base
currency on the first date and sells it on the second date.
and where:
A1
A2
= the base currency amount transacted at the beginning of the swap.
= the base currency amount transacted at the end of the swap.
(A1 and A2 may be the same amount, as in the above example, but do not
need to be.)
OER = the outright exchange rate, when the FXA is transacted, to the
beginning of the swap.
SSR = the settlement spot rate two working days before the swap period.
CFS = the contract forward spread – that is, the swap price agreed when
the FXA is transacted.
SFS = the settlement forward spread – that is, the swap price used for settlement two working days before the swap period.
L
= variable currency LIBOR for the swap period, two working days
before the swap period.
days = the number of days in the swap period.
year = the year basis for the variable currency.
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Part 3 · Foreign Exchange
Example 7.30
Based on the same data as in Example 7.29, we have:
A1
A2
OER
SSR
CFS
SFS
L
days
year
=
=
=
=
=
=
=
=
=
10,000,000
10,000,000
1.7450 (= 1.7400 + 0.0050)
1.7500
0.0106 (= 0.0156 – 0.0050)
0.0119
0.053
61
360
The settlement amount is therefore:
10,000,000 ×
[
(1.7450 – 1.7500) + (0.0106 – 0.0119)
(1 + 0.053 × )
61
360
]
–10,000,000 × [1.7450 – 1.7500]
= –12,439.26
That is, DEM12,439.26 is paid to the seller of the FXA.
1.745 ENTER 1.75 – .0106 + .0119 .053 ENTER 61 × 30 ÷ 1 + ÷ 10,000,000 ×
1.745 ENTER 1.75 – 10,000,000 × -
Note that in the case of the FXA, the settlement is made on the basis of a published settlement forward spread which should be a mid-rate (0.0119 rather
than 0.0118, for example) – hence the slightly improved result for our dealer.
To see that this is a “fair” settlement, consider that the counterparty (the
buyer of the FXA) can cover its position at no risk by dealing as follows:
• At the outset, sell and buy USD10 million one month against three months.
• After one month, buy and sell USD10 million spot against two months.
• Also after one month, borrow DEM61,448 for two months at LIBOR (5.3%).
ERAs (exchange rate agreements)
An FXA exactly replicates a forward-forward swap in that the final settlement is economically the equivalent of transacting a forward-forward swap –
with either equal or unequal amounts at each end of the swap. An FXA is
affected by changes in both spot and forward swap rates.
An ERA is similar but is only affected by changes in the swap rate. Thus
the settlement amount is simply the notional amount of the contract multiplied by the change in the swap rate. As the settlement is made at the
beginning of the swap period rather than at the end, it is discounted back to
180
7 · Foreign Exchange
a present value in the same way as an FRA settlement or an FXA settlement.
With the same notation as with an FXA, the settlement amount is therefore:
The ERA settlement amount
(
A × CFS – SFS
1 + L × days
year
)
Calculation
summary
In this case, only one notional amount A is involved. Again, the settlement
amount is paid to the buyer of the ERA if it is positive.
Example 7.31
Our dealer expects US interest rates to fall and, by selling an ERA for USD10
million, takes a speculative position. Rates are the same as in Example 7.30:
USD/DEM spot:
1-month swap:
3-month swap:
1.7400
50 / 51
153 / 156
After one month, the rates are as follows:
USD/DEM spot:
2-month settlement forward spread:
2-month DEM LIBOR:
1.7500
0.0119
5.3%
As before, we have:
A
CFS
SFS
L
days
year
=
=
=
=
=
=
10,000,000
0.0106 (= 0.0156 – 0.0050)
0.0119
0.053
61
360
The settlement amount is:
10,000,000 ×
(0.0106 – 0.0119)
61
(1 + 0.053 × 360
)
= –12,884.29
That is, DEM 12,884.29 is paid to our dealer as the seller of the ERA. Our dealer
has made a profit because the forward price has moved as he expected.
0.0106 ENTER .0119 – .053 ENTER 61 × 360 ÷ 1 + ÷ 10,000,000 ×
ARBITRAGING AND CREATING FRAs
In addition to using SAFEs for taking positions as an alternative to forwardforwards, FXAs can be used to arbitrage between FRAs in different currencies,
or to create synthetic FRAs. Because theoretical forward swap prices and FRAs
are both linked mathematically to the current Eurointerest rates, it should be
possible to round-trip between FRAs and forward-forwards at zero cost – or, if
181
Part 3 · Foreign Exchange
prices are out of line, to make an arbitrage profit. Because FXAs are economically equivalent to forward-forwards, this round-trip can be made using FRAs
and FXAs instead. Essentially, the following holds:
Key Point
Buy FRA in currency A = buy FRA in currency B
+ buy FXA in exchange rate A/B
In this way, it is possible to create an FRA in one currency – say a currency in
which FRAs are not finely priced – from an FRA in another currency. Similarly:
Key Point
Buy FRA in currency A + sell FRA in currency B
+ sell FXA in exchange rate A/B = 0
In this way, it is possible to arbitrage between FRAs in two currencies using
the FXA market, if prices are out of line.
Example 7.32 works through the details of how a SEK FRA can be created
from a USD FRA. In order to clarify all the underlying cashflows – which are
largely absorbed into one settlement figure when an FXA is used – the example uses cash forward-forwards instead of an FXA. We have then repeated
the example using an FXA. In both cases, we have used middle rates for simplicity and clarity, rather than separate bid and offer rates.
Example 7.32
Rate structure at the start:
Spot:
3 months (91 days):
6 months (182 days):
USD/SEK
6.0000
6.0598
6.1178
USD%
SEK%
6.00
6.00
10.00
10.00
The 3 v 6 USD FRA rate is:
[
(1 + 0.06 × 182
360) – 1
91
(1 + 0.06 × 360
)
]
×
360
= 5.91%
(182 – 91)
The theoretical 3 v 6 SEK FRA rate is:
[
(1 + 0.10 × 182
360) – 1
91
(1 + 0.10 × 360
)
]
×
360
= 9.753%
(182 – 91)
Outline structure
Assuming that it is not possible to obtain satisfactory FRA prices in SEK from a
bank, we will create a synthetic SEK FRA by combining a USD FRA with various
forward foreign exchange deals. This is structured as follows:
182
7 · Foreign Exchange
(i)
Assume a borrowing in USD for 3 months, starting in 3 months’ time. Arrange
now a USD FRA 3 v 6 on this USD borrowing
(ii) Convert the resulting fixed-cost USD borrowing to a fixed-cost SEK borrowing
by a forward-forward swap:
selling USD / buying SEK now for value in 3 months’ time
buying USD / selling SEK now for value in 6 months’ time
(iii) After 3 months, instead of the dollar borrowing which has been assumed, this
borrowing is synthesized from a 3-month SEK borrowing and more forward
deals. To achieve this, it is necessary after 3 months to:
(iv) Convert the SEK borrowing to a USD borrowing by:
buying USD / selling SEK for value spot
selling USD / buying SEK for value 3 months forward
Detailed structure
(i)
1,000,000
= USD 165,021.95 in 3 months’ time.
6.0598
This will achieve SEK 1,000,000 if it is converted forward now.
Assume a borrowing of USD
Arrange a 3 v 6 FRA at 5.91% on USD 165,021.95. Although the FRA settlement
will in fact be after 3 months on a discounted basis, the economic effect will be
as if we had borrowed at 5.91% for the period, with the following total repayment
at the end of 6 months (we can in fact achieve exactly this result by investing or
borrowing the FRA settlement amount from 3 months to 6 months at LIBOR):
(
USD 165,021.95 × 1 + 0.0591 ×
91
= USD 167,487.24
360
)
(ii) 3 months forward: sell USD 165,021.95 / buy SEK 1,000,000.00 (at 6.0598)
6 months forward: buy USD 167,487.24 / sell SEK 1,024,653.44 (at 6.1178)
After 3 months from the start, suppose the following new rate structure:
USD/SEK
7.0000
7.1223
Spot:
3 months (91 days):
(i)
USD%
SEK%
5.00
12.00
The discounted FRA settlement amount is
USD 165,021.95 × (0.0591 – 0.05) ×
91
(1 + 0.05 × 360
)
91
360
= USD 374.86
We borrow this settlement amount (which is to be paid by us because interest
rates have fallen) for 3 months at 5.00% to give an all-in settlement cost to be
paid at the end of:
USD 374.86 × (1+ 0.05 ×
91
360
) = USD 379.60
(iii) Borrow SEK (165,021.95 x 7.0000) = SEK 1,155,153.65 for 3 months
Total repayment after 3 months would be:
(
SEK 1,155,153.65 × 1 + 0.12 ×
91
= SEK 1,190,193.31
360
)
183
Part 3 · Foreign Exchange
(iv) Spot: sell SEK 1,155,153.65 / buy USD 165,021.95 (at 7.0000)
3 months forward: buy SEK 1,190,193.31 / sell USD 167,108.00 (at 7.1223)
Resulting cashflows
After 3 months:
SEK
+ 1,000,000.00
+ 1,155,153.65
– 1,155,153.65
+ 1,000,000.00
After 6 months:
– 1,024,653.44
– 1,190,193.31
+ 1,190,193.31
– 1,024,653.44
USD
– 165,021.95
(ii) First hedge
(iii) SEK loan
(iv) Second hedge
(i)
(ii)
(iii)
(iv)
+ 165,021.95
–
FRA settlement
First hedge
Loan repayment
Second hedge
–
379.60
+ 167,487.24
– 167,108.00
–
The resulting effective cost of borrowing the SEK 1,000,000 is:
The final step
24,653.44 360
×
= 9.753%, which is the theoretical SEK FRA cost.
1,000,000 91
So far, we have created a forward cash borrowing in SEK at 9.75%, rather than an
FRA. The final step is to remove the cash element, by subtracting from step (iii) in
the structure the originally intended notional principal cash amount of SEK
1,000,000. This reduces the amount in step (iii) to SEK 155,153.65. The repayment
on this amount is:
SEK 155,153.65 × (1 + 0.12 ×
91
360
) = SEK 159,859.98
This leaves the following cashflows:
SEK
After 3 months: + 1,000,000.00
+ 155,153.65
– 1,155,153.65
–
After 6 months:
– 1,024,653.44
– 159,859.98
+ 1,190,193.31
+
5,679.89
(ii) First hedge
(iii) SEK loan
(iv) Second hedge
USD
– 165,021.95
+ 165,021.95
–
(i) FRA settlement –
379.60
(ii) First hedge
+ 167,487.24
(iii) Loan repayment
(iv) Second hedge – 167,108.00
–
If we discount this resulting net inflow back three months at 12.00%, we have:
SEK 5,679.89 = SEK 5,513
91
(1 + 0.12 × 360
)
This is the same settlement amount as if we had been able to buy a SEK FRA at
9.753%:
SEK 1,000,000 × (0.12 – 0.09753) ×
91
(1 + 0.12 × 360
)
184
91
360
= SEK 5,513
7 · Foreign Exchange
In practice, because of the various bid/offer spreads involved, the effective
cost would be higher than this – although the spreads on the FX forward
deals are reduced slightly because they are swap deals rather than forward
outright deals, so that the bid/offer spread is not paid on the spot price as
well as on the forward swaps. The question would therefore be whether this
synthetic FRA rate is more attractive than a straightforward FRA in SEK.
Because an FXA replicates the effects of a cash forward-forward foreign
exchange deal, we can repeat the above example using an FXA.
Example 7.33
With the same data as in Example 7.32, we wish to create a synthetic SEK FRA
as follows:
buy USD FRA at 5.91% on USD 165,021.95
sell USD/SEK FXA at + 580 points (= 6.1178 – 6.0598)
With the same notation as in the previous section, we have:
A1
A2
OER
SSR
CFS
SFS
L
days
year
=
=
=
=
=
=
=
=
=
USD 165,021.95
USD 167,487.24
6.0598
7.0000
0.0580
0.1223 ( = 7.1223 – 7.0000)
0.12
91
360
The FXA settlement is then:
167,487.24 ×
[
(6.0598 – 7.0000) + (0.0580 – 0.1223)
(1 + 0.12 ×
91
360
)
]
–165,021.95 × [6.0598 – 7.0000]
= –8,134.23
That is, SEK 8,134.23 paid to us as the seller of the FXA.
The FRA settlement amount is:
165,021.95 × (0.05 – 0.0591) ×
91
(1 + 0.05 × 360
)
91
360
= –USD 374.86
That is, 374.86 paid by us as buyer of the FRA. This can be converted spot to SEK
2,624.02 (= 374.86 × 7.0000).
The net settlement received from the two deals is thus SEK 8,134.23 – SEK
2,624.02 = SEK 5,510.
Apart from rounding differences, this is the same result as in Example 7.32.
In the section Relationship with the Money Markets we gave the covered
interest arbitrage formula for creating one interest rate from another:
185
Part 3 · Foreign Exchange
variable currency interest rate created =
[(1 + base currency interest rate ×
days
base year
variable year
– 1] ×
) × outright
spot
days
This formula can be adapted for forward periods as follows:
Calculation
summary
Variable currency FRA rate =
outright to far date
variable year
days
1 + base currency FRA rate × year ×
–1 ×
outright to near date
days
[(
]
)
In the example above, this would give the SEK FRA rate created as:
91
6.1178
360
–1] ×
= 9.75%
) × 6.0598
[(1 + 0.0591 × 360
91
Expressing this for the base currency gives:
Calculation
summary
Base currency FRA rate =
outright to near date
base year
days
1 + base currency FRA rate × variable year ×
–1 ×
outright to far date
days
[(
]
)
In the same way, we can reverse the arbitrage process and create a forwardforward foreign exchange swap (or FXA) from two FRAs (or forward-forwards
or futures). Again, the formula given in the section Forward Swaps for a normal
foreign exchange swap can be adapted directly for forward periods:
Calculation
summary
Forward-forward swap =
outright to near date ×
– base currency FRA × days
(variable currency FRA × days
year
year )
days
1
+
base
currency
FRA
×
(
year)
DISCOUNTING FUTURE FOREIGN EXCHANGE RISK
We have suggested on several occasions that there is a risk for a forward foreign exchange position which arises out of potential spot exchange rate
movements rather than just the movements in the forward swap price.
Example 7.34
Our forward dealer sells and buys USD 1 million against NLG, 3 months against
6 months, at the following rates, because he expects the NLG’s forward discount
to increase (a fall in USD interest rates relative to NLG rates).
Spot:
3 months (90 days):
6 months (180 days):
186
USD/NLG
2.0000
2.0098
2.0172
USD%
NLG%
8.0
8.8
10.0
10.6
7 · Foreign Exchange
The cashflows arising from the deal are as follows:
90 days
– USD 1,000,000
+ NLG 2,009,800
180 days
+ USD 1,000,000
– NLG 2,017,200
Now consider an immediate move in rates to the following:
USD/NLG
2.1000
2.1103
2.1181
Spot:
3 months:
6 months:
USD%
NLG%
8.0
8.8
10.0
10.6
Even though interest rates have not moved, the NLG’s forward discount has
increased slightly, because the change in the spot rate from 2.0000 to 2.1000 has
“magnified” the forward points. The dealer therefore expects to have made a profit.
In fact, however, the bank as a whole has made a loss. Suppose that the deal is
now closed out at current rates. The cashflows become:
Spot
–
–
–
–
90 days
– USD 1,000,000
+ NLG 2,009,800
+ USD 1,000,000
– NLG 2,110,300
– NLG 100,500
180 days
+ USD 1,000,000
– NLG 2,017,200
– USD 1,000,000
+ NLG 2,118,100
+ NLG 100,900
The net effect appears to be a profit of NLG 400 (= NLG 100,900 – NLG 100,500).
However, the outflow of NLG 100,500 after 90 days must be financed for 3 months
before the inflow of NLG 100,900. The forward-forward rate for this financing is:
1 + 0.106 × 180
360
(
1 + 0.10 ×
90
360
)
–1 ×
360
= 10.9268%
(180 – 90)
The cost of funding is therefore:
NLG 100,500 × 10.9268% ×
90
360
= NLG 2,745
This financing cost is a real loss, which has arisen because of the spot rate movement. It is therefore possible for the dealer to make a profit by correctly
anticipating interest rate movements, but for this profit to be more than offset by
the spot rate movements.
The exposure – known as the forward “tail” – arises because of the time difference
between the cashflows. It is possible to compensate for this effect by hedging the
NPV of the original cashflows.
The NPV of the USD cashflows is:
USD 1,000,000 USD 1,000,000
+
= – USD 22,538
90
(1 + 0.08 × 360
) (1+ 0.088 × 180
360)
On an NPV basis, the dealer is therefore short of USD 22,538.
A possible hedge is therefore to buy USD 22,538 for value spot at the same time
as the original deal. The cashflows if the deal and the hedge were closed out would
then be:
187
Part 3 · Foreign Exchange
Spot
+ USD 22,538
– NLG 45,076
– USD 22,538
+ NLG 47,330
+ NLG 2,254
90 Days
– USD 1,000,000
+ NLG 2,009,800
+ USD 1,000,000
– NLG 2,110,300
– NLG
100,500
180 Days
+ USD 1,000,000
– NLG 2,017,200
– USD 1,000,000
+ NLG 2,118,100
+ NLG 100,900
It is possible to deposit the NLG 2,254 profit from spot until three months at 10%,
for total proceeds of:
NLG 2,254 × (1 + 0.10 ×
90
360
) = NLG 2,310
This gives a net cashflow after 3 months of:
NLG 2,310 – NLG 100,500 = – NLG 98,190
At the forward-forward NLG rate of 10.9268%, it is possible to fund this net NLG
98,190 from 3 months until 6 months for a total repayment of:
NLG 98,190 × (1 + 0.109268 ×
90
360
) = NLG 100,872
This amount is offset by the NLG 100,900 profit after 6 months (the difference is
due only to rounding).
Discounting in this way is effective because forward swap deals are equivalent to deposits and loans in the two currencies. Clearly deposits and loans
in the domestic currency (NLG in this case) are unaffected by exchange
rate movements. Deposits and loans in a foreign currency (USD in this
case) are, however, equivalent to their net present value, which is directly
affected by the exchange rate. On the other hand, the hedge will only be
exact to the extent that the interest rates used to discount the cashflows
reflect the interest rates implicit in the forward exchange rates. The amount
of the hedge required will also change as interest rates change, so that a
hedged position will not remain hedged. In practice the exposure might, for
example, be reassessed daily.
It is worth noting that a dealer who wishes to avoid this tail effect can
largely do so by trading ERAs rather than forward-forwards, as ERAs are
settled on the movement in forward points only. The dealer would, however,
still be vulnerable to the “magnification” effect mentioned.
In forward transaction exposures, other elements, such as interest to be
paid and received (rather than only interest already accrued), and the principal of a loan or deposit itself, should also be hedged.
188
7 · Foreign Exchange
EXERCISES
61. The Eurosterling interest rate for one year (exactly 365 days) is 13%. The
EuroDeutschemark interest rate for the same period is 9%. The spot rate today
is GBP/DEM 2.5580 / 90.
What would you expect the GBP/DEM swap price to be for one year forward?
(Ignore the buy–sell spread and calculate the middle price only.)
62.
USD/DEM
USD/FRF
GBP/USD
Spot
1.5140 / 45
5.1020 / 40
1.9490 / 00
3-month forward swap
29 / 32
246 / 259
268 / 265
Based on the prices above, what are the two-way prices for:
a.
DEM/FRF spot? Which side does the customer buy FRF?
b.
GBP/FRF spot? Which side does the customer sell GBP?
c.
USD/FRF 3 months forward outright?
d.
GBP/USD 3 months forward outright?
e.
GBP/FRF 3 months forward outright? Which currency has higher
interest rates?
f.
DEM/FRF 3 months forward outright? Which currency has higher
interest rates?
g.
DEM/FRF 3 months forward swap?
63.
USD/FRF
GBP/USD
Spot
5.1020 / 40
1.9490 / 00
O/N
2.0 / 2.5
10.6 / 10.1
T/N
2.3 / 2.9
3.5 / 3.3
S/W
18 / 20
23 / 22
1 month
96 / 94
Based on the prices above, what are the two-way prices for:
a.
USD/FRF forward outright value one week after spot?
b.
USD/FRF forward outright value tomorrow?
c.
USD/FRF forward outright value today? Which side does the customer
buy FRF?
d.
GBP/USD forward outright value today? Which side does the customer
buy GBP?
e.
GBP/USD forward-forward swap from one week after spot to one month
after spot? Which side does the customer buy and sell GBP (in that order)?
f.
GBP/USD forward-forward swap from tomorrow to one month after spot?
Which side does the customer buy and sell GBP (in that order)?
64. You are a bank FX dealer. Looking at the Reuters screen, you see the
following rates:
189
Part 3 · Foreign Exchange
USD/FRF spot:
T/N:
3 months:
6 months:
6.2695 / 15
2.5 / 1.5
310 / 290
550 / 510
USD/NOK spot:
T/N:
3 months:
6 months:
6.7620 / 40
0.2 / 0.5
15 / 15 A/P
50 / 100
a.
Some time ago, your customer sold NOK receivables forward into FRF, and
that deal matures on the date which is now the 3-month forward date.
However, he now discovers that these receivables will be delayed by three
months because of late delivery of the goods. He therefore needs to adjust the
forward deal. What forward-forward swap price do you quote him? He asks for
a two-way price and prefers to have it quoted in terms of number of FRF per 1
NOK. Which side of the price do you deal on?
b.
Your customer has another deal to sell NOK and buy FRF, also previously
undertaken, also maturing on the three-month forward date. He discovers first
thing in the morning that he needs the FRF by tomorrow and that he will have
enough NOK in his account tomorrow to cover this. He therefore uses another
forward-forward deal to adjust this second deal in order to take delivery of it
tomorrow. Again, what two-way price do you quote, and on which side do you
deal?
65. Today is Friday 19 April. You are a bank FX dealer. You look at your Reuters
screen and see the following rates quoted:
190
USD/FRF
Spot:
S/W:
1 month:
2 months:
5.2580
25
100
195
/ 00
/ 23
/ 90
/ 175
GBP/USD
Spot:
O/N:
T/N:
S/W:
1 month:
2 months:
1.9157
– 0.4
1.5
11
50
105
/ 67
/ +0.1
/
1
/
9
/ 45
/ 95
a.
Some time ago, your customer sold GBP forward against FRF for delivery on 3
June. He now discovers that he will need the FRF on 30 April instead. He
therefore asks you for a swap price to adjust the deal’s maturity date. What
price do you quote (in terms of FRF per 1 GBP)?
b.
Some time ago, you bought GBP from your customer against USD, and the
deal matures today. He discovers (early enough) that he does not have the
GBP in his account, and will not have them until 30 April. He asks you for a
two-way price to swap the deal from today until 30 April. What price do you
quote? On which side of the price do you deal?
7 · Foreign Exchange
c.
He has discovered that he is not in fact going to receive the GBP in (b) at all,
and decides to reverse the contract he made some time ago. He therefore
asks you for a two-way outright value today price. What price do you quote?
On which side of the price do you deal?
66. You are a bank FX dealer. You look at your Reuters screen and see the following rates quoted:
USD/DEM spot:
USD/ITL
spot:
USD/ITL
6-month swap:
USD
ITL
6-month interest rates:
6-month interest rates:
1.6012 / 22
1633.25 / 25
2237 / 2287
5.25 / 5.375%
8.00 / 8.25%
The 6-month value date is 182 days after spot value date.
a. Your customer needs to convert his ITL receivables into USD in six months’
time. What two-way forward outright price would you quote for this? Is the
ITL at a discount or a premium to the USD? On which side of the price
would you deal?
b. He is not necessarily in a hurry to do this transaction, because he thinks that
the spot exchange rate will get better for him. He expects the USD/DEM to
strengthen to 1.6150 over the next two days, but believes that the ITL is
likely to move from its present level of 1020 against the DEM to 1005.
He also believes that USD interest rates will fall 0.75% but that ITL rates
will probably rise 1.0% at the same time.
Should he sell the ITL forward now, or wait two days?
67. An investor has DEM15 million to invest for three months. He has a choice between
two possible investments – either a DEM deposit, or USD Eurocommercial paper
which could be hedged back into DEM (covered interest arbitrage). The
Eurocommercial paper would yield LIBOR + 4 basis points. If he invests via the
Eurocommercial paper, what is his absolute all-in rate of return, and what is this relative to Deutschemark LIBOR?
Spot USD/DEM
3-month swap:
3-month USD%:
3-month DEM%:
1.6730 / 40
173 / 168
8 4-1 / 8 8-3 %
4 8-1 / 4 -14 %
Assume that a mismatch of principal amounts is possible in the foreign
exchange swap, and that the 3-month period has 91 days.
68. Market rates now are as follows for EuroUSD and EuroSEK:
USD/SEK
Spot
6.0000 / 10
3 months (91 days)
590 / 605
6 months (182 days) 1274 / 1304
9 months (273 days) 1832 / 1872
FRA 3 v 9
USD%
SEK%
5.87 / 6.00
5.75 / 5.87
5.75 / 5.87
5.70 / 5.75
9.87 / 10.00
10.12 / 10.25
10.00 / 10.12
Market rates three months later are as follows:
191
Part 3 · Foreign Exchange
Spot
3 months (91 days)
6 months (182 days)
9 months (274 days)
USD/SEK
6.2060 / 65
649 / 664
1394 / 1424
2014 / 2054
USD%
SEK%
6.00 / 6.12
5.87 / 6.00
5.87 / 6.00
10.25 / 10.37
10.50 / 10.62
10.37 / 10.50
What would be the effective synthetic forward-forward 3 v 9 cost for SEK for a
borrower, created from an FRA 3 v 9 for USD, and all necessary forward foreign
exchange deals, taking into account all the relevant bid / offer spreads? Show all
the deals necessary based on an amount of SEK 1 million and assume that you
are a price-taker.
69. You undertake the following two USD/DEM forward swap deals for value spot
against 6 months (182 days):
a.
You buy and sell USD 10 million at 1.6510 and 1.6350.
b.
You sell and buy USD 10 million at 1.6495 and 1.6325.
6-month interest rates are as follows:
USD:
DEM:
6.5%
4.5%
What is the NPV of your position?
70. You are USD-based and have the following transactions on your books:
•
•
•
A 6-month (182 days) forward purchase of DEM 10 million.
•
A deposit placed with a counterparty of DEM 10 million at 6.5% for
3 months (91 days).
A 12-month (365 days) forward sale of DEM 10 million.
A borrowing from a counterparty of DEM 10 million at 7% for 12 months
(365 days; all the interest paid at maturity).
Rates are currently as follows:
Spot:
3 months:
6 months:
12 months:
192
USD/DEM
1.8000
1.8040
1.8088
1.8170
USD%
DEM%
6.5
6.5
7.0
7.4
7.5
8.0
a.
Suppose that the spot exchange rate moves to 2.0000 but interest rates
are unchanged. What is the effect on the profit and loss account, not considering discounting?
b.
What is the effect considering discounting, and what spot USD/DEM deal
would provide a hedge against this risk?
Part 4
Swaps and Options
193
■
■
■
“Any swap is effectively an
exchange of one set of cashflows
for another, considered to be of
equal value. The concept of a
basic interest rate swap is similar
to an FRA, but is applied to a
series of cashflows over a longer
period of time rather than to a
single period.”
194
8
Interest Rate and
Currency Swaps
Basic concepts and applications
Pricing
Valuing swaps
Hedging an interest rate swap
Amortising and forward-start swaps
Currency swaps
Exercises
195
Part 4 · Swaps and Options
BASIC CONCEPTS AND APPLICATIONS
Any swap is effectively the exchange of one set of cashflows for another considered to be of equal value. The concept of a basic interest rate swap in
particular is very similar to an FRA, but is applied to a series of cashflows
over a longer period of time, rather than to a single borrowing period.
Hedging borrowing costs
Consider, for example, the case we examined in the chapter on FRAs, of a
borrower who uses an FRA to hedge the cost of a single three-month borrowing due to begin in two months’ time, by buying a 2 v 5 FRA:
Fig 8.1
Hedging with an FRA
Receive LIBOR
on FRA
LIBOR + lending margin
paid to cash lender
Borrower
Pay fixed FRA rate
on FRA
In this case, the borrower’s net cost is (fixed FRA rate + lending margin).
Now consider the case of a borrower who takes a 5-year borrowing now
and on which she will pay LIBOR refixed at 3-monthly intervals throughout
the life of the borrowing. The cost of the first 3-month period is already fixed
at the current LIBOR. The borrower could fix the cost of the second 3-month
period of the borrowing with a 3 v 6 FRA. She could also fix the cost of the
third 3-month period with a 6 v 9 FRA, and so on. However, if she wishes to
hedge the cost of all the 3-month LIBOR settings throughout the 5 years, she
would use an interest rate swap, which achieves exactly this (see Figure 8.2).
Fig 8.2
Hedging with an interest rate swap
LIBOR + lending margin paid
to cash lender each 3 months
Receive LIBOR each
3 months on swap
Borrower
Pay fixed swap
rate on swap
In this case, the borrower’s net cost is (fixed swap rate + lending margin). The
fixed rate quoted to the borrower by the swap dealer applies throughout the
196
8 · Interest Rate and Currency Swaps
5-year period of the swap. The fixed rate may be paid for example 3-monthly,
6-monthly or annually, depending on the exact terms of the swap. The floating
rate may be 1-month LIBOR, 3-month LIBOR, 6-month LIBOR etc. A basic
interest rate swap is quoted as a fixed interest rate on one side and LIBOR
exactly on the other (rather than say, LIBOR + margin or LIBOR – margin). The
fixed and floating payments may not have the same frequency. For example the
fixed rate may be paid annually, but the floating rate may be based on 6-month
LIBOR and paid semi-annually.
As with an FRA, an interest rate swap involves no exchange of principal.
Only the interest flows are exchanged and, in practice, again as with an FRA,
these are netted rather than transferred gross in both directions. An important mechanical difference is that the settlement amount in a swap is
generally paid at the end of the relevant period (rather than at the beginning
on a discounted basis as in an FRA).
The motivation for the borrower in the example above may be that she
formerly expected interest rates to fall (and therefore took a floating rate
borrowing), but now expects interest rates to rise – that is, she has changed
her view. An alternative motivation could be that, regardless of her view, she
has existing floating-rate funding but for commercial purposes needs fixedrate funding (for example, a company funding a long-term project).
An interest rate swap is an exchange of one set of interest flows
for another, with no exchange of principal
Key Point
Relative advantage in borrowing
One particular driving force behind the swap market is the existence of
cost discrepancies between different funding methods, as shown by the following example:
Example 8.1
Each of the following two companies wishes to borrow for 5 years and each has
access to both fixed-rate borrowing and floating-rate borrowing:
Company AAA has access to floating-rate borrowing at LIBOR + 0.1% and also has
access to fixed-rate borrowing at 8.0%. Company AAA would prefer floating-rate
borrowing.
Company BBB has access to floating-rate borrowing at LIBOR + 0.8% and also
has access to fixed-rate borrowing at 9.5%. Company BBB would prefer fixedrate borrowing.
If AAA borrows at LIBOR + 0.1% and BBB borrows at 9.5%, each company
achieves what it requires. There is however a structure which achieves the same
result at a lower cost. This is for AAA to take a fixed-rate borrowing at 8.0%, BBB
to take a floating-rate borrowing at LIBOR + 0.8% and for AAA and BBB to transact a swap at 8.3% (which we will assume to be the current market rate for a swap)
against LIBOR as follows:
197
Part 4 · Swaps and Options
8.0%
paid to lender
8.3%
AAA
Swap
LIBOR + 0.8%
BBB
paid to lender
LIBOR
The net cost for AAA is: (8.0% – 8.3% + LIBOR) = LIBOR – 0.3%
The net cost for BBB is: (LIBOR + 0.8% + 8.3% – LIBOR) = 9.1%
In this way, each company achieves what it requires, but at a cost which is 0.4%
lower than it would achieve by the “straightforward” route.
In the example above, BBB’s borrowing costs are higher than AAA’s
whether we are comparing fixed-rate or floating-rate borrowing. However,
the difference between their costs is greater in the fixed-rate market (9.5%
compared with 8.0%) than in the floating-rate market (LIBOR + 0.8% compared with LIBOR + 0.1%). It is this discrepancy – which does arise in
practice – which makes the structure of the example possible. Company BBB
has an absolute cost disadvantage compared with company AAA in either
market. However, BBB’s relative advantage is in the floating-rate market and
AAA’s relative advantage is in the fixed-rate market. It is therefore more
cost-efficient for each company to borrow where it has a relative advantage
and then swap.
In practice, each company is likely to deal with a bank rather than
another company. The bank, whose role is to make a market in swaps, is
unlikely to deal with two offsetting counterparties in this way at the same
moment for the same period and the same amount. Nevertheless, the simplified example above demonstrates what is an important force behind the
existence of the swap market.
Typically, the structure described above might involve company AAA in
issuing a fixed-rate bond and simultaneously arranging the swap. The bond
issue would give rise to various costs – issuing fees, underwriting fees etc. –
which would not arise in a straightforward floating-rate borrowing, and
these need to be taken into account by AAA in calculating its all-in net floating-rate cost after the swap.
This “arbitrage” between different borrowing markets can be extended.
Suppose that a company arranges to borrow at a floating rate based on
something other than LIBOR. For example, the company might be in a
position to issue commercial paper. If it believes that its cost of borrowing
through CP will average less than its cost would be based on a margin
over LIBOR over 5 years, it could use a rolling CP borrowing programme
instead. Clearly this leaves the company vulnerable to the risk that its CP
costs may increase relative to LIBOR because the market’s perception of
the company’s credit rating worsens, or because investors’ demand for CP
falls. The company may nevertheless be prepared to take this risk in return
for a possible advantage.
198
8 · Interest Rate and Currency Swaps
Seeking an advantage from CP funding
Fig 8.3
Pay CP rate
to investors
Receive LIBOR
on swap
Company
Pay fixed rate
on swap
The net result of such an arrangement will be a borrowing cost of (fixed
swap rate – (LIBOR – CP rate)). As long as the CP rate is below LIBOR, the
borrowing cost will be less than the fixed swap rate. If the CP rate rises relative to LIBOR however, so will the all-in cost.
Asset swap
The examples we have used so far have been based on an underlying borrowing. That is, the “end-user” undertaking the swap has an underlying
borrowing and wishes to change the character of the borrowing from fixedrate to floating-rate or vice versa.
A swap can, however, be used by an investor just as well as by a borrower. An investor might for example buy an FRN and also transact a swap
to receive a fixed interest rate and pay LIBOR. The result would be a synthetic fixed rate investment. A swap with an underlying asset like this is
called an asset swap, while a swap with an underlying liability is called a liability swap. The swap itself is the same in both cases; the “asset” or
“liability” tag refers to the package of which it forms a part.
Fig 8.4
Asset swap
Receive fixed income
from investment
Pay fixed rate
on swap
Investor
Receive floating
rate on swap
Speculation
As with any instrument, a swap may be used for speculation as well as hedging.
A dealer deliberately taking a position with a swap is speculating that
long-term yields will move up or down. If he expects yields to rise, for example, he will undertake a swap where he is paying out the fixed interest rate
and receiving LIBOR. If he is correct, he can later offset this with a swap, for
the same period, where he is paying LIBOR and receiving the fixed interest
rate – which will then be at a higher level, giving him a profit:
199
Part 4 · Swaps and Options
Fig 8.5
Closing out an interest rate swap position
Pay LIBOR on
second swap
Receive LIBOR
on first swap
Swap dealer
Receive higher fixed
rate on second swap
Pay fixed rate on
first swap
Basis swap
As described so far, an interest rate swap involves the payment of a fixed
interest rate in one direction and a floating interest rate in the other direction. This is known as a “coupon swap”. A swap can alternatively involve
two differently defined floating rates – for example, the payment of LIBOR
and the receipt of a rate based on commercial paper rates. Such a floatingfloating swap is called a “basis swap”. “Index swaps” can also be
constructed, where the flows in one or other direction are based on an index
(such as a stock index, for example).
PRICING
Day/year conventions
The day/year conventions for calculating interest payments on swaps are
largely the same as we have already seen for money market and bond calculations – that is, ACT/360, ACT/365, ACT/ACT, 30(E)/360 or 30(A)/360.
There are a few points to mention, however.
Modified following
In the bond market, we have already seen that if a regular coupon date falls
on a weekend or holiday, the payment is generally delayed until the next
working day but the amount of the payment is not changed.
In the money market, in the same circumstances, the payment is delayed
until the next working day unless this would move into the following calendar month, in which case the payment is made on the previous working day.
In either case, the amount of the payment is calculated to the actual payment
date, not the regular date.
The usual convention in the swap market is the same as in the money
market and is called the “modified following” method. This can mean that
the cashflows in a swap and a bond, which are intended to match precisely,
are in fact slightly different in timing and amount.
200
8 · Interest Rate and Currency Swaps
ACT/ACT
In a swap, calculation of an interest payment on an ACT/ACT basis is split
between that part of the interest period falling in a leap year, which is
divided by 366, and the remainder, which is divided by 365.
Example 8.2
The fixed leg of a swap is based on 10% ACT/ACT (annual). What is the amount of
the fixed payment for the period 15 October 1999 to 15 October 2000?
15 October 1999 to 31 December 1999 (inclusive):
1 January 2000 to 14 October 2000 (inclusive):
(
Interest amount is therefore 10% ×
78 days
288 days
78
288
+ 10% ×
365
366
) (
)
ACT/365
In swap documentation (as in standard ISDA documentation, for example),
the expression “ACT/365” is sometimes used as an alternative for
ACT/ACT, and the expression “ACT/365 (fixed)” is sometimes used instead
for what we have defined in this book as ACT/365.
Converting between different quotation bases
The basis for quoting the rate on the fixed leg of a swap might be annual, or
semi-annual, quarterly, monthly etc. As we have seen above, it may also be
on a bond basis or a money market basis. We need to be able to convert
between these different bases.
In this context, the market uses the expression “money market basis” to
mean ACT/360. The term “bond basis” is used to mean ACT/365,
ACT/ACT or 30/360. Over a non-leap year, these three are equivalent over a
whole year (because ´eyt
–
–
¥† = ´eyp
¥π = 1).
Example 8.3
Convert a USD interest rate of 10.3% SABB (semi-annual bond basis) to the AMM
(annual money market) equivalent.
2
– 1] = 10.565% ABB
[(1 + 0.103
2 )
10.565% ×
360
= 10.420% AMM
365
Answer: 10.42% AMM
Example 8.4
Convert a DEM interest rate of 6.40% ABB (annual bond basis) to the SAMM
(semi-annual money market) equivalent.
201
Part 4 · Swaps and Options
(i)
[(1.064) – 1] × 2 = 6.301% SABB
360
= 6.214% SAMM
365
(ii) 6.301% ×
Answer: 6.21% SAMM
The conversions between annual and semi-annual in Examples 8.3 and 8.4
are the conversions we saw in the “Financial Arithmetic Basics” chapter,
between effective and nominal rates. When we discussed effective rates on
a 360-day basis in the “Money Market” chapter however, we saw that it is
not possible to make this conversion precisely for rates on a money market
basis (ACT/360).
Suppose that in Example 8.4, we try to compound the 6.214% SAMM
directly to AMM:
(
(iii) 1 +
0.06214
2
2
)
– 1 = 6.311% AMM
If we now finally try to convert back to ABB again, we have:
365
= 6.399% ABB
360
(iv) 6.311% ×
This is almost the same as the 6.40% ABB with which we began in Example
8.4, but not quite. This is because step (iii) above is not valid. Essentially, we
can convert between the various bases but completing the square below
between SAMM and AMM is only approximate because it would be compounding on a 360-day basis rather than an annual basis:
Conversion between different quotation bases
Fig 8.6
₂
SABB = ((1 + ABB) – 1) × 2
SABB
ABB
2
ABB = (1 + SABB ) – 1
2
SAMM =
360
365
SABB ×
SABB =
SAMM ×
AMM =
360
ABB ×
365
365
360
ABB =
AMM ×
₂
SAMM ~ ((1 + AMM) – 1) × 2
SAMM
AMM
2
AMM ~ (1 + SAMM ) – 1
2
202
365
360
8 · Interest Rate and Currency Swaps
The following example uses the conversions we have seen above to calculate
the approximate net result of an asset swap. We have repeated the example
later (see Example 8.11) using exact cashflows and zero-coupon discount factors to calculate a slightly different result.
Example 8.5
An investor purchases a 3-year bond yielding 10.686% (annual bond basis). He
transacts a swap to pay 10.3% (annual bond basis) against 6-month LIBOR (semiannual money market basis). What is the net yield to the investor of this asset swap?
10.686% (ABB)
from bond
10.3% (ABB)
Investor
Swap
LIBOR
Income from bond: 10.686% (ABB) = 10.415% (SABB) = 10.272% (SAMM)
Payment in swap: 10.300% (ABB) = 10.048% (SABB) = 9.910% (SAMM)
Receipt in swap:
LIBOR (SAMM)
Net yield:
LIBOR + 0.362% (SAMM)
The investor can therefore achieve an all-in yield on the asset swap of around 36
basis points over LIBOR.
Prices quoted as a spread over government bonds
Swap rates are sometimes quoted as a “spread” over government bond yields
– particularly for example in the USD swap market, where there is a good
series of government bonds available. In this case, the market is taking the
current yield for the government bond of the nearest maturity which is “on
the run” – that is, the benchmark bond which has been issued recently and
will generally be trading near par. The two-sided swap price quoted is the
difference between this yield and the swap rate.
Example 8.6
The 5-year USD swap is quoted as 33 / 37 over treasuries. The current 5-year
treasury note yield is 7.43%. What is the swap rate on an AMM (annual money
market) basis?
US treasuries always pay semi-annual coupons. The 7.43% yield and spread are
therefore SABB. Therefore the swap rate is:
(7.43 + 0.33)% / (7.43 + 0.37)% = 7.76% / 7.80% SABB
2
360
– 1] ×
= 7.802%
[(1 + 0.0776
2 )
365
360
– 1] ×
= 7.843%
[(1 + 0.0780
2 )
365
2
The AMM equivalent is therefore 7.80% / 7.84%
203
Part 4 · Swaps and Options
The pricing link between FRAs and interest rate swaps
Since it is possible to fix in advance the cost of borrowing from 3 months
to 6 months (an FRA 3 v 6), from 6 months to 9 months, from 9 months to
12 months etc., it must be possible to fix the cost for all these at once,
giving a fixed cost for the whole period. This is the same process as when
we constructed strips in the chapters on Forward-forwards and FRAs and
Futures. There should theoretically be no arbitrage between the result of
doing this and the result of a single interest rate swap for the whole period.
This is because borrowing on a rolling 3-month basis at LIBOR and at the
same time transacting a swap to receive 3-month LIBOR quarterly against
a fixed payment, is an alternative to borrowing on a rolling 3-month basis
at LIBOR and fixing the cost with a series of rolling FRAs. It is possible to
arbitrage between the swap and the futures contracts if they are out of line.
For example, if the swap rate is too high, a dealer could transact a swap to
receive the fixed rate and pay LIBOR; at the same time, he would sell a
strip of futures (or buy a strip of FRAs) to offset this. This therefore gives a
method of arriving at a swap price derived from FRA rates (or equivalently, short-term futures prices).
Example 8.7
Suppose the following rates are available for borrowing dollars:
3-month LIBOR
FRA
3v6
6v9
9 v 12
14.0625%
12.42%
11.57%
11.25%
(91 days)
(91 days)
(91 days)
(92 days)
It is possible to do the following:
•
Borrow USD 1 now for 3 months. At end of 3 months, repay:
(
USD 1 + 0.140625 ×
•
91
= USD 1.03555
360
)
Arrange an FRA 3 v 6 at 12.42 on an amount of USD 1.03555. Considering the
FRA settlement as made after 6 months rather than made on a discounted
basis after 3 months, this gives a total repayment at the end of 6 months of:
(
USD 1.03555 × 1 + 0.1242 ×
•
(
91
= USD 1.09929
360
)
Similarly, after 9 months, borrow USD 1.09929 for 3 months, fixed at an FRA
9 v 12 cost of 11.25%, and at the end of 12 months repay:
(
USD 1.09929 × 1 + 0.1125 ×
204
)
Similarly, after 6 months, borrow USD 1.06806 for 3 months, fixed at an FRA
6 v 9 cost of 11.57%, and at the end of 9 months repay:
USD 1.06806 × 1 + 0.1157 ×
•
91
= USD 1.06806
360
92
= USD 1.13090
360
)
8 · Interest Rate and Currency Swaps
The effect of this is a fixed cost at the end of 12 months of 13.09%. This should
therefore be the rate for a 12-month interest rate swap on an annual basis against
quarterly LIBOR payments.
The rate of 13.090% is on a bond basis, not a money market basis, even though
the FRA rates from which it has been constructed are quoted on a money market
basis. This is because “bond basis” represents the cash interest amount paid by
the end of 365 days – which is what we have calculated – while “money market
basis” represents the cash interest amount paid by the end of 360 days.
To convert from this annual bond basis to an equivalent quarterly bond basis, we
could decompound as before to give:
((1 + 0.13090)
1
–
4
– 1) × 4 = 12.49% (QBB)
The equivalent quarterly money market swap rate for 1 year against 3-month
LIBOR would then be calculated as:
12.49% ×
360
= 12.32% (QMM)
365
Note however that following Example 8.8, we calculate a slightly different result for this.
Example 8.7 gave a 1-year swap rate of 13.090% on a bond basis. We can use the
same process to construct swap rates for other maturities: 3 months, 6 months, 9
months, 15 months, 18 months etc. As long as forward-forward prices are available (either as FRAs or futures) for the periods leading up to the swap maturity,
we can construct a strip. The result in each case is a zero-coupon swap rate, as the
strip process rolls all the interest to an accumulated total at the end maturity.
If we calculate a series of zero-coupon swap rates in this way, we then
have a set of discount factors for valuing cashflows. In the chapter on Zerocoupon Rates and Yield Curves, we used zero-coupon discount factors to
calculate the theoretical par bond yield. In exactly the same way, we can use
the zero-coupon swap rates to calculate a swap rate.
The swap rates so constructed are called “par” swap rates. This refers to the
market rate on the fixed side of a swap, which is conventionally quoted so as
to be paid or received against LIBOR exactly on the other side. It may be (as in
Example 8.11 below) that the final swap structure agreed involves the payment
or receipt of an off-market fixed swap rate, in return for an amount which represents LIBOR plus or minus some compensating spread. Such an off-market
swap structure may result in more convenient cashflows for one of the parties.
Example 8.8
Suppose we have the following rates (the first four are the same as in Example 8.7).
What is the 2-year par swap rate on a quarterly money market basis?
3-month LIBOR
FRA
3v6
6v9
9 v 12
12 v 15
15 v 18
18 v 21
21 v 24
14.0625%
12.42%
11.57%
11.25%
11.00%
10.90%
10.80%
10.70%
(91 days)
(91 days)
(91 days)
(92 days)
(91 days)
(91 days)
(91 days)
(92 days)
205
Part 4 · Swaps and Options
From Example 8.7, we know that if we borrow USD 1 now for 3 months, we repay
USD 1.03555 at the end of the period. Therefore the 3-month discount factor is:
1
= 0.9657
1.03555
Using the other results from example 8.7, we have the discount factor for 6 months as:
1
= 0.9363
1.06806
and for 9 months as:
1
= 0.9097
1.09929
and for 12 months as:
1
= 0.8843
1.13090
We can now extend the strip process for the next year:
(
for 15 months: USD 1.13090 × 1 + 0.1100 ×
discount factor =
(
(
)
91
= USD 1.22699
360
)
1
= 0.8150
1.22699
(
for 24 months: USD 1.22699 × 1 + 0.1070 ×
discount factor =
91
= USD 1.19438
360
1
= 0.8373
1.19438
for 21 months: USD 1.19438 × 1 + 0.1080 ×
discount factor =
)
1
= 0.8603
1.16235
for 18 months: USD 1.16235 × 1 + 0.1090 ×
discount factor =
91
= USD 1.16235
360
92
= USD 1.26054
360
)
1
= 0.7933
1.26054
We can now use these discount factors to calculate the 2-year par swap rate, exactly
as in the first example in the chapter on Zero-coupon Rates and Yield Curves. If i is
the 2-year swap rate on a quarterly money market basis, then we have:
(
91
91
91
× 0.9657 + i ×
× 0.9363 + i ×
× 0.9097
360
360
360
) (
) (
)
92
91
91
× 0.8843) + (i ×
× 0.8603) + (i ×
× 0.8373)
+ (i ×
360
360
360
91
92
× 0.8150) + ((1 + i ×
× 0.7933)
+ (i ×
360
360 )
1= i×
The solution to this is i = 11.65%
206
8 · Interest Rate and Currency Swaps
The same approach of valuing the cashflows in a par swap can be applied to
the simpler case of a 1-year par swap on a quarterly money market basis. If
this rate is i, then using the same discount factors as above, we have:
(
1= i×
) (
) (
)
91
91
91
× 0.9657 + i ×
× 0.9363 + i ×
× 0.9097 +
360
360
360
92
1+i×
× 0.8843
360
((
)
)
The solution to this is i = 12.35%
This is not the same result as the 12.32% calculated in Example 8.7. The
reason is that we have now discounted each cashflow precisely using an
appropriate discount rate. In Example 8.7, however, we decompounded from
an annual rate to a quarterly rate. This decompounding process is circular –
the interest rate used for discounting is the same as the decompounded result
itself. The answer we now have of 12.35% is a more accurate answer based
on the data available.
Pricing interest rate swaps from futures or FRAs
Calculation
summary
• for each successive futures maturity, create a strip to generate a
•
discount factor
use the series of discount factors to calculate the yield of a par swap
Pricing longer-term swaps
The last two examples provide a pricing method for interest rate swaps for as
far forward in maturity as there are futures contracts available. If futures or
FRAs are not available up to the maturity of an interest rate swap however,
there is not such a precise arbitrage structure to calculate a swap rate.
Longer-term swap rates must however be linked to capital market yields. In
Example 8.1, we considered how company AAA achieved a lower LIBORbased borrowing cost than it could otherwise have done, by combining a
fixed-rate bond issue with a swap. In that example, where we ignored any
fees associated with issuing a bond and any cost of intermediation by a bank,
a swap rate of 7.9% would have given company AAA an all-in borrowing
cost of (8.0% – 7.9% + LIBOR) = LIBOR + 0.1% – which is exactly the
same as the cost achieved through a straightforward LIBOR-based borrowing. It was therefore necessary for the swap rate to be higher than around
7.9% in order for AAA to achieve a lower cost through the liability swap
structure (we are ignoring here any differences between annual and semiannual, or money market and bond basis).
On the other hand, a swap rate of 8.7% would have given company BBB an
all-in borrowing cost of (LIBOR + 0.8% + 8.7% – LIBOR) = 9.5% – which is
exactly the same as the cost achieved through a straightforward fixed-rate borrowing. It was therefore necessary for the swap rate to be less than around
8.7% in order for BBB to achieve a lower cost through the swap structure.
207
Part 4 · Swaps and Options
Although the available borrowing costs in Example 8.1 are hypothetical,
this shows the type of considerations which generate the swap rate available
in the market. As in other markets, it is the rate at which supply and demand
balance. Supply and demand will be affected by borrowing and investment
rates available to a wide range of market participants, with a range of different opportunities and fee structures.
VALUING SWAPS
Marking-to-market a swap
To value an interest rate swap, we calculate its NPV, exactly as we value
other instruments. The most appropriate rates to use for discounting the
cashflows to present values are zero-coupon swap yields. A less satisfactory
alternative is to use the current par swap rate for the maturity of the swap we
are valuing. In the section “The pricing link between FRAs and interest rate
swaps”, we created shorter-term zero-coupon swap rates from strips of
FRAs. Longer-term zero-coupon swap yields can be created by bootstrapping
from the par swap yield curve. This is done in exactly the same way as we
constructed zero-coupon bond yields in the chapter on Zero-coupon Rates
and Yield Curves. Instead of using a series of existing bonds for the bootstrapping process, we use a series of fictitious bonds, each of which has an
initial cost of 100 and a coupon equal to the par swap rate.
One complication is the valuation of the floating-rate side of the swap, as
the cashflows are not yet known. One approach is first to calculate, for each
period, the forward-forward interest rates consistent with the current yield
structure, and then to calculate each floating-rate cashflow assuming this forward-forward rate. Another approach – mathematically equivalent – is to
add to the schedule of actual swap cashflows a further set of fictitious cashflows which exactly offsets the unknown amounts. If the additional fictitious
cashflows can be arranged so that they have a zero NPV, the NPV that we
are trying to calculate will be unaffected. As we have offset the unknown
cashflows, we are left with an NPV which we can calculate.
The additional series of fictitious cashflows to be added is effectively a par
FRN. Assuming no change in credit risk, an FRN should be priced at par on
a coupon date. For example, issuing 100 of an FRN with a 6-monthly
coupon of LIBOR is equivalent to borrowing 100 at LIBOR for only six
months, and then repeatedly rolling the borrowing over at the end of each six
months. It follows that on a coupon date, 100 is the NPV of the future FRN
flows. Therefore a series of cashflows consisting of 100 in one direction at
the beginning, offset by future FRN flows in the other direction, has a zero
NPV. If these cashflows have a zero NPV on a future coupon date, they must
also have a zero NPV now. We can therefore add these flows to the swap
structure, beginning, at the next swap interest payment date, without changing the total NPV.
208
8 · Interest Rate and Currency Swaps
Example 8.9
Value the following interest rate swap on 27 March 1998:
Notional amount of swap:
Start of swap:
Maturity of swap:
Receive:
Pay:
Previous LIBOR fixing:
10 million
21 July 1997
21 July 2000
7.4% (annual 30/360)
LIBOR (semi-annual ACT/360)
9.3% from 21 January 1998 to 21 July 1998
The zero-coupon discount factors from 27 March 1998 are:
21 July 1998:
21 January 1999:
21 July 1999:
21 January 2000:
21 July 2000:
0.9703
0.9249
0.8825
0.8415
0.8010
The cashflows are as follows:
Date
21 July 1998:
Swap
+ 10 m × 7.4%
184
– 10 m × L1 × 360
–
21 Jan 1999:
21 July 1999:
+ 10 m × 7.4%
where:
181
– 10 m × L2 × 360
–
181
– 10 m × L3 × 360
–
21 Jan 2000:
21 July 2000:
181
– 10 m × 9.3% × 360
–
+ 10 m × 7.4%
182
– 10 m × L4 × 360
–
L1 is LIBOR from 21 July 1998 to 21 January 1999
L2 is LIBOR from 21 January 1999 to 21 July 1999
L3 is LIBOR from 21 July 1999 to 21 January 2000
L4 is LIBOR from 21 January 2000 to 21 July 2000
Method 1
From the discount factors, we can calculate forward-forward rates to substitute for
the unknown LIBOR fixings as follows:
L1:
360
– 1) ×
= 9.6039%
( 0.9703
0.9249
184
L2:
360
– 1) ×
= 9.5560%
( 0.9249
0.8825
181
L3:
360
– 1) ×
= 9.6907%
( 0.8825
0.8415
181
L4:
360
– 1) ×
= 10.0012%
( 0.8415
0.8010
182
209
Part 4 · Swaps and Options
Using these rates, we have the following cashflows:
Date
Swap
Net cashflows
21 July 1998: +10 m × 7.4% – 10 m × 9.3% ×
– 10 m ×
21 Jan 1999:
21 July 1999: +10 m × 7.4% – 10 m ×
– 10 m ×
21 Jan 2000:
21 July 2000: +10 m × 7.4% – 10 m ×
181
–
360
+ 272,417
184
9.6039% × 360
–
181
9.5560% × 360
–
181
9.6907% × 360
–
182
10.0012% × 360
–
– 490,866
+ 259,546
– 487,227
+ 234,384
We can now value these net cashflows using the discount factors, to give:
(272,417 × 0.9703) + (–490,866 × 0.9249) + (259,546 × 0.8825) +
(–487,227 × 0.8415) + (234,384 × 0.8010) = –182,886
The swap is therefore showing a mark-to-market valuation of -182,886.
Method 2
Without upsetting the NPV valuation, we can add the cashflows for a fictitious “FRN
investment” of 10 million which starts on 21 July 1998, matures on 21 July 2000
and pays LIBOR, because the NPV of these cashflows will be zero on 21 July 1998
(and hence zero on 27 March 1998). The resulting cashflows will then be:
Date
21 July 1998:
Swap
+10 m × 7.4%
21 Jan 1999:
21 July 1999:
+10 m × 7.4%
21 Jan 2000:
21 July 2000:
+10 m × 7.4%
– 10 m × 9.3% ×
181
–
360
“FRN”
Net cashflows
– 10 m
+10 m × 7.4%
181
– 10 m × 9.3% × 360
–
– 10 m
184
– 10 m × L1 × 360
–
184
+10m × L1 × 360
–
181
– 10 m × L2 × 360
–
181
+10m × L2 × 360
–
– 10 m × L3 ×
181
–
360
+10m × L3 ×
– 10 m × L4 ×
182
–
360
182
+10m × L4 × 360
–
+10m
+10 m × 7.4%
182
–
360
+10 m × 7.4%
+10 m
We can now value these cashflows using the discount factors to give:
(–9,727,583 × 0.9703) + (740,000 × 0.8825) + (10,740,000 × 0.8010) = –182,884
Reversing a swap transaction
Suppose that a dealer or customer, who has previously entered into a swap
transaction, now wishes to close out this position. He can transact another
swap in the opposite direction for the remaining term of the existing swap. If
he has previously dealt a swap to pay a fixed rate and receive LIBOR, for
example, he can now deal instead to receive a fixed rate and pay LIBOR. The
LIBOR cashflows will balance but, because the fixed rate on the new swap is
unlikely to be the same as the fixed rate on the old swap, there will be a net
difference in the fixed amount on each future payment date. This difference
may be a net receipt or a net payment.
210
8 · Interest Rate and Currency Swaps
Rather than put a new swap on the books however, if the counterparty in
the new swap is the same as the counterparty in the original swap, it may
well be preferable for both parties to settle immediately the difference
between the original swap rate and the new swap rate. This would reduce
both credit line utilisation and capital adequacy requirements. In order to
settle immediately, the potential future cashflows – the difference between
the two fixed rates – need to be valued. This is done, as usual, by calculating
the NPV of these net cashflows. This NPV is then paid by one party to the
other, the original swap is cancelled and no new swap is transacted.
Example 8.10
We have on our books the swap already described in Example 8.9. For value on 21
July 1998, we decide to reverse the swap. The same counterparty quotes a swap
rate of 8.25% then for the remaining 2 years. What should the settlement amount
be to close out the swap position, using the following discount factors?
21 July 1999:
21 July 2000:
0.9250
0.8530
The LIBOR-based flows on the two swaps offset each other exactly. The remaining
flows are then:
Date
21 July 1999
21 July 2000
Original swap
+10 m × 7.4%
+10 m × 7.4%
Reverse swap
– 10 m × 8.25%
– 10 m × 8.25%
Net cashflows
– 85,000
– 85,000
The NPV of the net cashflows is:
(–85,000 × 0.9250) + (–85,000 × 0.8530) = –151,130
We therefore pay the counterparty 151,130 to close out the existing swap.
Constructing an asset swap
The following example considers essentially the same asset swap as Example 8.5.
In this case however, we construct a par / par swap – that is, a package with
an initial principal amount invested, the same “par” principal amount
returned at maturity, and an income stream calculated as a constant spread
above or below LIBOR based on this same par amount. This is an asset swap
to create a synthetic FRN, priced at par and redeemed at par.
Example 8.11
An investor purchases the following bond and wishes to convert it to a synthetic
FRN with an asset swap:
Settlement date:
Maturity date:
Coupon:
Price:
Yield:
16 August 1998
16 August 2001
11.5% (annual)
102.00
10.686%
211
Part 4 · Swaps and Options
The 3-year par swap rate from 16 August 1998 is quoted at 10.2% / 10.3% (annual
30/360) against LIBOR (semi-annual, ACT/360). The investor would like a par / par
asset swap structure.
The discount factors from 16 August 1998 are given as follows:
16 February 1999:
16 August 1999:
16 February 2000:
16 August 2000:
16 February 2001:
16 August 2001:
0.9525
0.9080
0.8648
0.8229
0.7835
0.7452
Suppose that the principal amount invested is 102, and that the investor transacts
a “straightforward” swap based on a par amount of 100. The bond cashflows and
swap cashflows would then be as follows:
Date
Bond
16 Aug 1998:
– 102
Swap
+100 × LIBOR × 184
–
360
16 Feb 1999:
16 Aug 1999:
+ 11.5
– 100 × 10.3%
+100 × LIBOR × 184
–
360
16 Feb 2000:
16 Aug 2000:
+ 11.5
– 100 × 10.3%
+100 × LIBOR × 182
–
360
+100 × LIBOR × 184
–
360
16 Feb 2001:
16 Aug 2001:
181
+100 × LIBOR × 360
–
+ 100 +11.5
– 100 × 10.3%
181
+100 × LIBOR × 360
–
These cashflows will clearly not provide a “clean” result in terms of a spread relative to LIBOR based on a principal of 100, for two reasons. First, the difference
between the 11.5% coupon on the bond and the 10.3% swap rate is an annual
cashflow, but LIBOR is semi-annual. Second, the principal invested is 102 rather
than 100. These differences have an NPV of:
(11.5 – 100 × 10.3%) × 0.9080 + (11.5 – 100 × 10.3%) × 0.8229
+ (11.5 – 100 × 10.3 %) × 0.7452 + (100–102) = 0.9713
What interest rate i (ACT/360, semi-annual) is necessary so that a series of cashflows at i based on a principal of 100 would have the same NPV?
181
(100 × i × 184
– × .9525) + (100 × i × 360
– × .9080) + (100 × i × 184
– × .8648)
360
360
182
181
+ (100 × i × 360
– × .8229) + (100 × i × 184
– × .7835) + (100 × i × 360
– × .7452)
360
= 0.9713
The solution to this is: i = 0.0038
We can therefore replace the following fixed cashflows arising from a par swap:
annual 30/360 swap outflows of (100 × 10.3%)
plus an initial “odd” investment of 2,
by the following fixed cashflows – effectively an off-market swap:
annual 30/360 swap outflows of (100 × 11.5%)
plus semi-annual ACT/360 inflows of (100 × 0.38%).
This 0.38% can then be added to the semi-annual swap inflows of (100 × LIBOR)
which we already have. We have therefore replaced the par swap by one with the
same NPV as follows:
212
8 · Interest Rate and Currency Swaps
Receive:
Pay:
LIBOR + 0.38% (ACT/360, semi-annual)
11.5% (30/360, annual)
The net effect is therefore a par / par asset swap giving the investor LIBOR plus 38
basis points.
It is worth noting that the result of the last example is around 2 basis points
worse than the approximate result calculated in Example 8.5. This is because
in Example 8.5, the bond yield and swap rate are converted to semi-annual
rates by decompounding at their own respective semi-annual rates. In Example
8.11, all cashflows are discounted by the discount factors.
•
To value a swap, calculate the NPV of the cashflows, preferably using
zero-coupon swap yields or the equivalent discount factors.
•
To value floating-rate cashflows, superimpose offsetting floating-rate
cashflows known to have an NPV of zero – effectively an FRN.
•
•
A swap at current rates has an NPV of zero.
Calculation
summary
If a current swap involves an off-market fixed rate, this is compensated
by an adjustment to the other side of the swap, or by a one-off payment, so as to maintain the NPV at zero.
HEDGING AN INTEREST RATE SWAP
As with every instrument, a dealer may find he has a position which he does
not want – either because he has changed his mind about the direction of
interest rates, or because he has made a two-way price and been taken up on
it. He is therefore exposed to movements in the swap rate and will want to
hedge himself. This he can do in any of several ways:
(a) Deal an exactly offsetting swap.
(b) Deal in a different instrument which will give him offsetting flows.
Suppose for example that under the swap, the dealer is paying out a
fixed interest rate for 5 years. As a hedge, he might buy a 5-year bond –
or a bond with a modified duration the same as that of a bond with
coupons equal to the fixed swap rate. This will give him a fixed income
Fig 8.7
Hedging an interest rate swap
Swap
Bond
Pay fixed rate
Receive fixed rate
Swap dealer
Receive LIBOR
Pay LIBOR
Funding
213
Part 4 · Swaps and Options
to offset the fixed payment on the swap. In order to buy the bond, he can
fund himself at LIBOR or a rate linked to LIBOR.
In this way, he is hedged for as long as he holds the bond. If the dealer
does subsequently deal a second swap which offsets the first one, but 5year rates have fallen, he will make a loss. However, the bond will have
increased in value correspondingly. Clearly the hedge is not perfect, as
the swap dealer is exposed during this period to the risk that the swap
market does not move exactly in line with the bond he has used as a
hedge – a basis risk.
(c) Deal in bond futures or options. These may provide a liquid hedge, but the
hedge could be less perfect, as the specifications of the futures or options
contracts may imply a rather different maturity from the swap, so that the
hedge value does not respond to yield changes in the same way as the swap.
AMORTISING AND FORWARD-START SWAPS
Amortising swap
In practice, a company often needs an interest rate swap on a borrowing which
is amortising rather than one which has a bullet maturity – that is, the principal
is repaid in instalments over the life of the borrowing rather than all at maturity.
The borrowing may also be going to start at some time in the future, or already
have begun so that the next interest payment is at some period ahead.
Consider a 2-year borrowing of 200 beginning now, with floating rate
interest payments each 6 months and amortisations of 50 each 6 months. A
single interest rate swap for 200 over 2 years would not match the borrowing
profile, while 4 separate swaps of 50 each at different rates (one for
6 months, one for 1 year, one for eighteen months and one for 2 years)
would result in irregular interest flows. We therefore wish to create a single
swap rate for the amortising structure.
Suppose that the swap rates (semi-annual bond basis against 6-month
LIBOR) are as follows:
6 months
1 year
18 months
2 years
6.00% (this is equivalent to current 6 month LIBOR)
6.50%
7.00%
7.50%
We can calculate from these rates a set of zero-coupon discount factors
by bootstrapping in the same way as we did in Chapter 6. These can be
calculated to be:
6 months:
1 year:
18 months:
2 years:
0.9709
0.9380
0.9016
0.8623
If the single amortising swap rate is i, the cashflows on the borrowing plus
swap would be as follows:
214
8 · Interest Rate and Currency Swaps
Time
Cashflow
Now:
+200
6 months:
1 year:
18 months:
2 years:
( 2i )
i
–50 – (150 × )
2
i
–50 – (100 × )
2
i
–50 – (50 × )
2
–50 – 200 ×
If the single rate i is consistent with the swap yield curve, the NPV of these
flows will be zero:
(–50 – (200 × 2i )) × 0.9709 + (–50 – (150 × 2i )) × 0.9380
i
i
+ (–50 – (100 × )) × 0.9016 + (–50 – (50 × )) × 0.8623 + 200 = 0
2
2
The solution for this is i = 6.99%
Forward-start swap
Consider now an 18-month borrowing of 150 which will not start for 6
months and which will amortise at the rate of 50 each 6 months again. It is
possible to calculate the appropriate swap rate for this forward-start borrowing in exactly the same way. In this case, the cashflows are as follows:
Time
Cashflow
6 months:
+150
1 year:
18 months:
2 years:
( 2i )
i
–50 – (100 × )
2
i
–50 – (50 × )
2
–50 – 150 ×
Again, the NPV of these flows will be zero:
(–50 – (150 × 2i )) × 0.9380 + (–50 – (100 × 2i )) × 0.9016
i
+ (–50 – (50 × )) × 0.8623 + 150 × 0.9709 = 0
2
The solution for this is i = 7.69%
The forward-start amortising swap rate is therefore 7.69% (semi-annual
bond basis).
215
Part 4 · Swaps and Options
Calculation
summary
The current swap rate for a swap based on an irregular or forward-start
notional principal is again the rate which gives the swap an NPV of zero.
Delayed-start swap
A swap may be transacted to start only a short time in the future, in which
case the analysis in the last section can not conveniently be used. An alternative approach is to consider that the dealer will hedge himself in the same way
that he might when transacting a swap for immediate value – by buying or
selling a bond. In this case, however, the bond hedge will be immediate but the
swap will not. The dealer will therefore incur a positive or negative net cost of
carry – for example, the difference between the income on the bond and the
funding cost of buying the bond, if the hedge is a bond purchase. This will be
incurred for the period until the swap begins, at which time the hedge can be
reversed and the dealer can cover his position with an offsetting swap.
An adjustment should therefore be made to the fixed rate quoted for the
delayed-start swap. The NPV of this adjustment over the life of the swap
should be equal to the net cost of carry for the hedging period.
CURRENCY SWAPS
Currency swaps involve an exchange of cashflows largely analogous to those
in an interest rate swap, but in two different currencies. Thus one company
might establish – or have already established – a borrowing in one currency,
which it wishes to convert into a borrowing in another currency. One example would be where the existing borrowing, and the effective borrowing
arrangement after the swap, are both fixed rate – a fixed-fixed currency
swap. Currency swaps can also be fixed-floating or floating-floating. The
transaction is the conversion of a stream of cashflows in one currency into a
stream of cashflows in another currency.
It is important to note that, unlike an interest rate swap, a currency swap
which is based on a borrowing or an asset generally involves exchange of the
principal amount as well as the interest amounts. In a single-currency interest
rate swap, nothing would be achieved by this – each party would simply be
required to pay and receive the same principal amount, which would net to
zero. In a currency swap however, the value of the principal amount at maturity depends on the exchange rate. If this is not included in the swap, the
all-in result will not be known.
In order to exchange one cashflow stream for another, the two streams must
have the same value at the time of the transaction. The appropriate value of
each stream, as with other market instruments, is its NPV. To equate the two
NPVs which are in different currencies, we use the current spot exchange rate.
Calculation
summary
216
To value cashflows in a different currency,
convert the resulting NPV at the spot exchange rate.
8 · Interest Rate and Currency Swaps
Example 8.12
You purchase a 5-year USD bond with an annual coupon of 6.7%, at a price of
95.00. You convert this investment to a synthetic FRF investment on a par amount,
with an asset swap. The swap rate you achieve is 7.85% for USD against 8.35%
for FRF (both annual bond basis). The current exchange rate is 6.00. What all-in
FRF yield do you achieve?
coupon and principal
from USD bond
USD cashflows
Investor
Swap
FRF cashflows
The future USD cashflows are as follows for each USD 100 face value:
Year 1
Year 2
Year 3
Year 4
Year 5
+ 6.70
+ 6.70
+ 6.70
+ 6.70
+ 106.70
Discounting at a rate of 7.85%, the NPV of these flows is USD 95.390. At an
exchange rate of 6.00, this is equivalent to FRF 572.341.
For each USD 100 face value of the bond, you invested USD 95.00. This is equivalent to FRF 570. You therefore wish to receive a series of FRF cashflows, such that
there is a regular FRF cashflow in years 1 to 5, with an additional cashflow of FRF
570 in year 5. The NPV of these cashflows, discounting at 8.35% must be FRF
572.341. This can be solved using the TVM function on an HP calculator to give
the regular cashflow as FRF 48.187. Other profiles for the FRF cashflows could be
chosen which also have an NPV of FRF 572.341. This profile, however, provides
the par structure at which we are aiming.
The yield on the asset swap is therefore the yield derived from an investment
of FRF 570, a principal amount of FRF 570 returned at the end of 5 years and
an income stream of FRF 48.187 per year. This can be seen to be a yield of:
48.187
= 8.454%.
570
Date
Now
Year 1
Year 2
Year 3
Year 4
Year 5
NPV =
Bond
USD
– 95.00
+ 6.70
+ 6.70
+ 6.70
+ 6.70
+ 106.70
Swap
USD
FRF
– 6.70
– 6.70
– 6.70
– 6.70
– 106.70
+ 48.187
+ 48.187
+ 48.187
+ 48.187
+ 618.187
– 95.39
+ 572.341
Net cashflows
FRF
– 570.000
+ 48.187
+ 48.187
+ 48.187
+ 48.187
+ 618.187
217
Part 4 · Swaps and Options
EXERCISES
71. You have a USD 10 million borrowing on which you are paying 8.9% fixed
(annual money-market basis) and which has exactly 5 years left to run. All the
principal will be repaid at maturity.
The current 5-year dollar interest rate swap spread is quoted to you as 80 /
90 over treasuries. The current 5-year treasury yield is 9.0%. (US treasuries are
quoted on a semi-annual bond basis.)
You believe that interest rates are going to fall, and wish to swap the borrowing from fixed to floating. Without discounting all the cashflows precisely,
what will the resulting net LIBOR-related cost of the swapped borrowing be
approximately?
72. The 3-month USD cash rate and the futures prices for USD are as follows. The
first futures contract period begins exactly 3 months after spot.
3-month cash:
futures 3 v 6:
6 v 9:
9 v 12:
12 v 15:
15 v 18:
(91 days)
(91 days)
(91 days)
(92 days)
(91 days)
(91 days)
6.25%
93.41
92.84
92.63
92.38
92.10
a.
What are the zero-coupon swap rates (annual equivalent, bond basis) for each
quarterly maturity from 3 months up to 18 months, based on these prices?
b.
What should the 18-month par swap rate be on a quarterly money
market basis?
73. A year ago your sterling-based company issued a USD 100 million 4-year bond
with a 10% annual coupon, and converted the proceeds to sterling at 1.80. The
sterling/dollar exchange rate is now 1.55 and you wish to protect against any further currency loss by swapping the borrowing into sterling. A counterparty is
prepared to pay the outstanding USD cashflows on your bond valued at 9%
(annual bond basis), and receive equivalent sterling cashflows at 11%.
a.
What will your future cashflows be if you enter into such a swap?
b.
What would the cashflows be if, instead of using a swap, you used longdated foreign exchange to convert all your dollar liabilities into sterling? To
calculate the forward prices, assume that they are based on the following
money-market interest rates:
1 year
2 years
3 years
c.
218
USD
9.0%
8.5%
8.0%
GBP
14.0%
12.0%
10.0%
Which method would you prefer to use to hedge the dollar liabilities?
8 · Interest Rate and Currency Swaps
74. You issue a 5-year, 6.5% annual coupon bond for USD 10 million and swap it
into floating-rate CHF. The spot USD/CHF exchange rate is 1.50 and the current
swap rate is 6.8% fixed USD against 6-month CHF LIBOR. The swap matches
your USD flows exactly and achieves a regular floating-rate cost based on the
equivalent CHF amount borrowed with the same amount repaid at maturity.
Show the cashflows involved and calculate the all-in CHF floating-rate cost
you achieve, assuming all CHF cashflows can be discounted at 4.5% (annual)
and all USD cashflows at 6.8% (annual). Ignore all bond-issuing costs.
75. You have previously entered a currency swap to receive fixed-rate US dollars
at 8% (annually, 30/360 basis) based on USD 10 million (with USD 10 million
received at maturity) and pay floating-rate Deutschemarks at LIBOR (semiannually, ACT/360 basis) based on DEM 15 million (with DEM 15 million paid at
maturity). The swap terminates on 25 May 1999. It is now February 1998 and
the spot USD/DEM exchange rate is 1.6500. The last Deutschemark LIBOR
fixing was 5.3% for 25 November 1997. The discount factors to the remaining
payment dates are as follows. What is the mark-to-market value of the swap
now in dollars?
25 May 1998:
25 November 1998:
25 May 1999:
USD
0.9850
0.9580
0.9300
DEM
0.9880
0.9650
0.9400
76. You issue a 3-year fixed-rate US dollar bond at 7% (annual) with a bullet maturity. After all costs, you receive 99.00 from the issue. You swap the bond to
floating-rate dollars. You arrange the swap so that your net cashflows from the
swapped bond issue give you a par amount at the beginning, a regular LIBORrelated cost based on this par amount for 5 years, and the same par amount to
be repaid at maturity. The current par swap rate for 3 years is 7.5% (annual,
30/360 basis) against LIBOR (semi-annual, ACT/360). Assuming that this same
rate of 7.5% (annual) can be used as a rate of discount throughout, what all-in
floating-rate cost can you achieve above or below LIBOR?
219
■
■
■
“As with insurance premiums,
assuming that option sellers can
accurately assess the probability
of each possible outcome, their
total payments out on expiry of a
portfolio of options sold should
approximate to the premiums
received. Option pricing theory
therefore depends on assessing
these probabilities.”
220
9
Options
Overview
The ideas behind option pricing
Pricing models
OTC options vs. exchange-traded options
The Greek letters
Hedging with options
Some “packaged” options
Some trading strategies
Some less straightforward options
Exercises
221
Part 4 · Swaps and Options
OVERVIEW
Two sections in this chapter include some mathematical equations which
may seem rather more complex than those we have looked at so far – the sections on Black–Scholes and Greek Letters. These have been included for
completeness, and do not need to be considered in detail by most readers. We
have kept to the aim of this book, which is to be practical rather than to
frighten, and have therefore not shown here how to derive these formulas.
The interested reader will find thorough mathematical treatments of the subject in some of the books mentioned in the Bibliography.
An option is a contract whereby one party has the right to complete a
transaction in the future (with a previously agreed amount, date and price) if
he/she so chooses, but is not obliged to do so. The counterparty has no
choice: they must transact if the first party wishes and cannot otherwise. For
the first party, an option is therefore similar to a forward deal, with the difference that they can subsequently decide whether or not to fulfil the deal.
For the second party, an option is similar to a forward deal with the difference that they do not know whether or not they will be required to fulfil it.
Clearly, the contract will be fulfilled only if advantageous to the first party
and disadvantageous to the second party. In return for this flexibility, the
first party must pay a “premium” up-front to compensate the second party
for the latter’s additional risk.
For someone using an option as a hedge rather than as a trading instrument, it can be considered as a form of insurance. An insurance policy is not
called upon if circumstances are satisfactory. The insured person is willing to
pay an insurance premium, however, in order to be able to claim on the
insurance policy if circumstances are not satisfactory. An option as a hedge is
similar. If an option enables a hedger to buy something at a certain rate but it
turns out to be cheaper in the market than that rate, the hedger does not
need the option. If, however, it turns out to be more expensive than the
option rate, the hedger can “claim” on the option. The hedger thus has
“insurance protection” at the option rate, for which a premium is paid.
For the trader selling the option, the situation is similar to that of the
insurer – the trader is exposed to the risk of being obliged to deliver at the
agreed rate but only being able to cover the position in the market at a much
worse rate.
Options are available in a wide range of underlying instruments, including
currencies, interest rates, bonds and commodities.
Key Point
222
An option is a deal for forward delivery, where the buyer of the option
chooses whether the transaction will be consummated, and pays a
premium for this advantage
9 · Options
Basic terminology
The first party described above is the purchaser or holder of the option.
The second party (the seller of the option who receives the premium) is
called the writer of the option.
Terminology
To exercise an option is to use it, rather than allow it to expire unused at
maturity.
With a European option, the holder can only exercise the option at expiry.
With a 3-month option, for example, the holder can only choose at the
end of 3 months whether or not to exercise. With an American option, however, the holder can choose to exercise at any time between the purchase
of the option and expiry. European and American options are both available everywhere; the terms are technical rather than geographical.
The price agreed in the transaction – the strike price or strike rate – is not necessarily the same as the forward rate for the same future date, but is
chosen to suit the option buyer. If it is more advantageous than the forward rate to the option buyer, the option is referred to as in-the-money. If
it is less advantageous than the forward rate to the option buyer, it is outof-the-money. If the strike is the same as the forward rate, the option is
at-the-money (ATM). As the market moves after the option has been written, the option will move in- and out-of-the-money.
A put option is an option to sell something. A call option is an option to
buy something. The “something” which is being bought or sold is
referred to as the underlying. Thus in a bond option, the bond is the
underlying. In a USD/DEM option, the exchange rate is the underlying.
In a short-term interest rate option, the underlying is an FRA or an
interest rate futures contract.
It is always possible to exercise an in-the-money option at an immediate
profit or, in the case of a European option, to lock in a profit immediately by reversing it with a forward deal and exercising it later. The
locked-in profit – the difference between the strike price and the current
market price – is known as the intrinsic value of the option. The intrinsic
value of an out-of-the-money option is zero rather than negative. The
remaining part of the premium paid for the option above this intrinsic
value is known as the time value.
THE IDEAS BEHIND OPTION PRICING
The concepts
The pricing of an option depends on probability. In principle, ignoring bid
offer spreads, the premium paid to the writer should represent the buyer’s
223
Part 4 · Swaps and Options
expected profit on the option. The profit arises from the fact that the option
buyer is always entitled to exercise an option which expires in-the-money, and
simultaneously cover the position in the market at a better price. The buyer
will never be obliged to exercise the option at a loss. As with insurance premiums, assuming that option sellers can accurately assess the probability of each
possible outcome, the writer’s total payments out on expiry of a portfolio of
options sold should approximate to the premiums received. Option pricing
theory therefore depends on assessing these probabilities and deriving from
them an expected outcome, and hence a fair value for the premium.
The factors on which these probabilities depend are as follows:
• The strike price: the more advantageous the strike is to the buyer at the
•
•
•
time of pricing, the greater the probability of the option being exercised, at
a loss to the writer, and hence the greater the option premium.
Volatility: volatility is a measure of how much the price fluctuates. The
more volatile the price, the greater the probability that the option will
become of value to the buyer at some time. This measurement is formalized in option pricing theory as the annualized standard deviation of the
logarithm of relative price movements.
The maturity: the longer the maturity of the option, the greater the probability that it will become of value to the buyer at some time, because the
price has a longer time in which to fluctuate.
Interest rates: the premium represents the buyer’s expected profit when the
option is exercised, but is payable up-front and is therefore discounted to
a present value. The rate of discount therefore affects the premium to
some extent. The forward price – and hence the relationship between the
strike and the forward – is also affected by interest rate movements. Most
importantly, in the case of an option on a bond or other interest-rate
instrument, the interest rate also directly affects the underlying price.
Because currency options involve two commodities (that is, each currency)
rather than one, currency option prices can be expressed in various ways:
a. As a percentage of the base currency amount.
b. In terms of the base currency per unit of the base currency.
c. As a percentage of the variable currency amount.
d. In terms of the variable currency per unit of the variable currency.
e. In terms of the base currency per unit of the variable currency.
f. In terms of the variable currency per unit of the base currency.
Example 9.1
A call option on USD 1 million against DEM (or alternatively, a DEM put option
against USD) has a strike of 1.50, with a current spot rate of 1.40. The option premium in absolute terms is USD 10,000. This could be expressed as:
(
(a) 1.00% =
10,000
1,000,000
(b) 1 US cent per dollar
224
)
9 · Options
(
(c) 0.93% =
10,000 × 1.40
1,000,000 × 1.50
)
(d) 0.93 pfennigs per Deutschemark
(e) 0.67 cents per Deutschemark (= 0.93 ÷ 1.40)
(f) 1.4 pfennigs per dollar (= 1 cent × 1.40)
The most usual methods of quotation are (a) and (f).
Basic statistics
Arithmetic mean and standard deviation
The arithmetic mean (or “mean”) of a series of numbers is the average of the
numbers. If we have the following numbers:
83, 87, 82, 89, 88
then the mean of the numbers is:
(83 + 87 + 82 + 89 + 88)
= 85.8
5
The “standard deviation” of the same numbers is a measure of how spread
out the numbers are around this mean. If all the numbers are exactly the
same, the standard deviation would be zero. If the numbers are very spread
out, the standard deviation would be very high. The standard deviation is
defined as the square root of the “variance.” The variance in turn is the average of the squared difference between each number and the mean.
With the numbers above, we have the following:
Data
83
87
82
89
88
Difference
between data
and 85.8
–2.8
+1.2
–3.8
+3.2
+2.2
(Difference)2
7.84
1.44
14.44
10.24
4.84
Mean = 85.8
Total = 38.80
.
ei
ip
The variance is thus † = 7.76 and the standard deviation is 7.76 = 2.79.
The symbol µ is sometimes used for the mean, the symbol σ for the standard
deviation, and σ2 for the variance.
Calculation summary
Mean (µ) = sum of all the values divided by the number of values
Calculation
summary
Variance (σ2) = mean of (difference from mean)2
When estimating the variance from only a sample of the data rather than
all the data, divide by one less than the number of values used
Standard deviation (σ) =
variance
225
Part 4 · Swaps and Options
Probability density
The “probability density” of a series of numbers is a description of how
likely any one of them is to occur. Thus the probability density of the results
of throwing a die is q-¥ for each possible result. The probability density of the
heights of 100 adult men chosen at random will be relatively high for around
170 cm to 180 cm, and extremely low for less than 150 cm or more than 200
cm. The “shape” of the probability density therefore varies with the type of
results being considered.
A particular probability density which is used as an approximate description of many circumstances in life is known as the “normal” probability
function (see Figure 9.1):
Fig 9.1
Normal probability density function
0.5
Probability
0.4
0.3
0.2
0.1
0.0
–5
–4
–3
–2
–1
0
Data
1
2
3
4
5
If the probabilities are as shown in Figure 9.1, for example, a number less
than –3 or more than +3 is extremely unlikely, while a number between say
–1 and +1 is rather likely.
The normal probability function is not straightforward – the equation for
Figure 9.1 is:
probability density =
1
x2
2π e 2
This function is important here because it is used in option pricing.
A standard assumption used for pricing options is that movements in the logarithm of relative prices can be described by this function. By this we mean
current price
LN(previous price). If we are looking at daily price changes, for example, this
today’s price
means that a series of data such as LN(yesterday’s price) is expected to have a
normal probability density.
current price
days
This relative price change previous price is the same as (1 + i × year), where i is
the rate of return being earned on an investment in the asset. In
days
days
Chapter 1, we saw that LN(1 + i × year) is equal to r × year where r is the
continuously compounded rate of return. Therefore the quantity
current price
LN(previous price) which we are considering is in fact the continuously compounded return on the asset over the period.
226
9 · Options
Probability distribution
The “cumulative probability distribution” of a series of numbers is the probability that the result will be no greater than a particular number. Thus the
probability distribution for throwing the die is:
probability q-¥ that the number thrown will be 1
probability w-¥ that the number thrown will be 1 or 2
probability e-¥ that the number thrown will be 1, 2 or 3
probability r-¥ that the number thrown will be 1, 2, 3 or 4
probability t-¥ that the number thrown will be 1, 2, 3, 4 or 5
probability y-¥ that the number thrown will be 1, 2, 3, 4, 5 or 6
The normal probability function shown above has the probability distribution shown in Figure 9.2. With this particular probability distribution, for
example, there is a probability of around 85% that the outcome will be less
than or equal to 1.
Fig 9.2
Cumulative probability
Normal cumulative probability distribution
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
–5
–4
–3
–2
–1
0
Data
1
2
3
4
5
Calculating historic volatility
The volatility of an option is defined formally as the annualized standard
deviation of the logarithm of relative price movements. As we saw in the previous section, this is the standard deviation of the continuously compounded
return over a year.
Example 9.2
Given five daily price data for an exchange rate, the volatility is calculated as follows:
Day
Exchange
rate
1
2
3
4
5
1.8220
1.8345
1.8315
1.8350
1.8265
iert ) etc.
LN(œq..^∑∑π
0.00684
-0.00164
0.00191
-0.00464
Mean = 0.00062
Difference
from mean
0.00622
– 0.00226
0.00129
– 0.00526
(Difference)2
0.000039
0.000006
0.000002
0.000028
Total = 0.000074
227
Part 4 · Swaps and Options
Variance =
sum of (differences)2 0.000074
=
= 0.000025
(number of data – 1)
3
Standard deviation = variance = 0.00497
.
Volatility = standard deviation × frequency of data per year
= 0.00497 ×
252 = 7.9%
The frequency per year of the data in Example 9.2 assumes that weekends and
bank holidays are ignored for daily data. If “dummy” data are included for
these days, then the frequency per year is 365. If the data are weekly, the
annualized volatility is:
0.00497 × 52 = 3.6%
Note that we began with 4 data. Although there are 5 exchange rates, there
are only 4 relative price changes. In calculating the variance, we then divided
by 3, rather than 4 as suggested in the earlier section on standard deviation.
This is because when only a part of the historical data is used rather than all
possible data, a better estimate of the true variance is achieved by dividing by
(number of data – 1).
What we have calculated is the historic volatility – that is, the volatility of
actual recorded prices. When a dealer calculates an option price, he will not
in practice use a historic volatility exactly. Instead, he will use a blend of his
own forecast for volatility, the current general market estimate of volatility,
his own position, and recent actual experience of volatility.
The volatility which is used to calculate an option premium – either the price
quoted by a particular dealer or the current general market price – is known as
the “implied volatility,” or simply the “implied.” This is because, given the
pricing model, the price, and all the other factors, it is possible to work backwards to calculate what volatility is implied in that calculation. Implied
volatility therefore means current volatility as used by the market in its pricing.
Calculation
summary
Historic volatility =
standard deviation of LN(relative price movement) ×
frequency of data per year
PRICING MODELS
Black–Scholes
The most widely used pricing model for straightforward options was derived
by Fischer Black and Myron Scholes and is known as the Black–Scholes formula. This model depends on various assumptions:
• Future relative price changes are independent both of past changes and of
the current price.
• Volatility and interest rates both remain constant throughout the life of
228
the option. In practice, volatility and interest rates are not constant
throughout the option’s life. In the case of a bond option, for example,
this causes significant problems. First, volatility tends towards zero as the
9 · Options
•
•
bond approaches maturity, because its price must tend to par. Second, the
price of the bond itself is crucially dependent on interest rates, in a way
that, say, an exchange rate is not.
The probability distribution of relative price changes is lognormal. The assumption of a lognormal distribution implies a smaller probability of significant
deviations from the mean than is generally the case in practice. This is reflected
in how fat or thin the “tails” of the bell-shaped probability curve are and affects
the pricing of deep in-the-money and deep out-of-the-money options.
There are no transaction costs.
Based on these assumptions, the price of a European call option for one unit
of an asset which does not pay a dividend is:
Black-Scholes option-pricing formula for a non-dividend-paying asset
Calculation
summary
Call premium = spot price × N(d1) – strike price × N(d2) × e–rt
Put premium = –spot price × N(–d1) + strike price × N(–d2) × e–rt
= call premium + strike price × e–rt – spot price
where: d1
d2
=
=
spot × ert
strike
LN(
) + σ2t
2
σ t
spot × ert
strike
LN(
) – σ2t
2
σ t
t
= the time to expiry of the option expressed as a proportion
of a year (365 days)
σ
= the annualized volatility
r
= the continuously compounded interest rate
N(d) = the standardized normal cumulative probability distribution
One difficulty with the Black–Scholes formula is that the normal distribution function cannot be calculated precisely as a formula itself. Tables giving
values of the function are, however, widely available. Alternatively, it can be
very closely approximated – although the approximations are rather messy.
One such approximation is:
0.4361836
N(d) = 1 –
1 + 0.33267d
–
0.1201676
(1 + 0.33267d)2
d2
+
0.937298
(1 + 0.33267d)3
when d ≥ 0
2π e 2
and N(d) = 1 – N(–d)
when d < 0
In the case of a currency option, the Black–Scholes formula can be rewritten
slightly.
229
Part 4 · Swaps and Options
Calculation
summary
Black-Scholes formula for currency option
Call premium = (forward outright price × N(d1) – strike price × N(d2)) × e–rt
Put premium = (– forward outright price × N(–d1) + strike price
× N(–d2)) × e–rt
= call premium + (strike price – forward price) × e–rt
where: the option is a call on a unit of the base currency (that is, a put
on the variable currency) and the premium is expressed in units
of the variable currency.
d1=
d2=
LN(
forward
strike
) + σ2t
2
σ t
LN(
forward
strike
) – σ2t
2
σ t
r = the continuously compounded interest rate for the variable
currency.
The expressions ert and e–rt in the formulas above can be replaced by (1 + i × t) and
1
(1+ i × t) respectively, where i is the simple interest rate for the period rather than the
continuously compounded rate.
Example 9.3
What is the cost (expressed as a percentage of the USD amount) of a 91-day FRF
call against USD at a strike of 5.60? The spot rate is 5.75, the forward outright is
5.70, volatility is 9.0%, and the FRF 3-month interest rate is 5.0%.
We are calculating the price of a USD put. Using the Black–Scholes formula, with
the same notation as above:
r=
365
91
= 0.0504
× LN 1 + 0.05 ×
91
360
d1 =
(
+ 0.09
LN(5.70
5.60 )
0.09
d2 =
)
LN(5.70
– 0.09
5.60 )
0.09
2
91
× 365
2
= 0.4163
91
365
2
91
× 365
2
= 0.3714
91
365
91
put premium = (–5.70 × N(–0.4163) + 5.60 × N (–0.3714)) × e–0.0504× 365
= (–5.70 × 0.3386 + 5.60 × 0.3552) × 0.9875
= 0.0584
230
The cost is therefore 0.0584 FRF for each one dollar underlying the option. As a
percentage of the USD amount, this is:
0.0584
= 1.02%
5.75
9 · Options
Binomial trees
One way of building a model for option pricing is to simplify the assumptions to the possibility that the price of something may move up a certain
extent or down a certain extent in a particular time period. Suppose, for
example, that the price of a particular asset is now 1, and that the price
may rise by a multiplicative factor of 1.010000 or fall by a factor of
qœ..pppp
πœππ = 0.990099 each month. After two months, the price may have moved
along any of the following four routes, with three possible outcomes:
from 1 to 1.010000 and then to (1.010000 × 1.010000) = 1.020100
from 1 to 1.010000 and then to (1.010000 × 0.990099) = 1.000000
from 1 to 0.990099 and then to (0.990099 × 1.010000) = 1.000000
from 1 to 0.990099 and then to (0.990099 × 0.990099) = 0.980296
After three months, there are eight possible routes (up, up, up, or up, up, down,
or up, down, up, etc.) and four possible outcomes. A lattice of possible paths for
the price, known as a “binomial tree,” can be built up in this way. Depending on
the relative probabilities of an up movement or a down movement, we can calculate the expected outcome at the end. From this, we can assess the expected
value of an option to buy or sell the asset at the end, at any given strike price.
The first step therefore is to find the probabilities of up and down movements.
We can in fact calculate these probabilities if we know the rate of interest
which would be earned on a cash deposit – the “risk-free” rate of return. We
do this by equating the expected outcome of owning the asset to the known
outcome of the deposit, as follows. See below (“Risk free portfolio”) for a
justification for equating these two outcomes for this purpose.
Suppose that the probability of a move up in the asset price after one
month is p, and that the probability of a move down is (1 – p). Suppose also
that the current 1-month interest rate is 6 percent per annum.
Although we do not know what the asset price will be after one month,
the expected price can be expressed as:
p × 1.01 + (1 – p) × 0.990099 = 0.990099 + 0.019901 × p
As the interest rate is 6 percent, if we were to invest 1 in a risk-free deposit
for one month, we would expect after one month to receive a total of:
1
1 + 6% × 12 = 1.005
If this outcome is the same as investing in the asset, we have:
0.990099 + 0.019901 × p = 1.005
This gives:
p = 1.005 – 0.990099 = 0.748756
0.019901
We can thus calculate what is the probability of a move up or down, implied
by the current expected rate of return (the interest rate) and the size of the
possible movements up and down.
Now suppose that, based on this model, we wish to value a one-month
call option on 1 unit of the asset with a strike of 1.004.
There is a probability p = 0.748756 that the price will end at 1.01, in
which case the option will be worth 1.01 – 1.004 = 0.006. There is a proba231
Part 4 · Swaps and Options
bility (1 – p) = 0.251244 that the price will move down, in which case the
option will expire worthless.
p
1
1 × 1.01 = 1.01
with probability p = 0.748756
(1– p)
1 ÷ 1.01 = 0.990099
with probability (1– p) = 0.251244
The expected value of the option at maturity is therefore:
(0.748756 × 0.006) + (0.251244 × 0) = 0.004493
The present value of the option is therefore
0.004493 = 0.004470
(1 + 0.06 × 121 )
The price of the option is therefore 0.45%.
Example 9.4
With the same details as above, what is the value of a 2-month call option and a
3-month call option with the same strike of 1.004?
2 months
There is a probability of p × p = (0.748756)2 = 0.560636 that the price will be 1.01 ×
1.01 = 1.020100 at maturity, in which case the option will be worth 1.020100 –
1.004 = 0.0161.
There are two routes along the tree to reach a price of 1 again at the end of two
months – either up first then down again, or down first then up again. Therefore
there is a probability of 2 × p × (1 – p) = 2 × 0.748756 × 0.251244 = 0.376241 that
the price will be 1.01 x 0.990099 = 1 at maturity, in which case the option will
expire worthless.
There is a probability of (1 – p)2 = (0.251244)2 = 0.063124 that the price will be
0.990099 × 0.990099 = 0.980296 at maturity, in which case the option will
expire worthless.
p
1
1 × 1.01
p
(1– p)
1 ÷ 1.01
p
(1– p)
(1– p)
1 × 1.01 × 1.01 = 1.020100
with probability p × p = 0.560636
1 with probability 2 × p × (1– p) = 0.376241
1 ÷ 1.01 ÷ 1.01 = 0.980296
with probability (1– p) × (1– p) = 0.063124
The expected value of this option at maturity is therefore:
(0.560636 × 0.0161) + (0.376241 × 0) + (0.063124 × 0) = 0.009026
The present value of the option is therefore
0.009026
(1 + 0.06 × 121 )2
0.89% is therefore the price of this 2-month option.
232
= 0.008937
9 · Options
3 months
p
p
1
1 × 1.01
(1– p)
(1– p)
p
1 ÷ 1.01
1 × 1.01
× 1.01
p
(1– p)
p
1
(1– p)
1 ÷ 1.01
÷ 1.01
(1– p)
p
(1– p)
1 × 1.01 × 1.01 × 1.01 = 1.030301
with probability
p × p × p = 0.419779
1 × 1.01 = 1.010000
with probability
3 × p × p × (1– p) = 0.422569
1 ÷ 1.01 = 0.990099
with probability
3 × p × (1– p) × (1– p) = 0.141792
1 ÷ 1.01 ÷ 1.01 ÷ 1.01 = 0.970590
with probability
(1– p) × (1– p) × (1– p) = 0.015859
From the tree, we can see that the expected value of the option at maturity is:
(0.419779 x [1.030301 – 1.004]) + (0.422569 x [1.01 – 1.004])
+ (0.141792 x 0) + (0.015859 x 0) = 0.013576
The option price is therefore the present value of this expected outcome:
0.013576
(1 + 0.06 × 121 )3
= 1.34%
Risk-free portfolio
It may seem unreasonable, when calculating the probabilities of up and down
movements, to equate the expected outcome of investing in the asset with the
outcome of investing at a risk-free interest rate. It is possible to justify this,
however, by constructing an investment package which does have a known
outcome, as follows.
In the example above for a one-month option, we could sell a call option
on one unit of the asset for a premium of 0.004470. Suppose that at the same
time we buy 0.301492 units of the asset at the current price of 1. The net
cost of this investment package would be:
0.301492 – 0.004470 = 0.297022
If the price is 1.01 at the end of the month, the option would be exercised
against us, so that we would make a loss on the option of 1.01 – 1.004 =
0.006. The price of the asset we purchased would also have risen to 1.01,
however, so that the total value of our investment at the end of the month
would have become:
0.301492 × 1.01 – 0.006 = 0.298507
If the price is 0.990099 at the end of the month, however, the option would not
be exercised against us. The value of the asset we purchased would have fallen to
0.990099, so that the total value of our investment would have become:
0.301492 × 0.990099 = 0.298507
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Part 4 · Swaps and Options
In this way we have constructed a package – consisting of a short position in
one call option and a long position in 0.301492 units of the asset – which
has a known outcome equal to 0.298507 whether the price rises or falls. This
outcome represents an annual return on our investment, as expected for a
risk-free investment, of:
– 1) × 12 = 6%
( 0.298507
0.297022
1
We now need to consider how to construct such a package in the first place.
We need to calculate how much of the asset should be purchased initially in
order to make it risk-free. If the amount of asset purchased is A, the two possible outcomes are:
or
A × 1.01 – 0.006 (if the price rises)
A × 0.990099 (if the price falls)
If there is to be no risk, these two outcomes must be equal, so that:
A × 1.01 – 0.006 = A x 0.990099
Therefore:
A=
0.006
= 0.301492
1.01 – 0.990099
and the final outcome is therefore:
0.301492 × 0.990099 = 0.298507
If the price of the call option on one unit of the asset is C, we now know that
our initial investment in this package must be (0.301492 – C). If the rate of
return is 6 percent, we know therefore that:
(
)
(0.301492 – C) × 1 + 0.06 × 1 = 0.298507
12
This gives the cost of the option, as before, as:
0.301492 –
0.298507
= 0.004470
1 + 0.06 × 1
12
(
)
Comparison with Black–Scholes
It can be shown that for a given period to the option expiry, if we build a
binomial tree which has more and more branches, each of which is shorter
and shorter, the result eventually becomes the same as the result of the
Black–Scholes formula – as long as the possible up and down price movements are chosen appropriately.
In the example above, what is the volatility of the asset price? We have
two possible values for LN(relative price movements):
and
234
LN(1.01) = 0.00995 with probability 0.748756
LN(0.990099) = – 0.00995 with probability 0.251244
9 · Options
The mean of these values is:
0.00995 × 0.748756 – 0.00995 × 0.251244 = 0.00495
The variance is therefore:
(0.00995 – 0.00495)2 × 0.748756 + (-0.00995 – 0.00495)2 × 0.251244
= 0.000074
The standard deviation is therefore:
0.000074 = 0.008631
As the data are monthly, the volatility is:
0.008631 × 12 = 2.98%
If we now value the three-month option using the Black–Scholes formula,
we have:
call premium = 1 × N(d1) –
1.004 × N(d2)
(1 + 0.06 × 121 ) 3
where:
(
)
1 3
LN (1+ 0.06 × 12) + (0.0298)
d1 =
1.004
)
1 3
LN (1+ 0.06 × 12) – (0.0298)
d1 =
1.004
0.0298 ×
× 12
2
× 12
3
12
0.0298 ×
(
3
2
2
3
2
3
12
This gives:
call premium = N(0.7437) – 0.9891 × N(0.7288)
= 0.7715 – 0.9891 × 0.7669 = 0.0130 = 1.30%
This option price of 1.30 percent calculated using the Black–Scholes formula
is close to the binomial model’s result of 1.34 percent.
In the example above, we assume that we know in advance the possible up
and down price movements. In practice, when using a binomial tree to estimate an option price, we need to choose these possible price movements in
such a way as to arrive at a result similar to the Black–Scholes model.
In order for the answers from the two models to converge as the number
of branches increases, the possible binomial up and down movements in the
price must be chosen to suit the parameters assumed by the Black–Scholes
model. One possible way of doing this is to choose them as follows:
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Part 4 · Swaps and Options
t
n
u = eσ
d=1
u
1
(1 + i × t) n – d
p=
u–d
where:
t
n
σ
u
d
i
= time to expiry expressed in years
= number of periods in the binomial tree
= volatility
= multiplicative up movement
= multiplicative down movement
= interest rate per annum to expiry
Put / call relationship, synthetic forwards and risk reversal
Suppose that I pay a premium of C to buy a European call option with a strike
price of K for an asset which pays no dividends. Suppose that at the same time
I receive a premium P to sell a put option on the same asset, also with a strike
of K. Third, suppose that I also sell the asset for forward delivery at the current
forward price F. If the asset price is above K at expiry, I will exercise my call
option at K. If it is below K at maturity, my counterparty will exercise the put
option which I have sold to him. Either way, I buy the asset at a price K.
However, I also sell the asset at price F, because of the forward deal. I therefore have a profit (F – K). On the basis that “free profits” are not available,
this must offset my net payment (C – P). However, (F – K) is received / paid at
maturity while (C – P) is paid / received up-front. Therefore:
Calculation
summary
Call premium – put premium =
(forward price – strike price) discounted to a present value
Expressed in terms of the spot price rather than the forward price, this is:
Calculation
summary
Call premium – put premium =
spot price – (strike price discounted to a present value)
If the strike price is set equal to the forward price, (C – P) must be zero.
Therefore, with an option struck at the forward price (at-the-money), the put
and call premiums are equal. This is the “put / call parity”. This relationship
explains the formulas given for the put premium in the section on
Black–Scholes.
This relationship is also important because it is related to the creation of
synthetic positions. From the above analysis, it can be seen that for any strike
price K, it is true that:
sell forward plus buy call plus sell put = 0
This is the same as saying:
236
9 · Options
buy forward = buy call plus sell put
or
sell forward = sell call plus buy put
These two relationships show that a synthetic forward deal can be created
from two option deals.
Synthetic forwards
Key Point
Buying a call and selling a put at the same strike creates a synthetic forward purchase – and vice versa
The relationship can also be expressed as follows:
buy call = buy put plus buy forward
sell call = sell put plus sell forward
buy put = buy call plus sell forward
sell put = sell call plus buy forward
Thus, for example, a trader can either buy a call at a particular strike or, if
priced more efficiently, he can buy a put at the same strike and buy forward
simultaneously. Viewed from a different standpoint, this is known as “risk
reversal.” If, for example, a trader already has a position where he is long of
a put, he can reverse this position to become effectively long of a call instead,
by buying forward.
Risk reversal
Key Point
A long or short position in a call can be reversed to the same position in
a put by selling or buying forward – and vice versa
OTC OPTIONS VS. EXCHANGE-TRADED OPTIONS
The difference between OTC options and those traded on an exchange is
parallel to the difference between OTC instruments such as forwards and
exchange-traded futures. In the case of an exchange-traded option, the
underlying “commodity” may be the corresponding futures contract. Thus
on LIFFE, if an interest-rate option is exercised, the option buyer receives a
LIFFE interest rate futures contract. On the Philadelphia Currency Options
Exchange, on the other hand, most currency options are deliverable into a
cash currency exchange. Exchange-traded options may be either European or
American. On LIFFE, for example, most options are American, although
there is also a European option on the FTSE 100 index. On the IMM,
options are American; on the Philadelphia Exchange, there is a range of both
American and European currency options.
One significant difference which can arise between OTC and exchangetraded options concerns the premium payment. On the IMM and other
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Part 4 · Swaps and Options
exchanges the option buyer pays a premium up-front as with an OTC
option, but pays no variation margin. On LIFFE, however, the premium is
effectively paid via the variation margin. The variation margin paid or
received each day represents the change in value of the option. If, for example, an option expires worthless at maturity, the variation margin payments
made over the life of the option total the change in value from the original
premium to zero. There is therefore no premium payable at the beginning.
On LIFFE the exercise of a call (or put) option on a futures position
simply causes a long (or short) futures position to be assigned to the option
purchaser and a corresponding short (or long) position to be assigned to the
option writer. Positions are assigned at the option exercise price and then
marked-to-market in the usual way.
Once an option has been exercised, its price is effectively zero. Therefore,
the difference between its market price at the time of exercise and zero is
paid as settlement margin. Thus the full option premium will then have been
paid partly as variation margin during the life of the option and partly as settlement margin.
Strike prices for OTC options can be set at any level agreed between the
two parties – generally at the buyer’s request. Exchanges, however, set a
series of strikes, spaced at regular intervals, which are extended as the underlying price moves up and down.
The tick values on exchange-traded options are not always straightforward. US T-bonds and T-bond futures, for example, are priced in multiples
q∑. Options on T-bonds, however, are priced in multiples of ¥_
q®.
of ´_
THE GREEK LETTERS
In principle, an option writer could sell options without hedging his position. If
the premiums received accurately reflect the expected payouts at expiry, there
is theoretically no profit or loss on average. This is analogous to an insurance
company not reinsuring its business. In practice, however, the risk that any one
option may move sharply in-the-money makes this too dangerous. In order to
manage a portfolio of options, therefore, the option dealer must know how the
value of the options he has sold and bought will vary with changes in the various factors affecting their price, so that he can hedge the options.
Delta
An option’s delta (∆) measures how the option’s value (which is the same as
its current premium) varies with changes in the underlying price:
∆=
change in option’s value
change in underlying’s value
Mathematically, the delta is the partial derivative of the option premium
with respect to the underlying, ∂C or ∂P (where C is the call premium, P is
∂S
∂S
238
9 · Options
the put premium and S is the price of the underlying). Based on the Black–
Scholes formula given earlier, and with the same notation, the delta can be
shown to be N(d1) for a call and –N(–d1) for a put. If an option has a delta
of 0.7 (or 70%), for example, a $100 increase in the value of the underlying
will cause a $70 increase in the value of the option.
For a call option which is deep out-of-the-money, the premium will increase
very little as the underlying improves – essentially the option will remain worth
almost zero. For an option deep in-the-money, an improvement in the underlying will be reflected completely in the call premium. The delta is therefore close
to zero for deep out-of-the-money call options, 0.5 at-the-money, and close to
1 for deep in-the-money call options. For put options, delta is close to zero
deep out-of-the-money, –0.5 at-the-money, and close to -1 deep in-the-money.
Consider, for example, a call option on an asset with a strike price of 99.
When the current price is 99, the option will have a certain premium value C.
If the current price rises to 99.5, the option will have a higher value because
it could be exercised for a 0.5 profit if the current price remains at 99.5.
However, there is still a probability of approximately 50 percent that the
price will fall and the option will expire worthless. The premium increase is
therefore only approximately 50 percent of the underlying increase.
When an option trader wishes to hedge an option he has written, he has
several choices:
• Buy an exactly matching option.
• Buy or sell the underlying. In this case, the trader will buy or sell enough
of the underlying so that if the price changes he will make a profit or loss
which exactly offsets the loss or profit on the option position. In the
example above, he would buy the underlying asset to the extent of 50 percent of the option amount. In this way, if the price rises from 99 to, say,
100, he will make a profit of 1 on half the amount of the option. This
would offset a loss on the option position of 0.5 on the whole amount. In
general, the amount of the hedge is equal to:
delta × the notional amount of the option.
•
This is known as “delta hedging” and demonstrates the importance of
knowing the delta.
Buy or sell another instrument with the same (but opposite) value for
(delta × notional amount), so that again any change in the underlying
price gives rise to a change in the hedge value which exactly offsets the
change in the option value. In the example above, such a hedge might be
the purchase of an option with a different strike price – say, a larger
amount of an option on the same asset which is slightly out-of-the-money
(and hence has a smaller delta).
If a trader is short of a call (as in this example) or long of a put, he has
a negative delta and needs to buy the underlying in order to hedge. If he is
long of a call or short of a put, he has a positive delta and needs to sell the
underlying in order to hedge.
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Part 4 · Swaps and Options
Key Point
Delta hedging an option can be achieved by buying or selling the correct
amount of the underlying so that any change in the option’s P & L is
offset by a change in the underlying position’s P & L
Gamma
One problem with delta hedging an option or portfolio of options is that the
delta itself changes as the underlying price changes, so that although a portfolio may be hedged, or “delta neutral” at one moment, it may not be so the
next moment. An option’s gamma (Γ) measures how much the delta changes
with changes in the underlying price:
Γ=
change in delta
.
change in price
Mathematically, this is the second partial derivative of the premium with
∂2P
∂2C
respect to the underlying price,
or 2 . Based on the Black-Scholes for2
∂S
∂S
1
mula, Γ can be shown to be
for a call or a put.
d12
2
Sσ 2πt e
As already discussed, the delta does not change rapidly when an option is
deep out-of-the-money (the delta remains close to zero) or when an option is
deep in-the-money (the delta remains close to 1 or -1), so that gamma is very
small. When an option is close to the money, however, the delta changes
rapidly, and the gamma of a call is at its greatest slightly out-of-the-money.
Gamma is positive for long option positions, both calls and puts, and negative for short calls and short puts.
Ideally, a trader who wishes to be fully hedged would like to be gammaneutral – that is, to have a portfolio of options where the delta does not
change at all.
Suppose, for example, that an option portfolio is currently delta-neutral,
but has a portfolio gamma (= gamma × portfolio size) of -60. A particular
option which could be used to hedge this has a delta of 0.5 and a gamma of
0.6. The gamma of the portfolio could be reduced to zero by adding a long
yp.¥ = 100 units of the option. However, the delta of the portfolio
position of π–
would now be 100 × 0.5 = 50. It is therefore necessary to superimpose on
this, for example, a further hedge of a short position of 50 in the underlying
– to reduce the delta back to zero. This will not affect the portfolio’s gamma,
because the underlying has a delta of 1 but a gamma of zero. The portfolio
would still need to be hedged dynamically – because the gamma and the delta
will change as the underlying moves – but it would be less vulnerable.
Vega
An option’s vega (or epsilon (ε), eta (η), lambda (λ) or kappa (κ)) measures how
much an option’s value changes with changes in the volatility of the underlying:
240
9 · Options
vega =
change in option’s value
change in volatility
Mathematically, this is the partial derivative of the option premium with
∂C
∂P
respect to volatility,
or
. Based on the Black-Scholes formula, this is
∂σ
∂σ
t
2π
S
d12
2
for a call or a put.
e
Vega is at its highest when an option is at-the-money and falls as the
market and strike prices diverge. Options closer to expiration have a lower
vega than those with more time to run. Positions with positive vega will generally have positive gamma. To be long vega (to have a positive vega) is
achieved by purchasing either put or call options.
Theta
An option’s theta (Θ) measures how much an option’s value changes with
changes in the time to maturity:
theta (Θ) = –
change in option’s value
change in time
Mathematically, this is –
∂C
∂P
or –
. Based on the Black–Scholes formula, this is
∂t
∂t
d
d
– Sσ e– 2 – Kre–rtN(d2) for a call or – Sσ e– 2 + Kre–rtN(–d2)for a
2 2πt
2 2πt
2
1
2
1
put, where K is the strike price.
Theta is negative for a long option position and positive for a short option
position. The more the market and strike prices diverge, the less effect time
has on an option’s price and hence the smaller the theta. Positive theta is generally associated with negative gamma and vice versa.
Rho
An option’s rho (ρ) measures how much an option’s value changes with
changes in interest rates:
rho (ρ) =
change in option’s value
change in interest rate
∂C
∂P
or
. Based on the Black–Scholes formula, this
∂r
∂r
is Kte–rt N(d2) for a call or – Kte–rtN(–d2) for a put.
Rho tends to increase with maturity.
Mathematically, this is
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Part 4 · Swaps and Options
Calculation
summary
Based on the Black–Scholes formula
Delta (∆) = N(d1) for a call
or –N(–d1) for a put
1
Gamma (Γ) =
d12
Sσ 2πt e 2
Vega =
t
2π
S
d12
e2
2
Theta (Θ) = –
Sσ e– d12 – Kre–rtN(d ) for a call
2
2 2πt
2
or –
Sσ e– d12 + Kre–rtN(–d ) for a put
2
2 2πt
Rho (ρ) = Kte–rt N(d2) for a call
or – Kte–rtN(–d2) for a put
where:
S = spot price
K = strike price
HEDGING WITH OPTIONS
Comparison with forwards
A company with a long peseta position which it wishes to hedge against
guilders has three basic choices. It can do nothing and remain unhedged, it
can sell the pesetas forward, or it can buy a peseta put option. In general, the
option will never provide the best outcome because of the premium cost: if
the peseta falls, the company would be better selling forward; if the peseta
rises, the company would be better remaining unhedged. On the other hand,
the option provides the safest overall result because it protects against a
peseta fall while preserving opportunity gain if the peseta rises. Essentially, if
the company firmly believes the peseta will fall, it should sell forward; if the
company firmly believes the peseta will rise, it should do nothing; if the company believes the peseta will rise but cannot afford to be wrong, it should
buy a peseta put option. The outcomes of the three possibilities are as follows. Figure 9.3 shows the effective net outcome (in terms of the exchange
rate achieved net of the option premium cost) for a hedger with an underlying position. It is important to note that, unlike the subsequent figures in this
chapter, it is not a profit / loss profile on a “naked” position with no underlying exposure.
242
9 · Options
Hedging a long pesta exposure
Exchange rate achieved
Do nothing
Fig 9.3
buy peseta put
Sell pesetas forward
Exchange rate at maturity
Interest rate guarantees
A parallel situation arises in interest rate hedging. A company with a shortterm borrowing rollover in the future also has three basic choices. It can
remain unhedged, buy an FRA or buy or sell an option on an FRA (an “interest rate guarantee” or IRG). A currency option is an option to buy an agreed
amount of one currency against another currency at an agreed exchange rate
on an agreed date. An IRG is the interest rate equivalent of this.
An IRG is effectively an option to buy or sell an agreed amount of an FRA
in one particular currency at an agreed rate for an agreed maturity and on an
agreed delivery date. An interest rate guarantee can therefore fix the maximum cost on a future borrowing (or the minimum return on a future
deposit). The IRG does not entail an actual borrowing or deposit. Like a
futures contract, it is a “contract for differences”: the difference between the
strike rate and the actual rate at settlement is paid or received.
An IRG can be either a “borrower’s option” or a “lender’s option.” This
terminology may be safer than thinking in terms of “call” or “put” because a
call on an FRA is equivalent to a put on an interest rate futures contract.
Caps and floors
A cap or ceiling is a series of IRGs (borrower’s options) generally at the same
strike, purchased together to secure a series of borrowing rollovers. Suppose,
for example, that a borrower has a 5-year loan which he rolls over each 3
months at the 3-month LIBOR then current. He can buy a 5-year cap which
will put a maximum cost on each of the rollovers. Whenever the rollover rate
exceeds the cap strike rate, he receives the difference. Whenever the cap
strike rate exceeds the rollover rate, nothing is paid or received.
A floor is similarly a series of IRGs (lender’s options) purchased to secure
a series of deposits, by putting a minimum return on each rollover.
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Part 4 · Swaps and Options
SOME “PACKAGED” OPTIONS
Various OTC option-based products are offered by banks to their customers,
some of which can be constructed from straightforward options. The
common products available are as follows.
Range forward (or collar, cylinder, tunnel or corridor)
A straightforward option provides a fixed worst-case level at which the customer can deal, but allows him to deal at the market rate if this turns out
better. A range forward allows the customer to deal at a better market rate
only up to a certain level. Beyond that level, the customer must deal at
another fixed best-case level. In return for this reduced opportunity, the customer pays a lower premium for the option. Indeed the premium can be zero
(a zero-cost option) or even negative.
Such an arrangement can be constructed by buying one option (for example, a USD put option) and selling another (in this case a USD call option).
The premium earned from the second option offsets the premium paid on the
first option, either partly or (in the case of a zero-cost option) completely.
The obligation to deal at the strike rate of the second option, if the counterparty wishes, determines the best-case level. Setting the two strike rates
determines the net premium. Alternatively, setting the size of the net premium and one of the strike rates determines the other strike rate.
There is generally a technical difference between a range forward and a
collar. With a range forward, the customer is usually obliged to deal with the
bank. If neither of the range limits is reached (i.e. neither option is exercised)
at expiry, the customer must deal at the spot rate with the bank. With a
collar, the customer is not obliged to deal with any particular bank if neither
option is exercised. The term “range forward” usually applies to a deal with
a single future date, but in general a collar can be applied to any underlying
instrument. It is often used, for example, to describe the simultaneous purchase of a cap and sale of a floor.
Break forward (or forward with optional exit)
A break forward is a forward deal at a fixed rate (the worst-case level) with
another “break” level at which the customer may reverse the forward deal if
he/she chooses. For example, a break forward to sell USD at 1.52 with a
break at 1.55 obliges the customer to sell USD at 1.52 but allows him/her to
buy USD back at 1.55 if he/she chooses. If the USD strengthens to 1.61, for
example, the customer may buy the USD back again at 1.55 and sell them in
the market at 1.61 – an all-in effective rate of 1.58 (= 1.52 – 1.55 + 1.61).
A break forward has exactly the same profit / loss profile as a straightforward option, because it is in fact a straightforward option with deferred
payment of the premium. The fixed rate and break rates are set as follows.
Suppose that the forward rate for selling USD against DEM is currently 1.56
244
9 · Options
and the customer asks for a fixed rate of 1.52 as above. The bank calculates
what strike rate would be necessary on a USD put option so that the strike
rate less the future value of the premium is 1.52. This strike rate then
becomes the break rate.
Calculating the necessary strike rate can be done conveniently using the
put / call parity. As before, if C is the call premium and P is the put premium:
C – P = (forward – strike) discounted to a present value
or
strike – P* = forward – C* where P* and C* are the future values of P
and C
If the fixed rate set in the transaction is 1.52, this must represent the true
strike rate adjusted for the deferred put premium. In other words:
strike – P* = 1.52
From the put / call relationship, it follows that:
forward – C* = 1.52
Since the forward rate is 1.56, it follows that:
C* = 1.56 – 1.52 = 0.04
The call premium is therefore the present value of 0.04. This then determines
the true strike rate behind the deal, which is used as the break level.
Participation forward
A participation forward provides a worst-case level in the same way as an
option. If the customer wishes not to deal at this level because the market
level is better, he/she shares the benefit with the bank. For example, a participation forward to sell USD at 1.50 with a participation rate of 70
percent provides a worst-case level of 1.50. If the market rate is 1.60, the
customer receives 70 percent of the 0.10 benefit – i.e. 0.07 – and sells USD
at 1.57. There is no premium to pay for a participation forward, but there
is a potential 30 percent loss of advantage compared with a straightforward option.
A participation forward can be constructed by buying an option (in this
case a USD put option) and selling a smaller amount of an opposite option
(in this case a USD call option) at the same strike rate.
Setting the strike rates of the two options determines the two premiums. In
order for the total net premium to be zero, this then sets the amount of the
second option which must be sold, and hence the participation rate.
Alternatively, setting the participation rate will determine the strike rate for
the options which will result in a net zero premium.
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Part 4 · Swaps and Options
SOME TRADING STRATEGIES
Calls and puts
The most basic trading strategies are the purchase or sale of a call or a put.
The purchase of either gives rise to limited potential loss (the premium paid)
and almost unlimited potential profit. The sale of either gives the reverse.
Assuming that the price of the underlying can only fall as far as zero, the
potential profit from holding a put (or the loss from writing a put) is not
actually unlimited. The profit / loss profile can be illustrated as shown in
Figures 9.4 – 9.7.
Fig 9.4
Call purchase
Profit
buy call
0
Price
Loss
Fig 9.5
Put purchase
Profit
0
Price
buy put
Loss
246
9 · Options
Fig 9.6
Call sale
Profit
0
Price
sell call
Loss
Fig 9.7
Put sale
Profit
sell put
0
Price
Loss
Covered calls and puts
To sell a call or put as above without any underlying exposure is to write a
“naked” option. A “covered” call or put arises when the writer has an offsetting
position in the underlying – a long position in the underlying to offset the selling
of a call, or a short position in the underlying to offset the selling of a put.
Sale of a covered call can, for example, be used by a fund manager to
increase income by receiving option premium. It would be used for a security
he is willing to sell only if the underlying goes up sufficiently for the option
to be exercised. Generally, covered call writers would undertake the strategy
only if they thought implied volatility was too high. The lower the volatility,
the less the covered call writer gains in return for giving up potential profit in
the underlying. It provides protection against potential loss only to the extent
that the option premium offsets a market downturn.
A covered put can be used by a fund manager who is holding cash because
he has shorted securities, to increase income by receiving option premium.
Covered put writing can also be used as a way of target buying: if an investor
has a target price at which he wants to buy, he can set the strike price of the
option at that level and receive option premium meanwhile to increase the
247
Part 4 · Swaps and Options
yield of the asset. Investors may also sell covered puts if markets have fallen
rapidly but seem to have bottomed, because of the high volatility typically
received on the option in such market conditions.
Fig 9.8
Covered call sale
Profit
own underlying
0
Price
sell call
Loss
Fig 9.9
Covered put sale
Profit
sell put
0
Price
short underlying
Loss
Spread
Spreads involve the simultaneous purchase and sale of two different calls, or of
two different puts. A long call spread is the purchase of a call at one strike
price, offset by the simultaneous sale of a call at another strike price less in-themoney (or more out-of-the-money) than the first. This limits the potential gain
if the underlying goes up, but the premium received from selling the second call
partly finances the purchase of the first call. A call spread may also be advantageous if the purchaser thinks there is only limited upside in the underlying. A
put spread is similarly the simultaneous purchase of a put at one strike price,
offset by the simultaneous sale of a put less in-the-money (or more out-of-themoney) than the first – used if the purchaser thinks there is limited downside
for the underlying. To short a spread is the reverse. (See Figures 9.10–9.13.)
248
9 · Options
Fig 9.10
Call spread purchase
Profit
buy call
0
Price
sell call
Loss
Fig 9.11
Put spread purchase
Profit
sell put
0
Price
buy put
Loss
Fig 9.12
Call spread sale
Profit
buy call
0
Price
sell call
Loss
A bull spread is either the purchase of a call spread or the sale of a put
spread. A bear spread is either the sale of a call spread or the purchase of a
put spread.
249
Part 4 · Swaps and Options
Fig 9.13
Put spread sale
Profit
sell put
0
Price
buy put
Loss
A calendar spread is the purchase of a call (or put) and the simultaneous sale
of a call (or put) with the same strike price but a different maturity. For
example, if one-month volatility is high and one-year volatility low, a trader
might buy one-year options and sell one-month options, thereby selling
short-term volatility and buying long-term volatility. If short-term volatility
falls relative to long-term volatility, the strategy can be reversed at a profit.
Spreads constructed from options with the same maturity but different
strikes are sometimes known as “vertical” spreads, while calendar spreads
are “horizontal” spreads. A spread constructed from both different strikes
and different maturities is a “diagonal” spread.
Straddle
To go long of a straddle is to buy both a put and a call at the same strike
price. In return for paying two premiums, the buyer benefits if the underlying
moves far enough in either direction. It is a trade which expects increased
volatility. The seller of a straddle assumes unlimited risk in both directions
but receives a double premium and benefits if volatility is low. (See Figures
9.14 and 9.15.)
Fig 9.14
Straddle purchase
Profit
0
Loss
250
buy put
buy call
Price
9 · Options
Fig 9.15
Straddle sale
Profit
sell put
0
Loss
Price
sell call
Strangle
A strangle is similar to a straddle but the premiums are reduced by setting
the two strike prices apart – generally each strike will be out-of-the-money.
Profits are only generated on a long strangle position if the underlying moves
significantly. (See Figures 9.16 and 9.17)
Fig 9.16
Strangle purchase
Profit
buy call
0
Price
buy put
Loss
Fig 9.17
Strangle sale
Profit
sell put
0
Price
sell call
Loss
251
Part 4 · Swaps and Options
With combination strategies such as straddles and strangles, a “top” combination is one such as a straddle sale or a strangle sale which has a top limit to
its profitability and a “bottom” combination is the reverse, such as a straddle
purchase or a strangle purchase.
SOME LESS STRAIGHTFORWARD OPTIONS
We conclude, by way of illustration, with a selection of a few of the less
straightforward option types available.
Average rate option (or Asian option)
This is a cash-settled option, paying the buyer the difference (if positive)
between the strike and the average of the underlying over an agreed period.
The volatility of the underlying’s average is less than the volatility of the
underlying itself, so that the option cost is reduced.
Average strike option
Also cheaper than a straightforward option, this sets the strike to be the average of the underlying over a period, which is then compared with the actual
underlying rate at expiry.
Barrier option
A barrier option is one which is either activated (a “knock-in” option) or cancelled (a “knock-out” option) if the underlying reaches a certain trigger level
during the option’s life. For example, an “up-and-in” option becomes active if
the underlying rate moves up to a certain agreed level; if that level is not
reached, the option never becomes active, regardless of the strike rate. “Upand-out”, “down-and-in” and “down-and-out” options are defined
analogously. The circumstances in which the writer will be required to pay out
on a barrier option are more restricted, so the option is cheaper.
Binary option (or digital option)
A binary option has an “all or nothing” profit / loss profile. If the option
expires in-the-money, the buyer receives a fixed payout regardless of how far
the underlying has moved beyond the strike rate. A “one touch” binary
option pays out if the strike is reached at any time during the option’s life.
Compound option
An option on an option.
Contingent option
This is an option where the buyer pays no premium unless the option expires
in-the-money. If it does expire in-the-money, however, the buyer must then
pay the premium. The cost is higher than for a straightforward option.
252
9 · Options
Quanto option (or guaranteed exchange rate option)
A quanto option is one where the underlying is denominated in one currency
but payable in another at a fixed exchange rate.
Swaption
A swaption is an option on a swap. Exercising the option delivers the agreed
swap from the time of exercise onwards.
253
Part 4 · Swaps and Options
EXERCISES
77. What is the estimated annualized volatility of the USD/DEM exchange rate,
based on the following daily data, assuming the usual lognormal probability
distribution for relative price changes and 252 days in a year?
Day 1
Day 2
Day 3
Day 4
Day 5
Day 6
Day 7
Day 8
Day 9
Day 10
1.6320
1.6410
1.6350
1.6390
1.6280
1.6300
1.6250
1.6200
1.6280
1.6200
78. A 6-month (182 days) FRF call option against USD at a strike of 5.6000 costs
1.5% of the USD amount. What should a FRF put cost at the same strike rate?
USD/FRF spot:
USD/FRF 6-month outright:
USD 6-month LIBOR:
FRF 6-month LIBOR:
5.7550
5.7000
7%
5%
79. Construct a three-step binomial tree to calculate a price for a 3-month put
option on an asset at a strike of 101. The current price is 100. At each step,
the price either rises or falls by a factor of 2% (that is either multiplied by 1.02
or divided by 1.02). The risk-free interest rate is 12% per annum.
254
Part 5
Practice ACI Exam,
Hints and Answers
255
10
A Complete Practice
ACI Exam
257
Part 5 · Practice ACI Exam, Hints and Answers
The following pages contain a full exam, laid out similarly to the Financial
Calculations exam currently set as part of the ACI series of exams leading to fellowship of the ACI.
If you are serious about taking the ACI’s exam, we recommend that you work
through this practice version, and would like to make the following suggestions.
Familiarize yourself with the material throughout the book first and work through the
examples and worked answers to the exercises.
Try to work through the practice exam under ‘exam conditions.’ The exam lasts
2 hours and is in two parts:
•
•
Part 1: 30 minutes; around twelve short questions; 20 points available
Part 2: 2 hours; four exercises each containing several questions; 80 points
available
Use of a Hewlett Packard calculator – preferably a HP17BII or HP19BII – in the
exam is expected.
Chapter 11 includes answers to the exam.
Good luck!
258
10 · A Complete Practice ACI Exam
ACI FINANCIAL CALCULATIONS EXAM
•
•
•
A total of 100 points is available. The pass mark is 50 points; a distinction is
awarded for 80 points or more.
All dates are shown using the European date convention; that is, 12 April 1999
would be written as 12/04/99.
Programmable calculators such as a Hewlett Packard HP17BII or HP19BII
are allowed and recommended. Candidates are allowed to have their own
programs stored in the calculator. In Part 2 of the exam, intermediate calculations must be shown and correct answers without intermediate calculations
will earn no points at all.
PART 1
30 MINUTES
20 POINTS AVAILABLE
Please answer ALL the questions.
1.
You buy a 20-year annuity with a semi-annual yield of 10.5% (bond basis). How
much must you invest in the annuity now to receive 50,000 each six months?
2.
Give a formula, on a coupon date, for the value of a bond which pays a 7%
annual coupon and has 3 years left to maturity.
3.
You deposit 10 million for 5 years. It accumulates interest at 7% (bond basis)
paid semi-annually for 2 years, then 7.5% paid quarterly for the next 3 years.
The interest is automatically added to the capital at each payment date. What
is the total accumulated value at the end of 5 years?
4.
Calculate the 3 v 9 forward-forward rate, given the following rates quoted on
an ACT/360 basis. Show the formula as well as the result.
3 months (92 days): 9.00%
9 months (275 days): 9.00%
How would you deposit your money, if you believe that the 6-month deposit
rate available to you in 3 months’ time will be 8.90%?
5.
A three-month (91 days) DEM call option against GBP costs 1.0% of the GBP
amount at a strike of 2.60. What should a DEM put cost at the same strike?
GBP/DEM spot:
3-month outright:
3-month GBP LIBOR:
3-month DEM LIBOR:
2.6760
2.6500
8% (ACT/365)
4% (ACT/360)
6.
A 1-year interest rate is quoted as 8.35% (ACT/365) with all the interest paid at
maturity. What would the equivalent quotation be with interest paid (a) semiannually; (b) daily?
7.
What is the price on a coupon date of a 15-year bond, with a semi-annual
coupon of 10%, yielding 10.2%?
259
Part 5 · Practice ACI Exam, Hints and Answers
8.
You place £1 million on deposit for 1 year at 6.2% (ACT/365). What total value
will you have accumulated at the end of the year if the interest is paid quarterly
and can be reinvested at 6.0% also paid quarterly?
9.
The rate for a 57-day deposit is quoted as 8.5% (ACT/360). What is the effective rate on an ACT/365 basis?
10. Which of the following provides the best return for an investor considering a
182-day investment?
a.
b.
c.
d.
7.50% yield quoted on an ACT/365 basis
7.42% yield quoted on an ACT/360 basis
7.21% discount rate quoted on an ACT/365 basis
7.18% discount rate quoted on an ACT/360 basis
11. What is the 12-month interest rate (ACT/360 basis) implied by the following
rates (all ACT/360)?
3 months (91 days):
FRA 3 v 6 (92 days):
FRA 6 v 9 (91 days):
FRA 9 v 12 (91 days):
6.5%
6.6%
6.8%
7.0%
12. Are the following true or false?
a.
b.
c.
d.
e.
f.
g.
If a bond’s yield is exactly equal to its coupon, the price of the bond
must be 100.
The cheapest to deliver bond for a futures contract is the bond with the
lowest implied repo rate.
The longer a bond’s duration, the lower its volatility.
The present value of a future cashflow cannot be greater than the
cashflow itself.
A 1-year deposit is better for the depositor if the rate is 8.60% paid
annually than if it is 8.45% paid semi-annually.
If a bond is trading at a price of 99, the market yield is lower than the
bond’s coupon.
The intrinsic value of the DEM call option in question (5) is 0.05 DEM
per GBP 1.
PART 2
2 HOURS
80 POINTS AVAILABLE
ALL FOUR EXERCISES SHOULD BE ANSWERED.
EXERCISE NO. 1
25 POINTS AVAILABLE
INTERMEDIATE CALCULATIONS MUST BE SHOWN
You have the following bond:
Settlement date:
Previous coupon date:
260
15 June 1998
18 September 1997
10 · A Complete Practice ACI Exam
Coupon:
Maturity date:
Accrued interest calculation basis:
Price / yield calculation basis:
8.0% annually
18 September 2003
ACT/ACT
30/360
a.
Calculate the bond’s yield for settlement on 15 June 1998 if the clean price is
107.50. Show the formula for the bond’s price before calculating the yield.
b.
If you purchase the bond on 15 June 1998 at a price of 107.50, and sell it on
21 August 1998 at 106.40, what is the simple rate of return on your investment
over that period on an ACT/360 basis? What is the effective rate of return on
an ACT/365 basis?
c.
If the above bond is the CTD for the bond futures contract and the cash bond
settlement date is 15 May 1998, what is the theoretical futures price based on
the following?
Delivery date of futures contract:
Short-term money market interest rate:
Clean price of CTD bond:
Previous coupon payment:
Conversion factor:
d.
19 June 1998
5% (ACT/360)
108.00
18 September 1997
1.1000
The actual futures price is quoted in the market at 97.73. Discuss what arbitrage opportunity this may create.
EXERCISE NO. 2
15 POINTS AVAILABLE
INTERMEDIATE CALCULATIONS MUST BE SHOWN
a. What are duration and modified duration? How are they related?
b. You own a portfolio consisting of the following two bonds:
•
•
zero coupon 3-year bond, price 71.18, nominal amount 30 million
20% coupon 4-year bond, price 114.27, nominal amount 10 million
Which has the shorter duration?
c.
What are the modified durations of the two bonds?
d.
If all market yields rise by 10 basis points, what is your approximate profit or loss?
e.
You wish to hedge your portfolio in the short term, against instantaneous
movements in the yield curve, by selling bond futures contracts. What information do you need to calculate how many futures contracts to sell?
EXERCISE NO. 3
20 POINTS AVAILABLE
INTERMEDIATE CALCULATIONS MUST BE SHOWN
Maturity
2 years
3 years
Coupon
8% (annual)
5.5% (annual)
Price
104.50
98.70
261
Part 5 · Practice ACI Exam, Hints and Answers
Based on the above and a 1-year yield of 5.00% (bond basis), calculate the following:
a. The 2-year and 3-year zero-coupon yields and discount factors.
b. The 1-year v 2-year and 2-year v 3-year forward-forward rates.
c. The theoretical yield to maturity of a 3-year 12% annual coupon bond.
d. The 2-year and 3-year par yields.
EXERCISE NO. 4
20 POINTS AVAILABLE
INTERMEDIATE CALCULATIONS MUST BE SHOWN
a.
You have the following interest rate swap on your book:
Notional amount: 50 million
You pay 6-month LIBOR (ACT/360 basis)
You receive a fixed rate of 10.00% (annual payments, 30/360 basis)
The swap started on 2 June 1997 and ends on 2 June 2000
The last interest rate fixing, for 2 December 1998, was 8.5% for 6-month
LIBOR. The spot value date now is 15 April 1999. What is the mark-tomarket value of the swap for value on that date, based on the following
discount factors?
Spot to 2 June 1999:
Spot to 2 December 1999:
Spot to 2 June 2000:
b.
You buy a 3-year 9% annual coupon bond at a price of 103.50, which you
wish to swap to a floating-rate asset with a par initial investment amount and
a regular LIBOR-related income based on this par amount. The current 3year par swap rate is 7.5%. Based on the following discount factors, what
LIBOR-related floating rate should you be able to achieve on this asset
swap? LIBOR is on an ACT/360 basis.
6 months:
1 year:
1 years:
2 years:
2 years:
3 years:
262
0.9885
0.9459
0.9064
0.9650
0.9300
0.8970
0.8650
0.8350
0.8050
11
Hints and Answers
to Exercises and
Practice Exam
Hints on exercises
Answers to exercises
Answers to practice exam
263
Mastering Financial Calculations
HINTS ON EXERCISES
(
1. Future value = present value × 1 + yield ×
2. Present value =
3. Yield =
future value
1 + yield × days
year
(
)
days
year
)
future value
year
– 1) ×
( present
value
days
4. Future value = present value × (1 + yield)N
5. Is a present value generally greater or smaller than a future value?
6. Future value = present value × (1 + yield)N
Interest = future value – principal
7. Present value =
future value
(1 + yield)N
8. Future value = present value × (1 + yield)N
(
future value
9. Yield =
present value
)
1
N
–1
10. Future value =
(
present value × 1 +
first yield
frequency
)
number of periods
(
11. Future value = present value × 1 +
(
× 1+
yield
frequency
)
)
second yield
frequency
number of periods
number of periods
With reinvestment at a different rate, consider each cashflow separately,
reinvested to maturity.
12. Either use the TVM keys on the HP, or calculate the present value of
each cashflow and add them together:
present value =
future value
(1 + yield)N
13. Consider the problem in terms of monthly periods rather than years. On
this basis, how many periods are there and what is the interest rate for
each period? Then use the TVM keys on the HP.
264
11 · Hints and Answers to Exercises and Practice Exam
(
14. Effective rate = 1 +
semi-annual rate 2
–1
2
)
[
]
1
15. Rate = (1 + annual rate) frequency – 1 × frequency
days
16. Future value = present value × er× year
effective rate = er – 1
continuously compounded rate = LN(1 + i)
(
days
17. Effective rate = 1+ i ×
year
)
365
days
[(
daily equivalent rate = 1+ i ×
discount factor =
)
]
1
days days
– 1 × year
year
1
1 + i × days
year
(
)
18. First known rate +
difference between known rates ×
days from first date to interpolated date
days between known dates
19. What is the period between cashflows? What is the interest rate for this
period? Are there any zero cashflows?
The NPV can be calculated either by using the HP cashflow function, or
from first principles:
present value =
future value
(1 + yield)N
20. Use the IRR function on the HP and then consider for what period the
result is expressed.
(
21. Proceeds = face value × 1 + coupon rate ×
22. Price = present value =
future value
1 + yield × days
year
(
)
days
year
)
future cashflow
year
– 1) ×
( present
cashflow
days held
future cashflow
effective yield = (
–1
present cashflow )
simple yield =
365
days
265
Mastering Financial Calculations
23. Overall return =
[
purchase
(1 + yield on purchase × days onyear
) –1
days on sale
(1 + yield on sale × year )
]
×
year
days held
Therefore: yield on sale =
[
(1 + yield on purchase × days onyearpurchase)
(1 + overall return × daysyearheld )
]
–1 ×
year
days on sale
365
24. Rate on ACT/365 basis = rate on ACT/360 basis × 360
(
effective yield (ACT/365 basis) = 1 + interest rate × days
year
360
effective yield on ACT/360 basis = effective yield × 365
25. What is the day/year count?
future value
price = present value =
26. Discount rate =
(1 + yield × days
year)
rate of true yield
(1 + yield × days
year)
discount amount = principal × discount rate ×
27. Rate of true yield =
discount rate
1 – discount rate × days
year
(
days
year
)
(
amount paid = principal × 1 – discount rate ×
days
year
)
28. Discount amount = face value – amount paid
discount rate = discount amount × year
face value
days
29. What is the day/year count?
(
a. Amount paid = principal × 1 – discount rate ×
b. Rate of true yield =
discount rate
1 – discount rate × days
year
(
Then convert to 365-day basis
30. Yield =
266
future cashflow
year
–1)×
( present
cashflow
days held
)
days
year
)
365
) days – 1
11 · Hints and Answers to Exercises and Practice Exam
31. Yield =
future cashflow
year
–1)×
( present
cashflow
days held
32. What is the day/year count in each case?
Is the quote a yield or a discount rate in each case?
33. Convert all rates to the same basis in order to compare them – for example, true yield, on a 365-day basis.
34. Taking account of non-working days as appropriate, what was the last
coupon date, and what are the remaining coupon dates?
How many days are there between these dates and what are the exact
coupon payments?
Discount each cashflow back to the previous date, using exact day
counts, add the actual cashflows for that date, and so on back to the
settlement date.
35. Forward-forward rate =
(
(
[
1 + longer rate ×
1 + shorter rate ×
days
year
)
)
days
year
]
–1 ×
(
year
days difference
)
If the above is based on middle rates rather than offered rates, you
should add around 0.06% to benchmark against LIBOR.
36. a. For the FRA, are you a borrower (protecting against the risk of
higher rates) or an investor (protecting against the risk of lower rates)?
b. The price-taker always gets the worse price.
c. Consider the cashflows – exactly what amount will you be rolling over?
d. FRA settlement amount = principal ×
(FRA rate – LIBOR) × days
year
(1 + LIBOR × days
year)
e. Consider all the exact cashflows and timings and on which side of
the market you will be dealing.
37. Remember that the profit / loss relates to a 3-month period rather than a
whole year.
38. Create a strip.
39. Calculate the implied 3 v 9 and 6 v 12 rates.
Interpolate for 3 v 7 and 6 v 10.
Interpolate further for 4 v 8.
The hedge follows the same construction.
267
Mastering Financial Calculations
40. First, calculate the various cash forward-forward rates (3 v 6, 6 v 9, 3 v 9)
Then, compare the various combinations possible:
• forward-forward, FRA or futures for 3 v 6
• forward-forward, FRA or futures for 6 v 9
• forward-forward or FRA for 3 v 9
41. Use the TVM function of the HP.
42. What are all the cashflows from the bond?
Clean price = NPV using the yield.
Clean price = dirty price because there is no accrued coupon.
Current yield =
coupon rate
clean price
100
coupon rate +
Simple yield to maturity =
Duration =
amount – clean price
(redemption
)
years to maturity
clean price
100
∑ (present value of cashflow × time to cashflow)
dirty price
43. This question is complicated by the fact that the calculation bases for
accrued coupon and price are different.
• Calculate the clean price and the accrued interest assuming that both
are calculated on an ACT/ACT basis.
• Add together to give the correct dirty price.
• Recalculate the accrued interest on the correct 30/360 basis.
• Subtract this from the dirty price to give the correct clean price.
Or, using the bond price formula rather than the functions built into the
HP calculator:
Dirty price =
100
(1 + ni )w
[
(
(
1–
R
n ×
1
1 + ni
(
1–
)
))
)N
1
1 + ni
(
1
+
]
(1 + ni )N–1
Clean price = dirty price – accrued coupon.
44. If you use the HP calculator’s built-in bond functions, it is again necessary
to make an adjustment for the fact that the price / yield calculation is on a
30/360 basis but the accrued coupon is on an ACT/365 basis, as follows:
•
•
•
•
268
Calculate the correct accrued interest.
Add to the clean price to give the correct dirty price.
Calculate the accrued coupon as if it were on a 30/360 basis.
Subtract from the dirty price to give an adjusted clean price.
11 · Hints and Answers to Exercises and Practice Exam
45. What is the fraction of a period to the next quasi-coupon date?
Price =
100
(1 + yield
)
2
(number of periods to maturity)
46. True yield on bond year basis =
– days
+
365
47. yield =
(
discount rate
× 365
days
(1 – discount rate × 360 360
2
× 2 × (days
–1 ×
(days
365 )
365 2)
)
((
1
1–D×
days
360
)
)
∑-q
–1
–1
(days
365 2)
48. This needs the same equation as the previous question. However, you need
to manipulate the equation into the form “D = ...” rather than “i = ...” .
49. The HP calculator bond function cannot be used for a bond with stepped
coupons. The easiest method is to work from first principles, as follows:
•
•
•
•
•
Discount the final cashflow to a value one year earlier.
Add the coupon cashflow paid then and discount back a further year.
Repeat the process back to the first remaining coupon.
Discount back to settlement date (what is the day year basis?) to give the
current dirty price.
Subtract the accrued interest to give the clean price.
50. Because bond price / yield formulas generally assume a redemption
amount of 100, one approach is to scale down every cashflow by the
same factor to correspond to a redemption amount of 100.
sale proceeds
year
–1)×
( amount
invested
days
sale proceeds
Effective return = (
–1
amount invested)
Simple return =
365
days
51. For each one:
• Are coupons paid annually or semi-annually?
• What was the last coupon date?
• What is the day/year basis?
52. Compare the cost of funding with the current yield. The difference
between the futures price and the bond price should compensate for this.
53. Either build up the price from the arbitrage mechanism:
• Buy the bond.
• Borrow to finance the bond purchase.
269
Mastering Financial Calculations
• At delivery of the futures contract, repay the financing plus interest.
• Deliver the bond in return for payment plus accrued.
Or
Theoretical futures price =
–
([bond price + accrued coupon now] × [1 + i × days
year ])
(accrued coupon at delivery of futures)
conversion factor
54.
(futures price × conversion factor) +
(accrued coupon at delivery of futures)
year
Implied repo rate =
–1 ×
days
(bond price + accrued coupon now)
[
]
55. Assume the cash-and-carry arbitrage is:
•
•
•
•
Buy the cash CTD bond now.
Fund this purchase by repoing the bond.
Sell the bond futures contract.
Deliver the bond at maturity of the futures contract.
Accrued coupon for CTD bond = ?
Cost of buying CTD bond per DEM 100 nominal = ?
Total borrowing (principal + interest) to be repaid at the end = ?
Anticipated receipt from selling futures contract and delivering bond per
DEM 100 nominal = ?
Profit per DEM 100 nominal = ?
Size of DEM bond futures contract = ?
Face value of bond purchased in the arbitrage = ?
Therefore profit per futures contract = ?
56. For each bond, calculate the yield, the modified duration, the accrued
interest, the dirty price, then the total value.
∑ (modified duration × value)
modified duration of portfolio ~
~
portfolio value
change in value ~ – value × change in yield × modified duration
57. For each bond, calculate the yield, the modified duration, the accrued
interest and the dirty price.
270
11 · Hints and Answers to Exercises and Practice Exam
Hedge ratio =
notional amount of futures contract required to hedge a position in bond A
=
face value of bond A
dirty price of bond A × modified duration of bond A
dirty price of CTD bond
modified duration of CTD bond
×
conversion factor for CTD bond
1 + i × days
year
(
)
where i = short-term funding rate
58. Bootstrap to create the zero-coupon yields and discount factors.
1 year v 2 year forward-forward =
1-year discount factor
– 1 etc.
2-year discount factor
59. a. Create the zero-coupon yields from strips of the 1-year rate and
forward-forwards.
Calculate the discount factors.
The par yield is the coupon of a bond such that the NPV of the bond’s
cashflows (using the discount factors) is par.
b. Calculate the NPV of the cashflows using the discount factors.
Use the TVM function of the HP to calculate the yield.
60. Bootstrap to create the 18-month and 24-month discount factors
forward-forward rate =
18-month discount factor
year
– 1] ×
[ 24-month
discount factor
days
61. What are the day/year bases?
– base currency rate × days
(variable currency rate × days
year
year)
forward swap = spot ×
days
(1 + base currency rate × year)
62. a. Indirect rates: divide opposite sides. Customer gets the worse price.
b. One direct rate and one indirect: multiply same sides.
c. Add or subtract the forward points?
d. Add or subtract the forward points?
e. Is sterling worth more forward than spot or vice versa?
f. Similar to (d) and (e).
g. Forward points = outright – spot.
271
Mastering Financial Calculations
63. a. The value date is after spot (add or subtract forward points?).
b. The value date is before spot (add or subtract forward points?).
c. The customer gets the worse price.
d. Similar to (c).
e. Take the difference between opposite sides.
f. Should the price be bigger or smaller than the one-month swap? Take
care with +/– signs.
64. a. Calculate NOK and FRF outrights against the USD.
Calculate cross-rate spots and outrights.
Cross-rate swap = outright – spot.
Forward-forward price is difference between opposite sides.
b. For a swap from before spot to after spot, add the same sides.
65. a. You need to interpolate between the 1-month and the 2-month dates.
Then the method is similar to 64(a).
b. Similar to 64(b) but combine the O/N price as well as the T/N.
c. Again, combine the O/N and T/N.
66. a. The big figure on the offer side of USD/ITL spot is 1634. The 6-month
USD/ITL forward swap price means 22.37 lire / 22.87 lire.
b. Assume that the expected changes happen, and calculate the effect on
the forward outright price, using middle prices for the comparison.
67. Either consider the exact cashflows:
• Initial DEM investment = ?
• Total proceeds at maturity of CP = ?
• Buy and sell USD (sell and buy DEM) spot against 3 months
Or use the formula for covered interest arbitrage:
variable currency rate =
variable year
– 1] ×
[(1 + base currency rate × basedaysyear) × outright
spot
days
68. Action now
(i) Arrange FRA on a notional 3 v 9 borrowing of USD.
(ii) Convert this notional loan from USD to SEK via a foreign exchange
swap.
Action in 3 months’ time
(iii) Assume a borrowing of SEK.
(iv) Convert this borrowing to a USD borrowing to match (i), via a foreign exchange swap.
Settlement at the end of 9 months
(i) Receive deferred FRA settlement.
272
11 · Hints and Answers to Exercises and Practice Exam
69. Write out all the resulting cashflows, then calculate present values.
70. a. Value the DEM cashflows in USD using current outrights. Recalculate
the outrights after the spot rate movement, then revalue the DEM
cashflows.
b. Calculate the NPV of these net future cashflows using an appropriate
USD interest rate for each period.
Calculate the NPV of the original DEM positions using an appropriate
DEM interest rate for each period; the appropriate spot hedge should
offset this NPV.
71. On what basis is the swap quoted? Convert the absolute swap rate and
the bond coupon both to semi-annual money market. The difference represents the approximate sub-LIBOR spread.
72. a. Convert the futures prices to implied interest rates. Then for each
maturity, create a zero-coupon rate from a strip of 3-month rates. Is
this on a bond basis or a money market basis? Calculate the effective
annual equivalent.
b. Calculate the par rate in the same way that you would calculate a par
bond yield – the coupon and yield are the same for an instrument
priced at par. The quarterly coupon cashflows need to be calculated on
a quarterly money market basis.
73. a The USD swap cashflows match the remaining bond cashflows
(including the principal). What is the NPV in USD of these cashflows?
Convert to GBP at spot. The GBP side of the swap must have an NPV
equal to this. The GBP swap cashflows can therefore be 11% per
annum plus principal, based on this NPV amount.
b. Long-dated forward outright = spot ×
(1 + variable interest rate)N
(1 + base interest rate)N
Convert the USD bond cashflows to GBP at the forward rates.
c. What is the NPV of the alternative GBP cashflow streams, using various rates of discount to calculate the NPV?
74. Convert the USD cash raised from the bond issue to CHF and create
CHF swap cashflows (floating-rate interest payments plus principal) on
this amount. Calculate the NPV of the USD swap cashflows (which
match all the bond cashflows) and convert to CHF at spot; the NPV of
the CHF swap cashflows needs to equal this amount.
Therefore adjust the CHF interest payments by a regular amount which
brings the NPV of all the CHF cashflows to this amount.
75. Write out the cashflows in each currency, remembering to include the
final principal payments. Calculate the NPV of the USD cashflows using
the USD discount factors.
273
Mastering Financial Calculations
Some of the DEM cashflows are unknown because they depend on future
LIBOR fixings. Eliminate these by adding an appropriate FRN structure
beginning on 25 May 1998. Alternatively, calculate forward-forward
rates for the future LIBOR fixings. Then calculate the NPV of the net
DEM cashflows using the DEM discount factors. Convert this NPV to
USD and net against the USD NPV already calculated.
76. Write out all the cashflows arising from issuing USD100 face value of the
bond. Add the cashflows arising from a swap based on a notional
amount of USD100. Consider the net result as a structure of 100 borrowed, 100 repaid at maturity and (100 × LIBOR × q-∑ × eyt
–
´¥π) each six
months plus some irregular cashflows.
Calculate the NPV of these irregular cashflows.
Offset them by matching cashflows and replace by a series of regular sixmonthly cashflows with the same NPV.
What spread above or below LIBOR is necessary to generate these regular six-monthly cashflows?
day 2 price
77. From the ten price data, calculate nine daily relative price changes ( day 1 price
etc.).
Take the natural logarithm of each relative price change.
Calculate the standard deviation of these nine logarithms, as usual:
•
•
•
•
•
Calculate the mean.
Calculate the differences from the mean.
Square the differences.
Add the squares and divide by eight (one less than the number of data)
to give the variance.
The standard deviation is the square root of the variance.
The annualized volatility is:
standard deviation ×
number of data observations per year
78. Convert the FRF call option premium to a cost in FRF.
Use the put / call relationship expressed in units of the variable currency:
premium for call on base currency – premium for put on base currency
= present value of (forward – strike)
Convert the result back to percentage of the USD amount.
79. Calculate the probability (p) of an up movement in the price and of a
down movement (1 - p):
The expected outcome after 1 month is [p × increased price + (1 – p) ×
decreased price]. This should equal the result of depositing 100 for 1
month at the risk-free interest rate.
274
11 · Hints and Answers to Exercises and Practice Exam
Construct a tree showing all the possible outcomes at the end of
three months.
Calculate the probability of arriving at each of these outcomes by combining the probabilities along each route along the tree.
Which of these outcomes would make the option in-the-money at expiry?
What would the profit be for each outcome?
Multiply each profit by the probability of it happening, and add to give
the expected value of the option.
The PV of this expected value is the option’s premium.
275
Mastering Financial Calculations
ANSWERS TO EXERCISES
(
1. Future value = £43 × 1 + 0.075 ×
)
120
= £44.06
365
.075 ENTER 120 × 365 ÷ 1 + 43 ×
2. Present value =
£89
1 + 0.101 ×
(
93
365
)
= £86.77
.101 ENTER 93 × 365 ÷ 1 + 89 ■ xy ÷
3. Yield =
365
– 1) ×
= 10.05%
( 83.64
83.00
28
83.64 ENTER 83 ÷ 1 – 365 × 28 ÷
4. £36 × (1 + 0.09)10 = £85.23
1.09 ENTER 10 ■ ∧ 36 ×
5. Choose DEM1,000 now unless interest rates are negative. With positive rates, DEM1,000 now must be worth more than a smaller
amount in the future.
6. £342 × (1 + 0.06)5 = £457.67
£457.67 – £342 = £115.67
1.06 ENTER 5 ■ ∧ 342 × 342 –
7. DEM
98
= DEM 58.16
(1 + 0.11)5
1.11 ENTER 5 ■ ∧ 98 ■ xy ÷
8. £1,000 × (1 + 0.054)4 = £1,234.13
276
11 · Hints and Answers to Exercises and Practice Exam
1.054 ENTER 4 ■ ∧ 1,000 ×
OR
FIN TVM
4N
1,000 +/- PV
0 PMT
5.4 I% YR
FV
9.
(
)
1
1,360.86 7
– 1 = 4.50%
1,000
1,360.86 ENTER 1,000 ÷
7 ■ 1/x ■ ∧ 1 –
OR
FIN TVM
7N
1,000 +/- PV
0 PMT
1360.86 FV
I%YR
(
10. £1,000,000 × 1 +
0.06 20
0.065 10
× 1+
= £1,854,476.99
4
2
) (
)
.06 ENTER 4 ÷ 1 + 20 ■ ∧
.065 ENTER 2 ÷ 1 + 10 ■ ∧ ×
1,000,000 ×
(
11. £1,000,000 × 1 +
0.085 4
= £1,087,747.96
4
)
.085 ENTER 4 ÷ 1 + 4 ■ ∧ 1,000,000 x
With reinvestment at 8.0%:
0.085
0.08 3
× 1+
4
4
( )
0.085
0.08
Second interest payment plus reinvestment: £1,000,000 ×
× (1 +
4
4 )
0.085
0.08
Third interest payment plus reinvestment: £1,000,000 ×
× (1 +
4
4 )
First interest payment plus reinvestment:
£1,000,000 ×
2
Fourth interest payment plus reinvestment: £1,000,000 ×
Principal amount:
Total:
0.085
4
£1,000,000
£1,087,584.17
277
Mastering Financial Calculations
.08 ENTER 4 ÷ 1 + 3 ■ ∧
.08 ENTER 4 ÷ 1 + 2 ■ ∧ +
.08 ENTER 4 ÷ 1 + +
1,000,000 × .085 × 4 ÷
.085 ENTER 4 ÷ 1 + 1,000,000 × +
12. £32,088.29
FIN TVM
10 N
9 I%YR
5,000 PMT
0 FV
PV
13. There are 300 payment periods. The interest for each period is
The regular payment must be £650.53.
FIN TVM
300 N
7.25 ENTER 12 ÷ I%YR
90,000 PV
0 FV
PMT
(
14. 1 +
0.114 2
– 1 = 11.72%
2
)
.114 ENTER 2 ÷ 1 + 2 ■ ∧ 1 –
15. [(1 + 0.12)q-® – 1] × 4 = 11.49%
[(1 + 0.12) œ_q∑ – 1] × 12 = 11.39%
1.12 ENTER 4 ■ 1/x ■ ∧ 1 – 4 x
1.12 ENTER 12 ■ 1/x ■ ∧ 1 – 12 x
16. £1,000,000 × e0.07 = £1,072,508.18
Effective rate is 7.2508% per annum
■ MATH LOGS .07 EXP 1,000,000 ×
278
7.25%
12
.
11 · Hints and Answers to Exercises and Practice Exam
LN(1.09) = 8.6178% is the continuously compounded rate.
■ MATH LOGS 1.09 LN
365
(
17. Effective rate = 1 + 0.065 ×
Daily equivalent rate =
Discount factor =
)
138 138
– 1 = 6.6321%
365
[(
138
1 + 0.065 ×
365
1
138
) – 1] × 365 = 6.4220%
1
= 0.9760
138
1 + 0.065 × 365
(
)
.065 ENTER 138 × 365 ÷ 1 + 365 ENTER 138 ÷ ■ ∧ 1 –
.065 ENTER 138 × 365 ÷ 1 + 138 ■ 1/x ■ ∧ 1 – 365 ×
.065 ENTER 138 × 365 ÷ 1 + ■ 1/x ■
18. 5.2% + (5.4% – 5.2%) ×
(41 – 30)
= 5.2733%
(60 – 30)
41 ENTER 30 – 60 ENTER 30 – ÷
5.4 ENTER 5.2 – ×
5.2 +
19. Because the cashflows are 6-monthly, the effective annual interest rate
must be converted to an equivalent rate for this 6-monthly period, rather
than an annual rate:
1
(1.10)2 – 1 = 4.88%
The NPV can then be calculated either by using the HP cashflow function (remembering that the 30-month cashflow is zero), or from first
principles as:
–$105 –
$47
$47
$47
$93
$450
–
–
–
+
= $27.95
(1.0488)6
(1.0488) (1.0488)2 (1.0488)3 (1.0488)4
*
FIN CFLO GET NEW
[If necessary to clear previous data, type “CLEAR DATA” followed by “YES”]
105 +/- INPUT
47 +/- INPUT 3 INPUT
93 +/- INPUT INPUT
0 INPUT INPUT
450 INPUT INPUT
279
Mastering Financial Calculations
CALC
1.1 ENTER ■
NPV
x 1 – 100 × I%
OR
1.1 ENTER ■ x STO 1
6 ■ ∧ 450 ■ xy ÷
93 RCL 1 4 ■ ∧ ÷ –
47 RCL 1 3 ■ ∧ ÷ –
47 RCL 1 2 ■ ∧ ÷ –
47 RCL 1 ÷ –
105 –
20. 7.047% is the IRR on the basis of the semi-annual periods. This is then
annualized:
(1 + 0.07047) 2
– 1 = 14.59%
Following on from the previous calculation using the HP cashflow function:
IRR%
100 ÷ 1 + 2 ■ ∧ 1 –
(
21. £1,000,000 × 1 + 0.11 ×
)
181
= £1,054,547.95
365
.11 ENTER 181 x 365 ÷ 1 + 1,000,000 x
22.
(
181
£1,000,000 × 1 + 0.11 × 365
(1 + 0.10 × )
134
365
) = £1,017,204.02 price
.11 ENTER 181 × 365 ÷ 1 + 1,000,000 x
.1 ENTER 134 × 365 ÷ 1 + ÷
[
134
(1 + 0.10 × 365
) –1
71
(1 + 0.095 × 365)
]
×
365
= 10.37% simple return
63
.1 ENTER 134 × 365 ÷ 1 +
.095 ENTER 71 × 365 ÷ 1 + ÷
1 - 365 × 63 ÷
[
280
134
(1 + 0.10 × 365
)
71
(1 + 0.095 × 365)
365
63
]
– 1 = 10.83% effective return
11 · Hints and Answers to Exercises and Practice Exam
.1 ENTER 134 × 365 ÷ 1 +
.095 ENTER 71 × 365 ÷ 1 + ÷
365 ENTER 63 ÷ ■ ∧ 1 –
23.
134
(1 + 0.10 × 365
)–1
71
(1 + i × 365)
[
]
Therefore i =
[
× 365
= 10.00%
63
134
(1 + 0.10 × 365
)–1
63
(1 + 0.10 × 365)
]
× 365
= 9.83%
71
.1 ENTER 134 × 365 ÷ 1 +
.1 ENTER 63 × 365 ÷ 1 + ÷
1 – 365 × 71 ÷
24. 11.5% ×
365
360
= 11.66%
(
365
91
)
91
1 + 0.115 ×
360
12.18% ×
– 1 = 12.18%
360
= 12.01%
365
11.5 ENTER 365 × 360 ÷
.115 ENTER 91 × 360 ÷ 1 + 365 ENTER 91 ÷ ■ ∧ 1 –
360 × 365 ÷
yw
25. Day/year count is ACT/365 basis – that is, ´–
¥† in this case.
Purchase price =
£2,000,000
62
(1 + 0.082 × 365
)
= £1,972,525.16
.082 ENTER 62 × 365 ÷ 1 + 2,000,000 ■ xy ÷
26.
9.5%
1 + 0.095 ×
(
60
365
)
= 9.35%
9.35% × £1,000,000 × 60 = £15,369,86
365
.095 ENTER 60 × 365 ÷ 1 + .095 ■ xy ÷
.0935 ENTER 1,000,000 × 60 × 365 ÷
281
Mastering Financial Calculations
27.
9.5%
1 – 0.095 ×
(
60
365
)
= 9.65%
9.5% × £1,000,000 × 60 = £15,616.44
365
Amount paid = £ 1,000,000 – £15,616.44 = £984,383.56
.095 ENTER 60 × 365 ÷ 1 – +/- .095 ■ xy ÷
.095 ENTER 60 × 365 ÷ 1 – +/- 1,000,000 ×
28.
– 975,000
= 15.21%
(1,000,000
) × 365
1,000,000
60
1,000,000 ENTER 975,000 – 1,000,000 ÷ 365 x 60 ÷
(
29. a. Amount paid = $1,000,000 × 1 – 0.065 ×
b. Yield =
)
91
= $983,569.44
360
6.5%
× 365 = 6.70%
91
1 – 0.065 × 360 360
(
)
.065 ENTER 91 × 360 ÷ 1 – +/- 1,000,000 ×
.065 ENTER 91 × 360 ÷ 1 – +/- 6.5 ■ xy ÷ 365 × 360 ÷
30.
112
(1 – 0.067 × 360
)–1
176
(1 – 0.070 × 360)
[
]
× 365
= 7.90%
64
.067 ENTER 112 × 360 ÷ 1 –
.07 ENTER 176 × 360 ÷ 1 – ÷
1 – 365 × 64 ÷
(
)–1
176
(1 – 0.070 × 360)
31. 1 – 0.075 × 172
360
[
]
× 365
= –15.22%
4
.075 ENTER 172 × 360 ÷ 1 –
.07 ENTER 176 × 360 ÷ 1 – ÷
1 – 365 × 4 ÷
32. US
(
US$1,000,000 × 1 – 0.05 ×
282
)
91
= US$987,361.11
360
11 · Hints and Answers to Exercises and Practice Exam
UK
(
£1,000,000 × 1 – 0.05 ×
)
91
= £987,534.25
365
Belgium
BEF1,000,000 = BEF987,687.73
91
1 + 0.05 × 365
(
)
France
FRF1,000,000 = FRF987,518.86
91
1 + 0.05 × 360
(
)
.05 ENTER 91 × 360 ÷ 1 – +/- 1,000,000 ×
.05 ENTER 91 × 365 ÷ 1 – +/- 1,000,000 ×
.05 ENTER 91 × 365 ÷ 1 + 1,000,000 ■ xy ÷
.05 ENTER 91 × 360 ÷ 1 + 1,000,000 ■ xy ÷
33. Convert all rates, for example to true yield on a 365-day basis to compare:
30-day T-bill (£) 8q-®% discount rate
yield =
8.25%
30
[1 – 0.0825 × 365
]
= 8.3063%
.0825 ENTER 30 × 365 ÷ 1 – +/- 8.25 ■ xy ÷
30-day UK CP (£) 8.1875% yield
30-day ECP (£) 8.125% yield
30-day US T-bill 8.3125% discount rate
yield =
8.3125%
30
[1 – 0.083125 × 360
]
= 8.3705% ×
= 8.3705% on 360-day basis
365
= 8.4867% on 365-day basis
360
.083125 ENTER 30 × 360 ÷ 1 – +/- 8.3125 ■ xy ÷ 365 × 360 ÷
30-day interbank deposit (£) 8.25% yield
30-day US CP 8.5% discount rate on 360-day basis
yield =
8.5%
30
[1 – 0.085 × 360
]
= 8.5606% on 360-day basis
283
Mastering Financial Calculations
365
= 8.6795% on 365-day basis
360
= 8.5606% ×
.085 ENTER 30 × 360 ÷ 1 – +/- 8.5 ■ xy ÷ 365 × 360 ÷
30-day US$ CD 8.625% yield on ACT/360 basis
= 8.625% ×
365
= 8.7448% on 365-day basis
360
30-day French T-bill 8.5% yield on ACT/360 basis
= 8.5% ×
365
= 8.6181% on 365-day basis
360
Therefore in descending order:
US$ CD
US CP
French T-bill
US T-bill
UK T-bill (£)
Interbank deposit (£)
UK CP
ECP (£)
8.7448%
8.6795%
8.6181%
8.4867%
8.3063%
8.25%
8.1875%
8.125%
34. The last coupon date was:
(0) 26 March 1999
The remaining coupon dates are: (1) 27 September 1999 (26 September
is a Sunday)
(2) 27 March 2000 (26 March is a
Sunday)
(3) 26 September 2000
(4) 26 March 2001
with the same notation as before,
F
R
year
dp1
d01
d12
d23
d34
i
=
=
=
=
=
=
=
=
=
(
A1 = 1 + 0.08 ×
1,000,000
0.075
360
130
185
182
183
181
0.08
)
130
= 1.028889
360
182
= 1.070502
(
360)
183
A = 1.070502 × (1 + 0.08 ×
= 1.114035
360)
A2 = 1.028889 × 1 + 0.08 ×
3
284
11 · Hints and Answers to Exercises and Practice Exam
(
)
181
= 1.1158844
360
R × d01 + d12 + d23 + d34 + 1
P = F × year
A1
A2
A3
A4
A4
A4 = 1.114035 × 1 + 0.08 ×
[
) ]
(
= $1,000,000
0.075
185
182
183
181
1
×
×
+
+
+
+
360
1.028889 1.070502 1.114035 1.158844 1.158844
[
(
)
]
= $1,002,569.65
.08 ENTER 130 × 360 ÷ 1 + STO1
.08 ENTER 182 × 360 ÷ 1 + × STO2
.08 ENTER 183 × 360 ÷ 1 + × STO3
.08 ENTER 181 × 360 ÷ 1 + × STO4
185 ENTER RCL1 ÷
182 ENTER RCL2 ÷ +
183 ENTER RCL3 ÷ +
181 ENTER RCL4 ÷ +
.075 × 360 ÷
RCL4 ■ 1/x ÷ +
1,000,000 ×
35. Using middle-market rates:
(
273
1 + 0.1006 × 360
1 + 0.09935 ×
91
360
)
–1 ×
360
= 9.87%
(273 – 91)
As we have used middle rates, we need to add approximately 0.06% to
give a rate which can be settled against LIBOR:
9.87% + 0.06% = 9.93% middle FRA
.1006 ENTER 273 × 360 ÷ 1 +
.09935 ENTER 91 × 360 ÷ 1 + ÷
1 – 360 × 273 ENTER 91 – ÷
An only slightly different result can be calculated by using the offer side
of the 3-month and 6-month rates instead of middle rates, and then not
adding 0.06%.
36. a. Sell the FRA to cover the deposit which will need to be rolled over
b. 3 v 6 FRA at 7.10%
c. Ideally, cover the maturing amount of the 3-month deposit:
(
DEM 5 million × 1 + 0.0675 ×
)
91
= DEM 5,085,312.50
360
d. DEM 5,085,312.50 × (7.10% – 6.90%) ×
92
360
92
(1 + 0.069 × 360
)
= DEM 2,554.12 received by you (the FRA seller)
285
Mastering Financial Calculations
.071 ENTER .069 – 92 × 360 ÷ 5,085,312.50 ×
.069 ENTER 92 × 360 ÷ 1 + ÷
e. Roll over the maturing deposit plus FRA settlement amount at LIBID
to give:
(
DEM (5,085,312.50 + 2,554.12) × 1 + 0.0685 ×
92
360
)
= DEM 5,176,932.55
(
Total borrowing repayment = DEM 5 million × 1 + 0.07 ×
)
183
360
= DEM 5,177,916.67
Net loss = DEM 984.12
2,554.12 ENTER 5,085,312.5 + .0685 ENTER 92 × 360 ÷ 1 + ×
.07 ENTER 183 × 360 ÷ 1 + 5,000,000 × –
37. Selling a futures contract implies expecting interest rates to rise
Profit / loss = size of contract ×
= USD1 million ×
change in price
1
×
100
4
(94.20 – 94.35) 1
× = USD 375 loss
100
4
38. Create a strip from the implied forward interest rates for each 3-month
period:
92
91
90
) × (1 + 0.048 × 360
) × (1 + 0.0495 × 360
) – 1] × 360
[(1 + 0.0455 × 360
273
= 4.82%
.0455 ENTER 92 × 360 ÷ 1 +
.048 ENTER 91 × 360 ÷ 1 + ×
.0495 ENTER 90 × 360 ÷ 1 + ×
1 – 360 × 273 ÷
39. The FRA rates implied by the futures prices are:
3 v 6 (92 days):
6 v 9 (91 days):
9 v 12 (90 days):
4.55%
4.80%
4.95%
[(
The implied 3 v 9 rate is 1 + 0.0455 ×
) (
= 4.7021%
.0455 ENTER 92 × 360 ÷ 1 + .048 ENTER 91 × 360 ÷ 1 + ×
1 – 360 × 183 ÷
286
) ]
92
91
360
× 1 + 0.048 ×
–1 ×
360
360
183
11 · Hints and Answers to Exercises and Practice Exam
[(
The implied 6 v 12 rate is 1 + 0.048 ×
) (
) ]
91
90
360
× 1 + 0.0495 ×
–1 ×
360
360
181
= 4.9044%
.048 ENTER 91 × 360 ÷ 1 + .0495 ENTER 90 × 360 ÷ 1 + ×
1 – 360 × 181 ÷
Interpolation gives:
3 v 7 rate = 3 v 6 rate + (3 v 9 rate – 3 v 6 rate) ×
30
= 4.6001%
91
6 v 10 rate = 6 v 9 rate + (6 v 12 rate – 6 v 9 rate ) ×
31
= 4.8360%
90
Further interpolation gives:
4 v 8 rate = 3 v 7 rate + (6 v 10 rate – 3 v 7 rate) ×
30
= 4.68%
92
For the hedge, use effectively the same construction by interpolation, but
in “round amounts” because futures contracts can be traded only in
standardized sizes:
FRA 4 v 8 is equivalent to
2
1
(FRA 3 v 7) + (FRA 6 v 10)
3
3
( 23 (FRA 3 v 6) + 13 (FRA 3 v 9)) + 13 ( 23 (FRA 6 v 9) + 13 (FRA 6 v 12))
=
2
3
=
4
2
2
1
(FRA 3 v 6) + (FRA 3 v 6 + FRA 6 v 9) + (FA 6 v 9) + (FRA 6 v 9 + FRA 9 v 12)
9
9
9
9
=
6
5
1
(FRA 3 v 6 ) + (FRA 6 v 9) + (FRA 9 v 12)
9
9
9
Therefore for each USD9 million FRA sold to the customer, you sell 6
June futures, 5 September futures and 1 December futures. When the
June futures contracts expire, replace them by 6 September futures. This
will create a basis risk, hedged by selling a further 6 September futures
and buying 6 December futures, giving a net position then of short
17 September futures and long 5 December futures.
40. Forward-forward borrowing costs created from the cash market are as
follows:
3 v 6:
6 v 9:
3 v 9:
[
[
[
183
(1 + 0.0475 × 360
) – 1 × 360 = 4.9549%
92
91
(1 + 0.045 × 360)
273
(1 + 0.049 × 360
) – 1 × 360 = 5.3841%
183
90
(1 + 0.046 × 360)
273
(1 + 0.049 × 360
) – 1 × 360 = 5.0453%
92
181
(1 + 0.045 × 360)
]
]
]
287
Mastering Financial Calculations
.0475 ENTER 183 × 360 ÷ 1 + .045 ENTER 92 × 360 ÷ 1 + ÷
1 – 360 × 91 ÷
.049 ENTER 273 × 360 ÷ 1 + .046 ENTER 183 × 360 ÷ 1 + ÷
1 – 360 × 90 ÷
.049 ENTER 273 × 360 ÷ 1 + .045 ENTER 92 × 360 ÷ 1 + ÷
1 – 360 × 181 ÷
(3 v 6)
(6 v 9)
(3 v 9)
3 v 6 period
Forward-forward: 4.9459%
FRA: 4.96%
September futures (100 - 95.03): 4.97%
}
forward-forward is cheapest
6 v 9 period
Forward-forward: 5.3841%
FRA: 5.00%
December futures (100 - 95.05): 4.95%
}
December futures is cheapest
3 v 9 period
Forward-forward: 5.0453%
FRA: 5.07%
} forward-forward is cheaper
Combining the 3 v 6 forward-forward and December futures gives a cost of:
91
90
360
= 4.98%
) × (1 + 0.0495 × 360
) – 1] × 181
[(1 + 0.049459 × 360
.049459 ENTER 91 × 360 ÷ 1 + .0495 ENTER 90 × 360 ÷ 1 + ×
1 – 360 × 181 ÷
This is cheaper than the 3 v 9 forward-forward. Therefore the cheapest
cover is provided by borrowing for 6 months at 4.75% and depositing
for 3 months at 4.50% to create a 3 v 6 forward-forward, and selling
10 December futures at 95.05. (This ignores any balance sheet costs of
the forward-forward.)
41. Using HP calculator: 7.23%
FIN TVM
15 N
102.45 +/- PV
7.5 PMT
100 FV
I%YR
42. Cashflows remaining are FRF 8 million after 1 year, FRF 8 million after
2 years and FRF 108 million after 3 years. Discount to NPV at 7.0%:
Cost = FRF
8,000,000 8,000,000 108,000,000
+
+
(1 + 0.07) (1 + 0.07)2
(1 +0.07)3
= FRF 102,624,316.04
288
11 · Hints and Answers to Exercises and Practice Exam
8,000,000 ENTER 1.07 ÷
1.07 ENTER 2 ■ ∧ 8,000,000 ■ xy ÷ +
1.07 ENTER 3 ■ ∧ 108,000,000 ■ xy ÷ +
8 = 7.80%
102.62
Current yield =
Simple yield to maturity = 8 +
(100 – 102.62)
3
102.62
= 6.94%
8 ENTER 102.62 ÷
100 ENTER 102.62 – 3 ÷ 8 + 102.62 ÷
Duration =
8
1.07
8
(1.07)2
×1+
×2+
108
(1.07)3
(current yield)
(simple yield to maturity)
×3
102.62
years = 2.79 years
8 ENTER 1.07 ÷
1.07 ENTER 2 ■ ∧ 8 ■ xy ÷ 2 x +
1.07 ENTER 3 ■ ∧ 108 ■ xy ÷ 3 x +
102.62 ÷
43. Clean price =
3.4
(1 +
)
0.074
2
134
181
3.4
+
(1 +
1 + 134
181
)
0.074
2
3.4
+
(1 +
0.074
2
2 + 134
181
)
......+
103.4
(1 +
0.074
2
14 + 134
181
)
(
– 6.8 × 46
360
)
The price is 96.64. The accrued coupon amount is 43,444.44.
This question is complicated by the fact that the calculation bases for
accrued coupon and price are different. To make the calculation using the
HP it is therefore necessary to:
• Calculate the clean price (96.6261) and the accrued interest (0.8829)
•
•
•
using HP, assuming that both are calculated on an ACT/ACT basis.
96.621 + 0.8829 = 97.5090
Add together to give the correct dirty price.
Re-calculate the accrued interest on the correct 30/360 basis.
6.8 × ´–
&ry&
¥π = 0.8689
Subtract this from the dirty price to give the correct clean price.
97.5090–0.8689 = 96.64
FIN BOND
TYPE A/A SEMI EXIT
14.111997 SETT
28.032005 MAT
6.8 CPN%
MORE 7.4 YLD%
PRICE
ACCRU
+
(Clean price assuming ACT/ACT accrued)
(Accrued coupon assuming ACT/ACT)
(Actual dirty price)
289
Mastering Financial Calculations
MORE TYPE 360 EXIT
MORE ACCRU
–
ACCRU 100 ÷ 5,000,000 ×
(Actual accrued coupon)
(Actual clean price)
(Amount of accrued coupon)
Or, using the bond price formula rather than the functions built into the
HP calculator:
Dirty price =
100
134
181
(1 + 0.074
2 )
[
0.068 ×
2
(1 – (
(1 – (
1+
1
0.074
2
)+ 1
(1 +
))
15
)
1
1 + 0.074
2
0.074
2
14
)
]
= 97.5090
Accrued coupon amount = 5,000,000 × 0.068 ×
TIME CALC
28.091997 DATE1
14.111997 DATE2 360D
28.031998 DATE2 DAYS
14.111997 DATE1 DAYS
46
= 43,444.44
360
(30/360 days accrued coupon)
(ACT/ACT days in coupon period)
(ACT/ACT days to next coupon)
.074 ENTER 2 ÷ 1 + 14 ■ ∧ ■ 1/x
.068 ENTER 2 ÷ +
.068 ENTER .074 ÷ +
.074 ENTER 2 ÷ 1 + 14 ■ ∧ .074 x .068 ■ xy ÷ –
100 ×
.074 ENTER 2 ÷ 1 +
134 ENTER 181 ÷ ■ ∧ ÷
(Dirty price)
6.8 ENTER 46 x 360 ÷
(Accrued coupon)
–
(Clean price)
44. The yield is 7.7246%. If you use the HP calculator’s bond functions, it is
again necessary to make an adjustment for the fact that the price / yield
calculation is on a 30/360 basis but the accrued coupon is on an
ACT/365 basis as follows:
129
• Calculate the correct accrued interest: 8.3 × 365 = 2.933425
• Add to the clean price to give the correct dirty price:
102.48 + 2.933425 = 105.413425
290
11 · Hints and Answers to Exercises and Practice Exam
• Calculate the accrued coupon as if it were on a 30/360 basis:
8.3 × 127 = 2.928056
360
• Subtract from the dirty price to give an adjusted clean price:
105.413425 – 2.928056 = 102.485369
FIN BOND
TYPE 360 ANN EXIT
20.101997 SETT
13.062003 MAT
8.3 CPN%
EXIT EXIT TIME CALC
13.061997 DATE1
20.101997 DATE2 DAYS
365 ÷ 8.3 x
102.48 +
EXIT EXIT FIN BOND
MORE ACCRU
–
PRICE
YLD%
(ACT/365 days accrued coupon)
(Accrued coupon)
(Dirty price]
(Accrued coupon on 30/360 basis)
(Clean price assuming 30/360 accrued)
45. The last quasi-coupon date was 27 March 1998
The next quasi-coupon date is 27 September 1998
The quasi-coupon period is 184 days
The fraction of a period (ACT/ACT) from settlement to 27 September
yo
1998 is œ–
^®.
Therefore 65.48 =
Therefore i =
[(
100
69
(1 + 2i )(184+15)
1
]
69 +15
100 (184
) – 1 × 2 = 5.5845%
65.48
)
100 ENTER 65.48 ÷
69 ENTER 184 ÷ 15 + ■ 1/x ■ ∧
1–2×
OR
FIN BOND
TYPE A/A SEMI EXIT
291
Mastering Financial Calculations
20.071998 SETT
27.032006 MAT
0 CPN%
MORE 65.48 PRICE
YLD%
46.
8.0%
1 – 0.08 ×
97
360
× 365 = 8.29%
360
.08 ENTER 97 × 360 ÷ 1 – +/- 8 ■ xy ÷ 365 × 360 ÷
47. With the same notation as before, the number of days from purchase to
maturity is 205:
–
205
+
365
i=
(
2
( )
205
365
+2
(
)
205
365
– 21 ×
(
205
365
((
–
∑-q
1
205
1 – 0.08 × 360
1
2
)
))
–1
)
= 8.46%
.08 ENTER 205 x 360 ÷ 1 – +/- ■ 1/x 1 –
205 ENTER 365 ÷ .5 – × 2 ×
205 ENTER 365 ÷ ■ x2 + ■ x
205 ENTER 365 ÷ –
205 ENTER 365 ÷ .5 – ÷
48. The same equation as in the previous question can be manipulated to give:
(
D = 360 1 –
days
i2 ×
=
(
2
(
360
1–
205
(0.09)2 ×
days
365
–
1
2
) + 2i ×
+2
)
2
(
205
365
–
1
2
) + 2 × 0.09 ×
= 8.49%
205 ENTER 365 ÷ .5 – .09 × .09 ×
2 ENTER .09 × 205 × 365 ÷ +
2+
2 ■ xy ÷ 1 – +/360 × 205 ÷
292
days
365
205
365
+2
)
11 · Hints and Answers to Exercises and Practice Exam
49. The HP bond calculation function cannot be used for a bond with stepped
coupons. The easiest method is to work from first principles, as follows:
• Discount the final cashflow of 105.75 to a value one year earlier:
105.75
= 100.4846
1.0524
• Add the coupon cashflow of 5.50 paid then and discount back a further year:
100.4846 + 5.50
= 100.7075
1.0524
• Repeat the process back to 3 March 1998:
100.7075 + 5.25
= 100.6818
1.0524
100.6818 + 5.00
= 100.4198
1.0524
100.4198 + 4.75
= 99.9333
1.0524
99.9333 + 4.5 = 104.4333
• Discount the value of 104.4333 back to settlement date (112 days on a
30/360 basis) to give the current dirty price:
104.4333
112
= 102.7870
(1.0524)360
• Subtract the accrued interest (248 days on a 30/360 basis) to give the
clean price:
102.7870 – 4.5 ×
248
= 99.69
360
105.75 ENTER 1.0524 ÷
5.5 + 1.0524 ÷
5.25 + 1.0524 ÷
5 + 1.0524 ÷
4.75 + 1.0524 ÷
4.5 +
1.0524 ENTER 112 ENTER 360 ÷ ■ ∧ ÷
248 ENTER 360 ÷ 4.5 x –
(Dirty price)
(Clean price)
50. Because bond price / yield formulas generally assume a redemption
amount of 100, a straightforward method is to scale down every cashflow by the same factor to correspond to a redemption amount of 100.
100
98
Thus for each (1.10
) nominal amount of bond, the price paid is (1.10
), the
293
Mastering Financial Calculations
3.3
coupons paid are (1.10
) and the redemption payment is 100. This gives a
yield of 4.39%.
Using the HP bond function, however, it is possible to achieve the answer
more simply by entering 110 as the “call value.”
FIN BOND TYPE 360 ANN EXIT
8.121997 SETT
20.092007 MAT
3.3 ENTER 1.1 ÷ CPN%
98 ENTER 1.1 ÷ MORE PRICE
YLD%
OR
FIN BOND TYPE 360 ANN EXIT
8.121997 SETT
20.092007 MAT
3.3 CPN%
110 CALL
MORE 98 PRICE
YLD%
(Remember afterwards to reset the call value to 100 for future calculations!)
All-in initial cost = 98 + 3.3 ×
78
= 98.715
360
All-in sale proceeds = 98.50 + 3.3 ×
85
= 99.279
360
99.279
360
– 1) ×
= 29.39%
( 98.715
7
99.279
Effective rate of return (ACT/365) = (
– 1 = 34.60%
98.715 )
Simple rate of return (ACT/360) =
365
7
3.3 ENTER 85 x 360 ÷ 98.5 +
3.3 ENTER 78 x 360 ÷ 98 + ÷ STO 1
1 - 360 x 7 ÷
RCL1 365 ENTER 7 ÷ ■ ∧ 1 -
(Simple rate)
(Effective rate)
51. a. Last coupon 7 June 1997
ACT/365 basis: 51 × 7.5 = 1.047945
365
b. Last coupon 15 February 1997
Next coupon 15 August 1997 (181-day coupon period)
ACT/ACT basis: 163 × 5.625 = 2.532804
362
294
11 · Hints and Answers to Exercises and Practice Exam
c. Last coupon 26 October 1996
30/360 basis: 272 × 6.25 = 4.722222
360
d. Last coupon 25 October 1996
Next coupon 25 October 1997 (365-day coupon period)
ACT/ACT basis: 276 × 7.25 = 5.482192
365
e. Last coupon 20 March 1997
ACT/365 basis: 130 × 3.00 = 1.068493
365
f. Last coupon 15 November 1996
30/360 basis: 253 × 7.00 = 4.919444
360
g. Last coupon 28 October 1996
Next coupon 28 October 1997 (365-day coupon period)
ACT/ACT basis: 273 × 8.80 = 6.581918
365
h. Last coupon 1 February 1997
30/360 basis plus 1 extra day: 178 × 9.50 = 4.697222
360
52. The futures price would be less than 100. Between now and delivery of the
futures contract, the purchaser of the futures contract is earning a lower
yield on the money market than the coupon he would earn by buying the
bond in the cash market. The price is therefore lower to compensate.
53. Payment for the bond purchased by the futures seller to hedge himself is
made on 25 April. Coupon on the purchase of the bond is accrued for
112 days. Therefore:
Accrued coupon now = 7.375 × 112 = 2.294444
360
Delivery of the bond to the futures buyer would require payment to the
futures seller on 10 September. The futures seller must therefore fund his
position from 25 April to 10 September (138 actual days) and coupon on
the bond on 10 September will be accrued for 247 days. Therefore:
Accrued coupon then = 7.375 × 247 = 5.060069
360
295
Mastering Financial Calculations
Theoretical futures price =
(
)
138
(106.13 + 2.294444) × 1 + 0.0335 × 360
– 5.060069
= 93.14
1.1247
7.375 ENTER 112 x 360 ÷
106.13 +
.0335 ENTER 138 x 360 ÷ 1 + x
7.375 ENTER 247 x 360 ÷
– 1.1247 ÷
54. Implied repo rate =
(Accrued coupon now)
(Accrued coupon in September)
× 1.1247) + 5.060069
360
– 1] ×
= 3.24%
[(93.10(106.13
+ 2.29444)
138
93.1 ENTER 1.1247 × 5.060069 +
106.13 ENTER 2.294444 + ÷
1 – 360 x 138 ÷
55. Assume to start with that the implied repo rate is higher than the actual
current repo rate.
Cost of buying CTD bond per DEM 100 nominal is (clean price +
accrued coupon) = DEM (102.71 + 3.599) = DEM 106.309
Total borrowing (principal + interest) to be repaid at the end
(
= DEM 106.309 × 1 + 0.068 ×
)
24
= DEM 106.790934
360
Anticipated receipt from selling futures contract and delivering bond per
DEM 100 nominal = (futures price × conversion factor) + accrued coupon
= DEM (85.31 × 1.2030) + 4.191 = DEM 106.818930
Profit = DEM (106.818930 - 106.790934) = 0.027996 per DEM 100
nominal
Size of DEM bond futures contract is DEM 250,000 nominal
Therefore face value of bond purchased against each futures contract is
250,000
DEM
= DEM 207,814
1.2030
Therefore profit per futures contract
= DEM 0.027996 × 207,814 = DEM 58.18
100
296
11 · Hints and Answers to Exercises and Practice Exam
56.
Yield (from HP):
Duration:
duration
Modified duration = (1+yield)
:
Accrued coupon (from HP):
Clean price:
Dirty price ( = clean price +
accrued):
Face value:
Total value
price
):
(= face value × dirty100
Bond A
7.92%
4.41
4.09
0.50
88.50
Bond B
7.17%
2.31
2.16
4.80
111.00
Bond C
7.52%
3.61
3.36
5.00
94.70
89.00
10 million
115.80
5 million
99.70
15 million
8.9 million 5.79 million 14.955 million
modified duration of portfolio ≈
=
∑ (modified duration × value)
portfolio value
4.09 × 8.9 + 2.16 × 5.79 + 3.36 × 14.955
= 3.34
8.9 + 5.79 + 14.955
Change in value ≈ – change in yield × modified duration × total value
= –0.001 × 3.34 × 29.645 million = –99,014
57.
Yield (from HP):
Duration:
duration
Modified duration = (1+yield)
:
Accrued coupon (from HP):
Clean price:
Dirty price ( = clean price +
accrued):
Bond A
7.92%
4.41
4.09
0.50
88.50
Bond B
8.92%
7.56
6.94
3.50
107.50
89.00
111.00
For an increase of say 1 basis point in yield, the change in value of bond
A is:
–0.0001 × modified duration of bond A × face value of bond A
×
dirty price of bond A
100
= –0.0001 × 4.09 × 10 million × 0.89 = –3,640
For an increase of 1 basis point in yield, the change in value of bond B is:
–0.0001 × modified duration of bond B × face value of bond B
×
dirty price of bond B
100
297
Mastering Financial Calculations
= –0.0001 × 6.94 × face value × 1.1100 = –0.0007703 × face value
Therefore face value of bond B required for a hedge is
3,640
0.0007703
= 4,725,186
The ratio for using futures to hedge a position in the CTD bond is:
conversion factor
1.2754
=
days
1
+
funding
cost
×
1
+
(
( 0.10 ×
year)
32
360
)
= 1.2642
Therefore notional value of futures required to hedge 10 million in bond
A is:
4,725,186 × 1.2642 = 5,973,580
As each contract has a notional size of 100,000, you need 60 contracts.
58. Bootstrap to create 2-year zero-coupon yield:
Year
0
1
2
–97.700
+9.000
+109.000
Net flows
–89.518
9
+ 1.1
–9.000
+109.000
2-year zero-coupon yield is
(
1
)
109 2
– 1 = 10.35%
89.518
2-year discount factor is 89.518 = 0.8213
109
Bootstrap to create 3-year zero-coupon yield:
Year
0
1
2
3
–90.900
+7.000
+7.000
+107.000
7
+ 1.1
–7.000
+(7 × 0.8213)
–7.000
+107.000
(
1
)
107 3
3-year zero-coupon yield is
– 1 = 10.74%
78.787
3-year discount factor is 78.787 = 0.7363
107
Bootstrap to create 4-year zero-coupon yield:
298
Net flows
–78.787
11 · Hints and Answers to Exercises and Practice Exam
Year
0
–99.400
1
+11.000
2
+11.000
3
+11.000
4 +111.000
11
+ 1.1
+(11 × 0.8213)
–11.000
–11.000
+(11 × 0.7363)
Net flows
–72.266
–11.000
+111.000
4-year zero-coupon yield is
1
4
111
( 72.266
) – 1 = 11.33%
4-year discount factor is 72.266 = 0.6510
111
1-year discount factor is
1
= 0.9091
1.10
1 year v 2 year forward-forward =
1-year discount factor
–1
2-year discount factor
=
0.9091
– 1 = 10.69%
0.8213
2 year v 3 year forward-forward =
0.8213
– 1 = 11.54%
0.7363
3 year v 4 year forward-forward =
0.7363
– 1 = 13.10%
0.6510
59.
a Strip to create zero-coupon yields:
2-year: (1.08 × 1.0824)-q∑ – 1 = 8.12%
3-year: (1.08 × 1.0824 × 1.09)q-́ – 1 = 8.41%
4-year: (1.08 × 1.0824 × 1.09 × 1.095)-q® – 1 = 8.68%
Discount factors are:
1-year:
1
= 0.9259
1.08
2-year:
1
= 0.8554
(1.0812)2
3-year:
1
= 0.7849
(1.0841)3
4-year:
1
= 0.7168
(1.0868)4
If i is the 2-year par yield, then:
i × 0.9259 + (1 + i) × 0.8554 = 1
Therefore i =
1 – 0.8554
= 8.12%
0.9259 + 0.8554
299
Mastering Financial Calculations
Similarly, 3-year par yield =
1 – 0.7849
= 8.38%
0.9259 + 0.8554 + 0.7849
4-year par yield =
1 – 0.7168
0.9259 + 0.8554 + 0.7849 + 0.7168
= 8.63%
b. Discounting each cashflow at a zero-coupon yield, the price of the 4-year
bond is:
(12 × 0.9259) + (12 × 0.8554) + (12 × 0.7849) + (112 × 0.7168) = 111.076
Using the TVM function of the calculator, this gives the yield to maturity
as 8.61%.
60. Bootstrap using middle rates to create 18-month discount factor:
Time
Net flows
0
–100
6
+8.85 × 182
360
12
+8.85 × 183
360
18
+100 + 8.85 × 183
360
+8.85 × 183
360
+8.85 × 182
360
(1 + 0.0875 × 365
)
360
(1 + 0.0865 × 182
)
360
–91.581
–8.85 × 182
360
–8.85 × 183
360
+104.499
18-month discount factor is
91.581
= 0.8764
104.499
Bootstrap to create 24-month discount factor:
Time
Net flows
+8.95 × 183
× 0.8764
360
0
–100
6
+8.95 × 182
360
12
+8.95 × 183
360
18
+8.95 × 183
360
24
+100 + 8.95 × 182
360
+8.95 × 182
360
(1 + 0.0875 × 365
) (1 + 0.0865 × 182
)
360
360
–87.499
–8.95 × 182
360
–8.95 × 183
360
–8.95 × 183
360
+104.525
24-month discount factor is
18 v 24 FRA =
+8.95 × 183
360
[
1
0.8371
1
0.8764
87.499
= 0.8371
104.525
]
– 1 × 360 = 9.24%
183
Assuming FRA is benchmarked against LIBOR, add .05% (half the
bid–offer spread) to this calculation: 9.29%
300
11 · Hints and Answers to Exercises and Practice Exam
61. Remember that Eurosterling is on a 365-day basis and EuroDeutschemarks
are on a 360-day basis.
Middle swap price = 2.5585 ×
– 0.13 × 365
(0.09 × 365
360
365 )
)
(1 + 0.13 × 365
365
= –0.0877
= 877 points Deutschemark premium
.09 ENTER 365 × 360 ÷ .13 –
1.13 ÷ 2.5585 ×
62. a. 5.1020 ÷ 1.5145 = 3.3688
5.1040 ÷ 1.5140 = 3.3712
Spot DEM/FRF is 3.3688 / 3.3712.
Customer buys FRF at 3.3688.
b. 1.9490 × 5.1020 = 9.9438
1.9500 × 5.1040 = 9.9528
Spot GBP/FRF is 9.9438 / 9.9528.
Customer sells GBP at 9.9438.
c. 5.1020 / 5.1040
246 /
259
5.1266 / 5.1299 USD/FRF 3 months forward outright.
d. 1.9490 / 1.9500
268 /
265
1.9222 / 1.9235 GBP/USD 3 months forward outright.
e. 1.9222 × 5.1266 = 9.8544
1.9235 × 5.1299 = 9.8674
3 months forward outright GBP/FRF is 9.8544 / 9.8674
GBP interest rates are higher than FRF rates because sterling is
worth fewer FRF forward than spot.
f. 1.5140 / 1.5145
29 /
32
1.5169 / 1.5177 USD/DEM 3 months forward outright
5.1266 ÷ 1.5177 = 3.3779
5.1299 ÷ 1.5169 = 3.3818
3 months forward outright DEM/FRF is 3.3779 / 3.3818
FRF interest rates are higher than DEM rates because the DEM is
worth more FRF forward than spot.
g. Outright 3.3779 / 3.3818
Spot
3.3688 / 3.3712
91 /
106 DEM/FRF 3 months forward swap.
301
Mastering Financial Calculations
63. a. 5.1020
18
/ 5.1040
/
20
Spot
S/W
5.1038
/ 5.1060
USD/FRF 1 week outright.
b. 5.1020
/ 5.1040
Spot
2.3 /
2.9 T/N
5.10171 / 5.10377 USD/FRF tomorrow outright.
Before spot, use the opposite side of the forward swap price.
c. 5.1020
/ 5.1040
Spot
2.3 /
2.9 T/N
2.0 /
2.5 O/N
5.10146 / 5.10357 USD/FRF today outright.
Customer buys FRF value today at 5.10146.
d. 1.9490
/ 1.9500
Spot
3.5 /
3.3 T/N
10.6 /
10.1 O/N
1.95034 / 1.95141 GBP/USD today outright.
Customer buys GBP value today at 1.95141.
e. 96 / 94
23 / 22
1-month swap
1-week swap
74 / 71 1 week against 1 month forward-forward swap GBP/USD.
Customer “buys and sells” GBP at 74.
The forward-forward price is the difference between opposite sides of
the prices. The bank buys the base currency on the left on the far date.
f. 96 / 94 1-month swap
3.5/ 3.3 T/N swap
99.5/ 97.3 Tomorrow against 1 month forward-forward swap.
Customer “buys and sells” GBP at 99.5.
64. Calculate the USD/FRF and USD/NOK forward outrights as usual:
USD/FRF
6.26965 / 6.27175
6.2385 / 6.2425
6.2145 / 6.2205
(tomorrow outright)
(3-month outright)
(6-month outright)
USD/NOK
6.76195 / 6.76398
6.7605 / 6.7655
6.7670 / 6.7740
Calculating the cross-rate spot, outrights and swaps as usual gives:
(spot)
(tomorrow outright)
(3-month outright)
(6-month outright)
NOK/FRF
0.92689 / 0.92746
0.92692 / 0.92751
0.9221 / 0.9234
0.9174 / 0.9192
(Remember to “reverse” the T/N swap price)
302
(T/N swap)
0.5 / 0.3
(3-month swap) 48 / 40
(6-month swap) 95 / 82
11 · Hints and Answers to Exercises and Practice Exam
a. 3 months v 6 months forward-forward price is:
(95 – 40) / (82 – 48) – i.e. 55 / 34
The bank buys the base currency (in this case NOK) on the far date on
the left side. You therefore deal on a price of 55.
b. Tomorrow v 3 months forward-forward price is:
(48 + 0.5) / (40 + 0.3) - i.e. 48.5 / 40.3
Your customer wishes to buy NOK on the far date, which is the right
side. You therefore deal on a price of 40.3. This can be broken down
into the two swaps as follows. First, between tomorrow and spot, he is
“selling and buying” the base currency (NOK); as the bank is selling the
base currency on the far date, this is the right side (minus 0.3). Second,
between spot and 3 months, he is again “selling and buying” the base
currency (NOK); as the bank is selling the base currency on the far date,
this is again the right side (minus 40 points). The combination is (minus
0.3 points) plus (minus 40 points) = (minus 40.3 points).
65. a. Today is Friday 19 April.
Spot is Tuesday 23 April.
Spot-a-week is Tuesday 30 April.
1 month is Thursday 23 May.
2 months is Monday 24 June (23 June is a Sunday).
Number of days from 23 May to 24 June is 32.
Number of days from 23 May to 3 June is 11.
Therefore price for 3 June is:
1-month price + (qq
_
´∑ × difference between 2-month price and 1-month
price)
USD/FRF
5.2590
25 / 23
133 / 119
(Middle spot)
(Swap to 30 April)
(Swap to 3 June)
GBP/USD
1.9162
11 / 9
69 / 62
Your customer is “buying and selling” FRF (in that order). The bank
buys the variable currency on the far date on the right side. In the
USD/FRF swap prices, you therefore need the right side of “133 / 119”
but the left side of “25 / 23”. In the GBP/USD prices, however, the customer is “selling and buying” (in that order) the base currency GBP
(because GBP is quoted “direct”). Therefore you again need the right
side of “69 / 62” and the left side of “11 / 9”.
The GBP/FRF prices you need are therefore as follows:
(outright value 3 June):
(5.2590 – 0.0119) × (1.9162 – 0.0062) = 10.0220
(outright value 30 April):
(5.2590 – 0.0025) × (1.9162 – 0.0011) = 10.0667
– 0.0447
303
Mastering Financial Calculations
The forward-forward price where the customer can buy FRF value
30 April and sell FRF value 3 June is therefore 447 points GBP discount – that is 447 points in the customer’s favour (because he/she is
selling on the far date the currency which is worth more in the future).
b. For short dates you need to combine the swaps, because you are
rolling an existing contract from today to tomorrow, from tomorrow
to the next day and from then until a week later. The total swap from
today to a week after spot is therefore:
O/N
T/N
S/W
– 0.4
– 1.5
– 11
– 12.9
/
/
/
/
+ 0.1
–1
–9
– 9.9
Your customer needs to sell GBP / buy USD on the far date. The bank
buys the base currency (GBP) on the far date on the left, at 12.9 points
GBP discount – that is, 12.9 points against the customer.
OR
Your customer needs to “buy and sell” GBP (in that order) today
against tomorrow. The bank buys the base currency (GBP) on the far
date on the left side. The prices are all bigger on the left – GBP is at a
discount, worth less in the future. As the customer is selling GBP on
the far date, 0.4 points will be against him.
Similarly, he needs to “buy and sell” GBP tomorrow against spot –
another 1.5 points against him. He also needs to “buy and sell” GBP
spot against 1 week – another 11 points against him. The total swap
price will therefore be 0.4 + 1.5 + 11 = 12.9 points against him.
c. Spot:
1.9157
T/N:
1.5
Outright value tomorrow: 1.9158
O/N:
Outright value today:
–0.4
1.91579
/
67
/
1
/1.91685 (“reverse” the short-date)
/
+0.1
/1.91689 (“reverse” the short-date)
Deal at 1.91689
66. a. USD/ITL
Spot:
Swap:
1633.25 / 1634.25
22.37 /
22.87
Outright:
1655.62 / 1657.12
The bank sells the base currency (USD) on the right side, so the outright price quoted is 1657.12.
The USD is worth more in the future and the ITL is worth less, so the
ITL is at a discount.
304
11 · Hints and Answers to Exercises and Practice Exam
b. The current interest rates are consistent with the current swap price.
Assume that the expected changes do happen, and calculate the effect
on the forward outright price, using middle prices for the comparison.
After the rates have moved, they will be as follows:
Spot rates
USD/DEM 1.6150
DEM/ITL 1005
}
USD/ITL = 1.6150 × 1005 = 1623.08
Interest rates
USD
4.50% / 4.625% (middle: 4.5625%)
ITL
9.00% / 9.25% (middle: 9.125%)
Middle swap price = 1623.08 ×
(0.09125 – 0.045625) × 180
360
(1 + 0.045625 × 180
)
360
= 36.20
The outright middle rate would therefore be 1623.08 + 36.20
= 1659.28
This is slightly worse than the current outright middle rate of
USD/ITL 1656.37, so it is not worth waiting according to these
expectations; the improvement in the spot rate has been more than
offset by the movement in the swap rate – even though the swap is for
a slightly shorter period.
The movement in the swap price could be approximated as follows:
Interest rate differential widens by 1.75%; period is half a year.
Therefore swap price moves by approximately:
spot × 0.0175 × q-∑ = 14.3
The customer is selling the currency which is at a discount (worth less
in the future) and the discount is increasing, so this movement in the
swap price of approximately 14.3 must be against him/her. He/she
must therefore expect a spot movement of at least this much in his/her
favour for it to be worthwhile waiting.
67. Invest DEM 15 million for 91 days
Investor buys and sells USD (sells and buys DEM) spot against 3 months
at 1.6730 and 1.6557
Investor’s cashflows spot:
invest DEM 15 million
sell DEM 15 million and buy USD 8,965,929.47 at 1.6730
invest USD 8,965,929.47 in USD CP
CP yields LIBOR + 4 bp = 8.375% + 0.04% = 8.415%
305
Mastering Financial Calculations
Total proceeds at maturity of CP
(
= USD 8,965,929.47 × 1 + 0.08415 × 91
360
= USD 9,156,646.00
)
Investor sells USD 9,156,646.00 forward at 1.6557 against DEM
15,160,658.77
Investor’s cashflows after 3 months:
receive USD 9,156,646.00 from CP
sell USD 9,156,646.00
buy DEM 15,160,658.77
Overall DEM return =
360
– 1) ×
= 4.24%
( 15,160,658.77
15,000,000.00
91
This is effectively DEM LIBOR minus 1 bp. Assuming that the investor’s
alternative would be a deposit at DEM LIBID, the covered interest arbitrage is more attractive.
Note that, in practice, the investor could probably not buy USD commercial paper with a face value of USD 9,156,646 (the total maturity
proceeds for CP are the same as its face value); he would instead need to
purchase a round amount but this would not affect the rate of return.
Note also that the amounts dealt on each leg of the swap are mismatched. The bank would therefore generally wish to base the prices on
the left side of the spot price (rather than the middle) because that is the
“correct” side for a forward outright for the mismatch difference.
15,000,000 ENTER 1.6730 ÷
.08415 ENTER 91 × 360 ÷ 1 + ×
1.6557 ×
15,000,000 ÷ 1 – 360 × 91 ÷
(Amount invested)
(Maturity proceeds in USD)
(Maturity proceeds in DEM)
(Rate of return)
Alternatively, using the formula for covered interest arbitrage:
variable currency rate =
variable year
– 1] ×
[(1 + base currency rate × basedaysyear ) × outright
spot
days
=
1.6557
91
360
× (1 + 0.08415 ×
– 1] ×
= 4.24%
[ 1.6730
360 )
91
.08415 ENTER 91 × 360 ÷ 1 + 1.6557 × 1.6730 ÷ 1 – 360 × 91 ÷
68. Action now
(i) Arrange FRA 3 v 9 on a notional 6-month borrowing
1,000,000
of USD
= USD 165,016.50
6.0600
(
306
)
11 · Hints and Answers to Exercises and Practice Exam
Assuming FRA settlement at the end of 9 months (rather than dis
counted after 3 months as is conventional), the total notional repay
ment on this borrowing would be:
(
USD 165,016.50 × 1 + 0.0575 ×
)
182
= USD 169,813.44
360
(ii) Convert this notional borrowing from USD to SEK:
• sell USD 165,016.50 / buy SEK 1,000,000.00 (at 6.0600) for value
3 months forward
• buy USD 169,813.44 / sell SEK 1,050,839.53 (at 6.1882) for value
9 months forward
Action in 3 months’ time
(iii) Assume borrowing of SEK (165,016.50 × 6.2060)
= SEK 1,024,092.40 for 6 months
Total repayment will be:
(
SEK 1,024,092.40 × 1 + 0.1062 ×
)
182
= SEK 1,079,075.92
360
(iv) Convert this borrowing to a notional USD borrowing to match (i):
• buy USD 165,016.50 / sell SEK 1,024,092.40 (at 6.2060) for
value spot
• sell USD 170,022.00 / buy SEK 1,078,857.60 (at 6.3454) for value
6 months forward
(USD 170,022.00 is the total repayment which would be due on a 6month loan of USD 165,016.50 taken at the rate of 6.00% now
prevailing.)
Settlement at the end of 9 months
Receive FRA settlement of USD 165,016.50 × (0.06 – 0.0575) ×
182
360
= USD 208.56
After 3 months:
After 9 months:
+
–
+
+
Total flows
SEK
1,024,092.40
(iii)
1,024,092.40
(iv)
1,000,000.00
(ii)
1,000,000.00
– 1,079,075.92
+ 1,078,857.60
– 1,050,839.53
– 1,051,057.85
(iii)
(iv)
(i)
(ii)
USD
+ 165,016.50
– 165,016.50
–
– 170,022.00
+
208.56
+ 169,813.44
–
307
Mastering Financial Calculations
Effective cost is
51,057.85
360
×
= 10.10%
1,000,000 (273 – 91)
Note that, in practice, the USD FRA settlement would be received after 3
months on a discounted basis but could then be invested until 9 months.
If this investment were at only 5.87% (LIBID), the final result would be
changed very slightly.
69. The USD cashflows net to zero both spot and forward.
(a)
(b)
DEM cashflows
spot
6 months
–16,510,000
+16,350,000
+16,495,000
–16,325,000
Net:
–
15,000
NPV = –DEM15,000 + DEM
+
25,000
25,000
= DEM9,443.90
(1 + 0.045 × 182
)
360
70. a. DEM cashflows:
3 months
+ 10,164,306
6 months
+ 10,000,000
12 months
– 10,000,000
– 10,709,722
Valuation in USD at current forward exchange rates:
+ 5,634,316
+ 5,528,527
– 11,397,756
New rates after USD/DEM moves from 1.80 to 2.00:
USD/DEM
2.0000
2.0045
2.0098
2.0189
Spot:
3 months:
6 months:
12 months:
USD%
DEM%
6.5
6.5
7.0
7.4
7.5
8.0
Valuation in USD at new forward rates:
3 months
+ 5,070,744
6 months
+ 4,975,619
12 months
– 10,257,924
Change in valuation in USD:
–
563,572
–
552,908
+ 1,139,832
Total net profit = USD 23,352
b.The profits / losses discounted to spot become:
–
308
3 months
554,462
–
6 months
535,317
12 months
+ 1,064,297
11 · Hints and Answers to Exercises and Practice Exam
Total net present value of profits / losses: – USD 25,482
It is possible to hedge this exposure by a spot transaction of the net present value of the forward DEM positions:
Actual DEM
cashflows:
Discounted
to PV:
Total NPV:
3 months
6 months
12 months
+ 10,164,306
+ 10,000,000
– 20,709,722
+ 9,977,668
+
456,392
+ 9,634,685
– 19,155,961
This NPV is the amount of DEM which should be sold to achieve a
hedge. Suppose that this had been done spot at 1.80. A move to a spot
rate of 2.00 would then have produced a profit on the hedge of:
456,392 456,392
USD
–
= USD 25,355
1.80
2.00
(
)
Allowing for rounding differences, this would offset the loss shown above.
71. As you will be receiving fixed payments under the swap, the spread over
treasuries will be 80 basis points (rather than 90). The receipt will therefore be 9.80% on a semi-annual bond basis.
Your cashflows are therefore:
pay:
8.90% annual money market ≈ 8.71% semi-annual money market
receive: 9.80% semi-annual bond
= 9.67% semi-annual money market
pay:
LIBOR semi-annual money market
net pay:
LIBOR – 96 basis points
This answer does not discount the cashflows precisely.
72. a. Convert the futures price to implied forward-forward interest rates
and then create strips to calculate the effective (annual equivalent)
zero-coupon swap rates for each quarterly period up to 18 months:
18-month rate =
[
91 × 1 + 0.0659 × 91 ×
(1 + 0.0625 × 360
) (
)
360
365
547
91 × 1 + 0.0737 × 92 ×
(1 + 0.0716 × 360
) (
)
360
(
) (
)
1 + 0.0762 × 91 × 1 + 0.0790 × 91
360
360
]
– 1 = 7.4470%
309
Mastering Financial Calculations
15-month rate:
[
91 × 1 + 0.0659 × 91
(1 + 0.0625 × 360
) (
360)
(
) (
(
)
]
)
× 1 + 0.0716 × 91 × 1 + 0.0737 × 92
360
360
× 1 + 0.0762 × 91
360
365
456
– 1 = 7.2868%
12-month rate =
[
[
91 × 1 + 0.0659 × 91
(1 + 0.0625 × 360
) (
)
360
(
) (
)
× 1 + 0.0716 × 91 × 1 + 0.0737 × 92
360
360
9-month rate =
91 × 1 + 0.0659 × 91
(1 + 0.0625 × 360
) (
360)
(
)
× 1 + 0.0716 × 91
360
[(
) (
[(
)]
]
]
– 1 = 7.1214%
365
273
– 1 = 6.9325%
91 × 1 + 0.0659 × 91
6-month rate = 1 + 0.0625 ×
360
360
3-month rate = 1 + 0.0625 × 91
360
365
91
)]
365
182
– 1 = 6.6699%
– 1 = 6.4891%
b. The 18-month par swap rate on a quarterly money market basis is
then i, where the NPV of a par investment with quarterly money
market coupon i is itself par:
1=
91
i × 360
91
(1.064891)365
+
91
i × 360
+
182
(1.066699) 365
91
i × 360
456
(1.072868)365
+
91
i × 360
+
273
(1.069325)365
+
92
i × 360
365
(1.071214)365
91
1 + i × 360
547
(1.074470)365
This gives 1 = 0.248846i + 0.244769i + 0.240418i + 0.238566i +
0.231514i + 0.226981i + 0.897948
Therefore i = 7.13%
73. a. Discount the USD cashflows at 9% to an NPV ( = USD 102.531
million). Convert to sterling at the current spot exchange rate ( = GBP
66.149 million). Apply 11% to this amount to create a stream of
310
11 · Hints and Answers to Exercises and Practice Exam
equivalent sterling flows (= GBP 7.276 million per year plus GBP
66.149 million at maturity). All flows below are in millions:
Year 1:
Year 2:
Year 3:
(i)
Remaining bond
cashflows
USD
–10
–10
–10
–100
NPV:
(ii)
Equivalent of (i)
discounted at 9%
USD
–9.174
–8.417
–7.722
–77.218
(iii)
Swap receipts
(iv)
Swap payments
USD
+10
+10
+10
+100
GBP
–7.276
–7.276
–7.276
–66.149
–102.531
Your total cashflows are (i), (iii) and (iv); your net cashflows are (iv).
b. To calculate the long-dated forward prices, remember that USD money
market rates are on a 360-day basis. The forward rates (assuming
there are actually 365 days in each year) are as follows:
1 year:
1.55 ×
(1 + 0.09 × 365
)
360
= 1.4837
(1 + 0.14 × 365
)
365
2
2 years: 1.55 ×
(1 + 0.085 × 365
)
360
2
(1 + 0.12 × 365
)
365
= 1.4578
3
3 years: 1.55 ×
(1 + 0.08 × 365
)
360
3
(1 + 0.10 × 365
)
365
= 1.4715
At these rates, the cashflows can be converted as follows:
Year 1:
Year 2:
Year 3:
(i)
Remaining bond
cashflows
USD
–10
–10
–110
(iv)
Cashflows converted
at forward rates
GBP
–6.740
–6.860
–74.754
c. You might perhaps prefer the second cashflow profile because it defers
the net cash outflows slightly. Apart from that, you would prefer the
cashflow profile with the lower NPV. Unless the rate of discount is at
least 23.4%, this is the first method.
74. The USD 10 million raised from the bond issue can be converted to CHF
15 million at the spot exchange rate. We therefore need to base the floating side of the swap on CHF 15 million:
311
Mastering Financial Calculations
Year
1
2
3
4
5
Bond cashflows
– $ 650,000
– $ 650,000
– $ 650,000
– $ 650,000
– $ 10,650,000
Swap cashflows
+ $ 650,000
+ $ 650,000
+ $ 650,000
+ $ 650,000
+ $ 10,650,000
– (LIBOR – i) on CHF 15 mln
– (LIBOR – i) on CHF 15 mln
– (LIBOR – i) on CHF 15 mln
– (LIBOR – i) on CHF 15 mln
– (LIBOR – i) on CHF 15 mln
– CHF 15 mln
The NPV of the USD flows in the swap (using 6.8%) is 9,876,333. This
is equivalent to CHF 14,814,499 at the spot exchange rate. If i = 0, the
CHF flows in the swap would have an NPV of CHF 15,000,000. In
order for the two sides of the swap to match therefore, the NPV of (i ×
15 million × q-∑ × ´eyt
–
¥π) each six months for 5 years must be (15,000,000 –
14,814,499) = 185,501.
Convert 4.5% per annum to an equivalent rate of 2.225% for a 6monthly period ( 1.045 = 1.02225). Then, using the TVM function of an
HP calculator:
N = 10, I%YR = 2.225, PV = 185,501, FV = 0 gives PMT = 20,895
eyt
You therefore need 15,000,000 × i × q-∑ × ´–
¥π = 20,895. This gives i =
0.27%. You can therefore achieve (LIBOR – 27 basis points) in CHF.
75. The remaining cashflows are as follows:
Date
Swap
25 May 1998:
USD
+10m × 8%
–15 m × L1 × 184
360
25 Nov 1998:
25 May 1999:
DEM
–15 m × 5.3% × 181
360
+10 m × 8%
+10 m
–15 m × L2 × 181
360
–15 m
where L1 is LIBOR from 25 May 1998 to 25 November 1998
L2 is LIBOR from 25 November 1998 to 25 May 1999
Without upsetting the NPV valuation, add the cashflows for a DEM 15
million “FRN” which starts on 25 May 1998, matures on 25 May 1999
and pays LIBOR semi-annually. The resulting cashflows will then be:
Date
25 May 1998:
“FRN”
Net DEM
USD
Swap
DEM
DEM
cashflows
+10 m × 8%
–15 m × 5.3% × 181
360
–15 m
–15 m × (1 +5.3% × 181
360)
–15 m × L1 × 184
360
+15 m × L1 × 184
360
+10 m × 8%
–15 m × L2 × 181
360
+15 m × L2 × 181
360
+10 m
–15 m
+15 m
25 Nov 1998:
25 May 1999:
312
11 · Hints and Answers to Exercises and Practice Exam
These cashflows can be valued using the discount factors to give:
USD (800,000 × 0.9850 + 10,800,000 × 0.9300)
– DEM (15,399,708 × 0.9880)
= USD 10,832,000 - DEM 15,214,912
Converted at 1.65 spot, this gives an NPV of USD 1,610,841
76. Receive 99.00 at the start, and transact a par swap based on 100. The
bond and swap cashflows are then as follows:
Date
Now:
Bond
+99
Swap
–100 × LIBOR × 12 × 365
360
6 months:
1 year:
–100 × LIBOR × 12 × 365
360
+100 × 7.5%
–7
112 years:
2 years:
–100 × LIBOR × 12 × 365
360
–100 × LIBOR × 12 × 365
360
+100 × 7.5%
–7
212 years:
3 years
–100 × LIBOR × 12 × 365
360
–100 × LIBOR × 12 × 365
360
+100 × 7.5%
–100 –7
You can provide a par / par liability swap based on 100, by eliminating,
you need to eliminate the uneven fixed cashflows of – 1 (= 99 – 100) now
and + 0.5 (= – 7 + 7.5) each year. Discounting at 7.5%, these cashflows
have an NPV of:
– 1 + 0.5 + 0.5 2 + 0.5 3 = 0.3003
1.075 (1.075)
(1.075)
You can eliminate these cashflows if you replace them by a series of semiannual cashflows with the same NPV. The rate of discount you are using is
7.5% (annual). You therefore need an interest rate i (money market basis)
such that:
100 × i × 12 × 365
360
(1.075)0.5
+
+
100 × i × 12 × 365
360
(1.075)2
100 × i × 12 × 365
360
(1.075)
+
100 × i × 12 × 365
360
(1.075)2.5
+
+
100 × i × 12 × 365
360
(1.075)1.5
100 × i × 12 × 365
360
(1.075)3
= 0.3003
The solution to this is: i = 0.11%
You can therefore replace the 30/360 annual swap inflows of (100 ×
7.5%) by a combination of 30/360 annual swap inflows of (100 × 7%)
and ACT/360 semi-annual inflows of (100 × 0.11%). This 0.11% can be
deducted from the ACT/360 semi-annual swap outflows of (100 ×
LIBOR) which you already have.
313
Mastering Financial Calculations
The net effect is therefore a par / par liability swap based on an amount
of 100, at (LIBOR – 11 basis points).
77.
Day
1
2
3
4
5
6
7
8
9
10
Price
1.6320
1.6410
1.6350
1.6390
1.6280
1.6300
1.6250
1.6200
1.6280
1.6200
(Difference from mean)2
Relative price change
LN (price change)
1.005515
0.996344
1.002446
0.993289
1.001229
0.996933
0.996923
1.004938
0.995086
0.005500
-0.003663
0.002443
-0.006734
0.001228
-0.003072
-0.003082
0.004926
-0.004926
0.000040
0.000008
0.000011
0.000035
0.000004
0.000005
0.000005
0.000033
0.000017
-0.007380
-0.000820
0.000158
sum:
mean = sum
9
variance = sum
8
standard deviation =
variance
0.000020
0.004444
volatility = annualized standard deviation =
252 × 0.004444 = 7.1%
78. USD put premium expressed in FRF = percentage of USD amount × spot rate
= 1.5% × 5.7550 = 0.086325
USD call premium = USD put premium + PV of (forward - strike)
= 0.086325 +
5.7000 – 5.6000
= 0.18386
(1 + 0.05 × 182
)
360
Converted to percentage of USD amount at spot rate:
0.18386
= 3.19%
5.7550
79. To calculate probabilities of up and down movement
Say there is a probability p of a 2% increase in price and a probability
(1 – p) of a 2% decrease.
Expected outcome after 1 month is:
p × 100 × 1.02 + (1 – p) ×
100
1.02
= 3.960784p + 98.039216
This should equal the outcome of 100 invested at 12% for 1 month:
(
= 100 × 1 +
)
0.12
= 101
12
Therefore 3.960784p + 98.039216 = 101
314
11 · Hints and Answers to Exercises and Practice Exam
Therefore p =
101 – 98.039216
= 0.7475
3.960784
Therefore: probability of increase to 102 is 74.75%
probability of decrease to
100
1.02
is 25.25%
Possible outcomes after three months
p
p
100
100 × 1.02
(1– p)
(1– p)
p
100 ÷ 1.02
100 × 1.02
× 1.02
p
(1– p)
p
100
(1– p)
100 ÷ 1.02
÷ 1.02
100 × 1.02 × 1.02 × 1.02 = 106.1208
with probability
p × p × p = 0.4177
(1– p)
p
(1– p)
100 × 1.02 = 102 with probability
3 × p × p × (1– p) = 0.4233
100 × 1.02 = 98.0392
with probability
3 × p × (1– p) × (1– p) = 0.1430
100 × 1.02 × 1.02 × 1.02 = 94.2322
with probability
(1– p) × (1– p) × (1– wp) = 0.0161
The expected value of the put option at the end of 3 months is therefore:
(101 – 98.0392) × 0.1430 + (101 – 94.2322) × 0.0161 = 0.5324
The premium for the option is therefore the present value of this
expected value:
0.5324
= 0.517
3
(1 + 0.12 × 12
)
315
Mastering Financial Calculations
ANSWERS TO PRACTICE EXAM
Part 1
1. BEF 829,374.89. As there are 40 semi-annual periods, the TVM function
of the calculator requires the interest for a semi-annual period, which is
5.25%.
FIN TVM
40 N
5.25 I%YR
50,000 PMT
0 FV1
PV
2.
7 +
7
+ 107 3
(1 + i) (1 + i)2
(1 + i)
where i is the yield to maturity on an annual basis.
(
3. 10,000,000 × 1 +
0.07
2
) × (1 + 0.075
4 )
4
12
= 14,340,782.87
.07 ENTER 2 ÷ 1 + 4 ■ ∧
.075 ENTER 4 ÷ 1 + 12 ■ ∧ ×
10,000,000 ×
4.
Forward-forward rate =
=
[
[
]
(1 + 0.09 × 275
360)
–1
92
(1 + 0.09 × 360
)
days
(1 + longer rate × year
)
days
(1 + shorter rate × year
)
×
360
183
]
–1 ×
year
days in period
= 8.80%
.09 ENTER 275 x 360 ÷ 1 +
.09 ENTER 92 x 360 ÷ 1 + ÷
1 - 360 × 183 ÷
You would deposit now for only 3 months at 9.00%. Depositing for
9 months now would be theoretically equivalent to depositing now for
3 months and depositing forward-forward from 3 months to 9 months.
As the 3 v 9 rate implied by the current interest rate structure is lower
than your forecast, this would be less advantageous than depositing now
for 3 months and waiting.
316
11 · Hints and Answers to Exercises and Practice Exam
5. Expressed in DEM:
GBP call premium = GBP put premium + PV of (forward – strike)
= 0.01 × 2.6760 +
(2.65 – 2.60)
= 0.0763
91
(1 + 0.04 × 360
)
Therefore, expressed as percentage of GBP amount:
GBP call premium =
0.0763
= 2.85%
2.676
2.65 ENTER 2.60 –
.04 ENTER 91 x 360 ÷ 1 + ÷
.01 ENTER 2.676 × +
2.676 ÷
1
6. a. [(1 + 0.0835)2 – 1] × 2 = 8.183%
1
b. [(1 + 0.0835)365 – 1] × 365 = 8.021%
1.0835 ENTER ■ x 1 – 2 ×
1.0835 ENTER 365 ■ 1/x ■ ∧ 1 – 365 x
7. 98.48. Found by using an HP calculator. It would also be possible to calculate the price by discounting all 30 cashflows to an NPV.
FIN BOND TYPE SEMI EXIT
Enter any date, then SETT
Enter a date 15 years later, then MAT
10 CPN%
MORE 10.2 YLD%
PRICE
8. First interest payment plus reinvestment:
£1,000,000 ×
3
0.062
0.06
× 1+
4
4
(
)
0.062
0.06
× 1+
4
4
(
)
(
)
Second interest payment plus reinvestment:
£1,000,000 ×
2
Third interest payment plus reinvestment:
£1,000,000 ×
0.062
0.06
× 1+
4
4
317
Mastering Financial Calculations
0.062
4
Fourth interest payment:
£1,000,000 ×
Principal amount
£1,000,000
Total:
£1,063,409.00
.06 ENTER 4 ÷ 1 + 3 ■ ∧
.06 ENTER 4 ÷ 1 + 2 ■ ∧ +
.06 ENTER 4 ÷ 1 + +
1 + .062 x 4 ÷
1 + 1,000,000 x
9.
57
(1 + 0.085 × 360
)
365
57
– 1 = 8.94%
.085 ENTER 57 × 360 ÷ 1 + 365 ENTER 57 ÷ ■ ∧ 1 –
10. Converting all to a true yield on a 365-day basis:
a. 7.50%
b. 7.42% ×
365
= 7.523%
360
c.
7.21%
= 7.479%
(1 – 0.0721 × 182
)
365
d.
7.18%
365
×
= 7.554%
182
(1 – 0.0718 × 360) 360
7.42 ENTER 365 × 360 ÷
.0721 ENTER 182 × 365 ÷ 1 – +/- 7.21 ■ xy ÷
.0718 ENTER 182 × 360 ÷ 1 – +/- 7.18 ■ xy ÷ 365 x 360 ÷
The best investment is (d).
11. Create a strip:
91 × 1 + 0.066 × 92 × 1 + 0.068 × 91
[(1 + 0.065 × 360
) (
360) (
360)
× (1 + 0.07 × 91 ) – 1] × 360 = 6.90%
360
365
318
(b)
(c)
(d)
11 · Hints and Answers to Exercises and Practice Exam
.065 ENTER 91 × 360 ÷ 1 +
.066 ENTER 92 × 360 ÷ 1 + x
.068 ENTER 91 × 360 ÷ 1 + x
.07 ENTER 91 × 360 ÷ 1 + x
1 – 360 × 365 ÷
12. a. False. This is only true on a coupon date. On other dates, there is a
slight difference because the accrued interest is based on simple interest
but the price / yield calculation is based on compound interest. Also,
some bonds use different day/year counts for accrued interest and price /
yield calculations.
b. False. It generally has the highest; it is the bond which is most likely to
be able to be used for a cash-and-carry arbitrage and hence to be
financed more cheaply than its implied repo rate.
c. False. The longer the duration, the higher the modified duration and
hence the higher the sensitivity to yield changes.
d. False. If interest rates are negative (which has happened occasionally
in certain markets), the present value is higher than the future value.
(
)
0.0845 2
– 1 = 8.63%, which is better than 8.60%.
2
f. False. The lower the yield, the less the future cashflows are discounted
to an NPV, so the higher the price.
e. False. 1 +
g. False. Out-of-the-money options have zero intrinsic value.
Part 2
Exercise 1
a.
Accrued interest = 8.0 ×
270
= 5.917808
365
Dirty price = clean price + accrued interest
= 107.50 + 5.917808 = 113.417808
Therefore:
113.417808 =
8
8
8
+
+
+
93
93
93
1+
(1 + i)360
(1 + i) 360
(1 + i)2+ 360
8
8
108
+
+
93
93
93
(1 + i)3+ 360
(1 + i)4+ 360
(1 + i)5+ 360
where i = yield to maturity
319
Mastering Financial Calculations
This question is complicated by the fact that the calculation bases for
accrued coupon and price are different. The bond calculation function on
the HP calculator can be set to calculate on either a 30/360 basis or an
ACT/ACT basis, but not a mixture. To make the calculation it is therefore necessary to “fool” the calculator as follows:
• Calculate the actual dirty price based on the true clean price as above:
113.417808
• Calculate what the accrued interest would be on a 30/360 basis:
8.0 ×
267
= 5.933333
360
• Calculate what the clean price would be on this basis:
113.417808 – 5.933333 = 107.484475
• Use the bond function on a 30/360 basis to calculate the yield,
6.274%
TIME CALC
18.091997 DATE1
15.061998 DATE2
DAYS
365 ÷ 8 ×
107.5 +
360D
360 ÷ 8 ×
–
EXIT EXIT
FIN BOND MORE PRICE
MORE TYPE 360 ANN EXIT
15.061998 SETT
18.092003 MAT
8 CPN%
MORE YLD%
(Actual calendar days for accrued interest)
(Accrued interest)
(Dirty price)
(“Equivalent” clean price on a 30/360 basis)
b. Dirty price on purchase is 113.417808
Dirty price on sale is 106.40 + 8.0 ×
Simple rate of return =
=
320
337
= 113.786301
365
sale proceeds
year
– 1) ×
( original
investment
days held
360
– 1) ×
= 1.75%
(113.786301
113.417808
67
11 · Hints and Answers to Exercises and Practice Exam
8 ENTER 337 × 365 ÷ 106.4 +
8 ENTER 270 × 365 ÷ 107.5 +
÷ 1 - 360 x 67 ÷
Effective rate of return =
=
(113.786301
113.417808 )
365
67
(
(Dirty price on sale)
(Dirty price on purchase)
(Rate of return)
sale proceeds
original investment
)
365
days held
–1
– 1 = 1.78%
8 ENTER 337 × 365 ÷ 106.4 +
8 ENTER 270 × 365 ÷ 107.5 +
÷
365 ENTER 67 ÷ ■ ∧ 1 –
c. Futures price =
[
]
days
–
year
(accrued coupon at delivery of futures) – (intervening coupon + interest earned)
conversion factor
[bond price + accrued coupon now] × 1 + i ×
=
35
274
× (1 + 0.05 × 360
(108 + 8.0 × 239
) – (8.0 × 365
)
365)
1.1000
= 97.98
8 ENTER 239 × 365 ÷ 108 +
.05 ENTER 35 × 360 ÷ 1 + x
8 ENTER 274 × 365 ÷ 1.1 ÷
d. The actual futures price is cheaper than the theoretical price. The arbitrage available can therefore be locked in by buying the futures contract
and selling the CTD bond. This requires borrowing the bond through a
reverse repo in order to deliver it to the bond buyer. There is some risk in
this arbitrage, as the bond delivered on maturity of the futures contract
will be the CTD bond at that time, which may not be the same as the
CTD bond now.
Exercise 2
a
Duration is the weighted average life of a series of cashflows, using the
present values of the cashflows as the weights:
Duration =
Σ (PV of cashflow × time to cashflow)
Σ (PV of cashflow)
321
Mastering Financial Calculations
Modified duration is a measure of a bond price’s sensitivity to small
changes in yield.
Approximately:
/
change in bond price
dirty price
change in yield
Modified duration = –
The relationship is:
Modified duration =
duration
yield to maturity
(1 + coupon
frequency )
b. For a zero-coupon bond, duration = maturity = 3 years
Using the HP calculator, the yield of the four-year bond is 15.00%
FIN TVM
4N
114.27 +/- PV
20 PMT
100 FV
I%YR
The bond’s duration is therefore:
1×
20
(1.15)
+2×
20
(1.15)2
+3×
20
(1.15)3
+4×
114.27
120
(1.15)4
= 3.164 years
The zero-coupon bond therefore has the shorter duration.
20 ENTER 1.15 ÷
1.15 ENTER 2 ■ ∧ 20 ■ xy ÷ 2 x +
1.15 ENTER 3 ■ ∧ 20 ■ xy ÷ 3 x +
1.15 ENTER 4 ■ ∧ 120 ■ xy ÷ 4 x +
114.27 ÷
c. Using the HP calculator, the yield of the zero-coupon bond is 12.00%
FIN TVM
3N
71.18 +/- PV
0 PMT
100 FV
I%YR
The modified duration is therefore
3
= 2.68
1.12
For the four-year bond, the modified duration is
322
3.164
= 2.75
1.15
11 · Hints and Answers to Exercises and Practice Exam
d. Approximate change in price of zero-coupon bond is:
–(0.10%) × 2.68 × 71.18 = –0.191
Approximate change in price of other bond is:
–(0.10%) × 2.75 × 114.27 = –0.314
Therefore loss is approximately:
0.314
+ 10 million ×
= 88,700
(30 million × 0.191
100 ) (
100 )
3 ENTER 1.12 ÷
.001 × 71.18 ×
100 ÷ 30,000,000 x
3.164 ENTER 1.15 ÷
.001 × 114.27 ×
100 ÷ 10,000,000 x
+
(Modified duration of first bond)
(Fall in price of first bond)
(Loss on first holding)
(Modified duration of second bond)
(Fall in price of second bond)
(Loss on second holding)
e. Number of contracts to sell =
value of portfolio
100
×
×
size of futures contract dirty price of CTD bond
modified duration of portfolio
conversion factor of CTD
×
delivery
modified duration of CTD
(1 + funding rate × days to futures
)
year
Exercise 3
a. Calculate the 2-year zero-coupon rate by constructing a synthetic 2-year
zero-coupon structure from the 1-year and 2-year rates, by investing for
2 years and borrowing for 1 year as follows:
Now
1 year
2 years
2-year investment
1-year borrowing
Net cashflows
–104.500
8.000
1.05
–96.881
+
+8.000
–8.000
+108.000
+108.000
The 2-year zero-coupon rate is
The 2-year discount factor is
(
108 12
– 1 = 5.583%
98.881
)
96.881
= 0.8970
108
323
Mastering Financial Calculations
Calculate the 3-year zero-coupon rate similarly by constructing a synthetic 3-year zero-coupon structure:
3-year
investment
2-year
zero-coupon
borrowing
1-year
borrowing
Net
cashflows
Now
–98.70
+5.500 × 0.8970
+ 5.500
1.05
–88.528
1 year
+5.500
2 years
+5.500
3 years
+105.500
–5.500
–5.500
+105.500
The 3-year zero-coupon rate is
The 3-year discount factor is
b. 1-year discount factor is
1
3
– 1 = 6.021%
( 105.500
88.528 )
88.528
= 0.8391
105.500
1
= 0.9524
1.05
From the discount factors:
1 year v 2 year forward-forward =
0.9524
– 1 = 6.17%
0.8970
2 year v 3 year forward-forward =
0.8970
– 1 = 6.90%
0.8391
c. Discounting the cashflows of the bond using the discount factors gives a
price of:
12 × 0.9524 + 12 × 0.8970 + 112 × 0.8391 = 116.172
Using the TVM function, this gives a yield to maturity of 5.95%.
d. If i is the 2-year par yield, then:
1 = i × 0.9524 + (1 + i) × 0.8970
Therefore i =
1 – 0.8970
= 5.57%
0.9524 + 0.8970
Similarly the 3-year par yield =
324
1 – 0.8391
= 5.98%
0.9524 + 0.8970 + 0.8391
11 · Hints and Answers to Exercises and Practice Exam
Exercise 4
a. The remaining cashflows are as follows:
– (50 million × 8.5% × 182
+ (50 million × 10% × 360
360)
360)
2 June 1999:
2 December 1999: –
2 June 2000:
–
(50 million × L1 × 183
360)
183
(50 million × L2 × 360) + (50 million × 10% × 360
360)
Where L1 is 6-month LIBOR for 2 June 1999
and L2 is 6-month LIBOR for 2 December 1999
Method 1
In order to value the unknown interest payments consistently with the
discount factors, calculate forward-forward rates as follows:
360
– 1) ×
= 8.85963%
( 0.9885
0.9459
183
0.9459
360
L =(
– 1) ×
= 8.57292%
0.9064
183
L1 =
2
The mark-to-market value of the remaining cashflows is then their NPV:
[–(50 million × 8.5% × 182
360)
]
+ (50 million × 10% × 360
× 0.9885
360)
= 2,818,598
× 0.9459
[–(50 million × 8.85963% × 183
360)]
[–(50 million × 8.57292% × 183
360)
360
+ (50 million × 10% × 360)] × 0.9064
= –2,129,999
= 2,556,999
3,245,598
Method 2
As an alternative to using forward-forward rates, the unknown cashflows can be eliminated by adding an appropriate structure of
cashflows which itself has a zero NPV. The appropriate structure is an
FRN structure as follows:
2 June 1999:
–50 million
2 December 1999:
+(50 million × L1 × 183
360)
2 June 2000:
+(50 million × L2 × 183
360)
+ 50 million
Adding these cashflows to the whole original structure and netting the
result gives the following:
2 June 1999:
–(50 million × 8.5% × 182
+ 50 million × 10% × 360
360) (
360)
–(50 million)
2 June 2000:
+(50 million × 10% × 360
360)
+50 million
325
Mastering Financial Calculations
The NPV of these cashflows can be calculated as before to give
+ 3,245,598
b. Invest 103.50 and transact a par swap based on 100. The bond and swap
cashflows are then as follows:
Date
Now:
Bond
–103.5
Swap
+100 × LIBOR × 12 × 365
360
6 months:
1 year:
+9
–100 × 7.5%
112 years:
2 years:
+100 × LIBOR × 12 × 365
360
+9
–100 × 7.5%
212 years:
3 years
+100 × LIBOR × 12 × 365
360
+100 × LIBOR × 12 × 365
360
+100 × LIBOR × 12 × 365
360
–100 +9
–100 × 7.5%
+100 × LIBOR × 12 × 365
360
In order to create a par / par asset swap, you need to eliminate the
uneven fixed cashflows of –3.5 now and (9 – 7.5) each year. These cashflows have an NPV of:
–3.5 + 1.5 × 0.9300 + 1.5 × 0.8650 + 1.5 × 0.8050 = +0.40
Suppose that a series of semi-annual cashflows of (100 × i × ∑-q ×
the same NPVs. This means that:
365
)
360
has
× .9650) + (100 × i × 182.5
× .9300)
(100 × i × 182.5
360
360
+ (100 × i × 182.5
× .8970) + (100 × i × 182.5
× .8650)
360
360
+ (100 × i × 182.5
× .8350) + (100 × i × 182.5
× .8050) = + 0.40
360
360
The solution to this is: i = + 0.15%
We can therefore add cashflows of + 3.5 now and –1.5 each year (NPV
= –0.40) if we also add 0.15% to LIBOR each six months (NPV =
+0.40). We can therefore achieve a par / par asset swap of LIBOR + 15
basis points.
326
Appendices
1 Using an HP calculator
2 A summary of market day/year conventions
3 A summary of calculation procedures
4 Glossary
5 ISO/SWIFT codes for currencies
327
APPENDIX 1
Using an HP calculator
INTRODUCTION
We have not tried to give full instructions here for using Hewlett Packard calculators, but have set out only those operations necessary for the examples
and exercises in this book.
The HP calculators generally used fall into three categories:
The HP12C calculator
It is essential first to understand the logic of this calculator, which is called
“reverse Polish notation” (RPN). On a traditional calculator, the steps are
entered in the same order as on a piece of paper. Thus, for example, the calculation 4 × 5 + 6 = 26 would be performed by entering 4, ×, 5, +, 6 and = in
that order. The result appears as 26.
With an HP12C using RPN, however, it is necessary instead to enter 4,
ENTER, 5, ×, 6 and +, in that order. The first number is generally followed
by ENTER; thereafter, each number is followed (rather than preceded as is
traditional) by its operator. In this example, we are multiplying by 5. The ×
therefore follows the 5 instead of the other way round.
The HP17BII and HP19BII
With these calculators, the user can choose whether to use RPN or the more
traditional algebraic logic, using the calculator’s MODES function. The
labels shown on the calculator’s keys for the various operation functions are
also different in a few cases from the HP12C.
The HP17B and HP19B
With these calculators, the user can use only the traditional “algebraic” logic.
In this Appendix, we show the essential steps for the HP12C and for the
HP19BII in each mode. This would be very cumbersome for all the examples
in the book, however, and we have therefore shown steps elsewhere in the
text for the HP19BII in RPN mode only. This will not give a problem to a
user of the HP12C and HP17BII in RPN, as the steps are the same even
though a few keys are labelled differently. The steps in algebraic mode are in
any case more familiar.
329
Mastering Financial Calculations
Basic operations
In the steps shown below, “f” and “g” refer to the yellow and blue shift keys
marked “f” and “g” on the HP12C and “■
■” refers to the yellow shift key on
the HP19BII. Also, the key “∧” may alternatively be marked “yx”.
Switching between algebraic and RPN modes
To switch the HP19BII to algebraic mode: ■ MODES MORE ALG
To switch the HP19BII to RPN mode: ■ MODES MORE RPN
Deleting an incorrect entry
To delete the current entry without affecting the calculation so far:
HP12C
HP19BII (RPN mode)
HP19BII (algebraic)
CLx
■ CLEAR
■ CLEAR
To delete the entire calculation so far:
HP12C
HP19BII (RPN mode)
HP19BII (algebraic)
f CLEAR REG
■ CLEAR DATA
■ CLEAR DATA
To correct the current entry before pressing another key:
HP12C
HP19BII (RPN mode)
not available
HP19BII (algebraic)
➡
➡
works as a backspace key
Number of decimal places
The number of decimal places displayed can be adjusted, without affecting
the accuracy of the calculation. For example, to display four decimal places:
HP12C
HP19BII (RPN mode)
HP19BII (algebraic)
f4
DISP FIX 4 INPUT
DISP FIX 4 INPUT
HP12C
HP19BII (RPN mode)
HP19BII (algebraic)
5 ENTER 4 +
5 ENTER 4 +
5+4=
Addition
Example: 5 + 4 = 9
330
Appendix 1 · Using an HP Calculator
Example: – 5 + 4 = –1
HP12C
HP19BII (RPN mode)
HP19BII (algebraic)
5 ENTER CHS 4 +
5 ENTER +/– 4 +
–5+4=
(Because the first entry in RPN must be a number rather
than an operator, it is necessary to enter the 5 and then
change its sign from positive to negative)
Subtraction
Example: 7 – 3 = 4
HP12C
HP19BII (RPN mode)
HP19BII (algebraic)
7 ENTER 3 –
7 ENTER 3 –
7–3=
HP12C
HP19BII (RPN mode)
HP19BII (algebraic)
8 ENTER 2 ÷ 5 ×
8 ENTER 2 ÷ 5 ×
8÷2×5=
HP12C
HP19BII (RPN mode)
HP19BII (algebraic)
3 ENTER 4 × 7 +
3 ENTER 4 × 7 +
3×4+7=
HP12C
HP19BII (RPN mode)
HP19BII (algebraic)
4 ENTER 7 × 3 +
4 ENTER 7 × 3 +
3 + (4 × 7) =
Multiplication, division
Example: 8 ÷ 2 × 5 = 20
Example: 3 × 4 + 7 = 19
Example: 3 + 4 × 7 = 31
Note that in the expression “3 + 4 × 7”, you must do the multiplication
before the addition. It is a convention of the way mathematical formulas are
written that any exponents (54, x2, 4.2®-q, etc.) must be done first, followed by
multiplication and division (0.08 × 92, x ÷ y, qu
_
´^ etc.) and addition and subtraction last. This rule is applied first to anything inside brackets (...) and
then to everything else.
331
Mastering Financial Calculations
Exponents
Example: 35 = 243
HP12C
HP19BII (RPN mode)
HP19BII (algebraic)
3 ENTER 5 yx
3 ENTER 5 ■ ∧
3■∧5=
Chaining
“Chaining” is performing a series of calculations in succession without the
need to keep stopping and starting or using memory stores.
Example:
[
(1 + 0.4 ×
(1 + 0.5 ×
78
)
360
28
)
360
]
–1 ×
360
50
= 0.3311
HP12C
HP19BII (RPN mode)
HP19BII (algebraic)
.4 ENTER 78 × 360 ÷
1+
.5 ENTER 28 × 360 ÷
1+
÷
1–
360 × 50 ÷
.4 ENTER 78 × 360 ÷
1+
.5 ENTER 28 × 360 ÷
1+
÷
1–
360 × 50 ÷
((1 + (.4 × 78 ÷ 360)) ÷
(1 + (.5 × 28 ÷ 360))
–1) × 360 ÷ 50 =
(Note that the ÷ in the fifth line divides the result of the
fourth line into the result of the second line without the
need to re-enter any interim results)
Reversing the order of the current operation
This can be useful in the middle of chaining.
Example:
332
85
=5
1+8×2
HP12C
HP19BII (RPN mode)
HP19BII (algebraic)
8 ENTER 2 × 1 +
85 xy ÷
8 ENTER 2 × 1 +
85 ■ xy ÷
Not available
(“xy” switches the order,
so that 85 is divided by the
result of “1 + 8 x 2”, instead
of the other way round)
(“■
■ xy” switches the order,
so that 85 is divided by the
result of “1 + 8 x 2”, instead
of the other way round)
Appendix 1 · Using an HP Calculator
Square roots
Example:
(9 + 7) [the same as (9 + 7) ] = 4
HP12C
9 ENTER 7 + g
x
HP19BII (RPN mode)
HP19BII (algebraic)
9 ENTER 7 + ■
9+7=■
x
x
Reciprocals
Example:
1
= 0.625
16
HP12C
HP19BII (RPN mode)
HP19BII (algebraic)
16 1/x
16 ■ 1/x
16 ■ 1/x
Example:
1
= 0.05
4×5
HP12C
4 ENTER 5 ×
1/x
HP19BII (RPN mode)
HP19BII (algebraic)
4 ENTER 5 × ■
4 x 5 = ■ 1/x
1/x
Example: (21 + 43) = 2
HP12C
21 ENTER 43 + 6
1/x
yx
HP19BII (RPN mode)
HP19BII (algebraic)
21 ENTER 43 +
6 ■ 1/x ■ ∧
21 + 43 = ■ ∧ 6 ■ 1/x =
Function menus
Various functions on the HP19BII are available through special menus and
sub-menus accessed by pressing the calculator’s top row of keys. Pressing
“EXIT” moves from the current level menu to the previous level. Pressing “■
MAIN” moves from the current level to the highest level menu.
Date calculations
The calculator can be switched to accept dates in either European format
(e.g. 18 August 1998 entered as 18.081998) or American format (e.g. 18
August 1998 entered as 08.181998). This switching is done as follows:
333
Mastering Financial Calculations
HP12C
HP19BII (RPN mode)
HP19BII (algebraic)
g D.MY
Select TIME menu
Select SET menu
Select M/D
Select TIME menu
Select SET menu
Select M/D
(This switches from the
existing format to the
other one)
(This switches from the
existing format to the
other one)
■ MAIN
■ MAIN
(for European format)
or
g M.DY
(for American format)
All our examples are shown using the European format.
Example: What is the number of true calendar days between 18 August 1998 and
12 December 1998?
Answer: 116
HP12C
HP19BII (RPN mode)
HP19BII (algebraic)
18.081998 ENTER
12.121998 g ∆DYS
Select TIME menu
Select CALC menu
18.081998 DATE1
12.121998 DATE2
DAYS
■ MAIN
Select TIME menu
Select CALC menu
18.081998 DATE1
12.121998 DATE2
DAYS
■ MAIN
Example: What is the number of days between 18 August 1998 and 12 December
1998 on a 30(A)/360 basis? (For an explanation of this, see the section “Day/year
conventions” in Chapter 5.)
Answer: 114
HP19BII (RPN mode)
HP19BII (algebraic)
Repeat the steps
above, followed by
xy or R
Repeat the steps
above, but type 360D
instead of DAYS
Repeat the steps
above, but type 360D
instead of DAYS
➡
HP12C
(Note that the HP calculators can perform date calculations based on the
American 30(A)/360 convention but not on the very similar European /
Eurobond 30(E)/360 convention.)
334
Appendix 1 · Using an HP Calculator
Example: What date is 180 calendar days after 18 August 1998?
Answer: 14 February 1999
HP12C
HP19BII (RPN mode)
HP19BII (algebraic)
18.081998 ENTER
180 g DATE
Select TIME menu
Select CALC menu
18.081998 DATE1
180 DAYS
DATE2
■ MAIN
Select TIME menu
Select CALC menu
18.081998 DATE1
180 DAYS
DATE2
■ MAIN
Other operations
Hewlett Packard calculators – particularly the HP17II and HP19II – have a
number of more sophisticated inbuilt functions on which the calculators’
manuals are the best source of information. Several of these functions are,
however, described elsewhere in this book in the appropriate chapters as they
become relevant. These are:
•
•
•
•
•
Time value of money: covered in Chapter 1.
Irregular cashflows: covered in Chapter 1.
Bond calculations: covered in Chapter 5.
Maths functions: examples of use are given in Chapter 1.
Solving equations: an example is given in Chapter 5.
335
APPENDIX 2
A Summary of Market Day/Year Conventions for
Money Markets and Government Bond Markets
Instrument
Day/year basis
Yield or
discount
Australia
Money market
Bond (semi-annual coupons)
ACT/365
ACT/ACT
Y
Austria
Money market
Bond (annual coupons)
ACT/360
30(E)/360
Y
Belgium
Money market
OLO (annual coupons)
ACT/365
30(E)/360
Y
Canada
Money market
Bond (semi-annual coupons)
Denmark
Money market
Bond (annual coupons)
Eire
Money market
Bond (annual and semi-annual
coupons)
Finland
Money market
Bond (annual coupons)
ACT/365
Y
ACT/365 (accrued coupon)
ACT/ACT (dirty price calculation)
ACT/360
30(E)/360
Y
ACT/365
30(E)/3601
Y
ACT/360
30(E)/360
Y
337
Mastering Financial Calculations
France
Money market
OAT, BTAN (annual coupons)
ACT/360
ACT/ACT
Y
Germany
Money market
Bund, OBL (annual coupons)
ACT/360
30(E)/360
Y
Italy
Money market
BTP (semi-annual coupons)
Japan
Money market
JGB (semi-annual coupons)
ACT/365
ACT3/365
Y
Netherlands
Money market
Bond (annual coupons)
ACT/360
30(E)/360
Y
Norway
T-bills
Other money market
Bond (annual coupons)
ACT/3654
ACT/360
ACT/365
Y
Y
Spain
Money market
Bono (annual coupons)
338
ACT/365
Y
2
30(E) /360 (accrued coupon)
ACT/365 (dirty price calculation)
ACT/360
Y
ACT/ACT (accrued coupon)
ACT/365 (dirty price calculation)
Sweden
T-bills
Other money market
Bond
30(E)/360
ACT/360
30(E)/360
Y
Y
Switzerland
Money market
Bond (annual coupons)
ACT/360
30(E)/360
Y
UK
Depo / CD / £CP / T-bill (ECU)
BA / T-bill (£)
Gilt (semi-annual coupons)
ACT/365
ACT/365
ACT/ACT5
Y
D
Appendix 2 · A Summary of Market Day/Year Conventions
USA
Depo / CD
BA / $CP / T-bill
T-bond / note
(semi-annual coupons)
Federal agency & corporate
bonds
30(A)/360
Euro (the single “domestic”
currency for certain European
Union countries from 1999)
Money market
Bond
ACT/360
ACT/ACT
Euromarket (non-domestic
markets generally)
Money market
Eurobond (annual coupons)
ACT/360
ACT/360
Y
D
ACT/ACT
Y
ACT/360 (exceptions using
Y
ACT/365 include GBP, IEP,
BEF / LUF, PTE, GRD, SGD,
HKD, MYR, TWD, THB, ZAR)
30(E)/360
Notes
1. Some older bonds still use ACT/365.
2. Accrued coupon calculation adds one day to the usual calculation (the start date
and end date are counted inclusively).
3. One day’s extra coupon is accrued in the first coupon period.
4. Quoted as an effective (annual equivalent) yield rather than a simple rate.
5. ACT/365 for accrued coupon until late 1998.
339
APPENDIX 3
A Summary of Calculation Procedures
Notation
The following general notation is used throughout these formulas, unless
something different is specifically mentioned:
D
FV
i
n
N
P
PV
r
R
year
zk
=
=
=
=
=
=
=
=
=
=
=
discount rate
future value, or future cashflow
interest rate or yield per annum
number of times per year an interest payment is made
number of years or number of coupon periods
price (dirty price for a bond)
present value, or cashflow now
continuously compounded interest rate
coupon rate paid on a security
number of days in the conventional year
zero-coupon yield for k years
Financial arithmetic basics
Effective and nominal rates
If the interest rate with n payments per year is i, the effective rate (equivalent
annual rate) i* is:
n
[( ) ]
i* = 1 + ni – 1
Similarly:
[
]
1
i = (1 + i*)n × n
(
Effective rate = 1 + i ×
days
year
)
365
days
–1
Effective rate on a 360-day basis = effective rate ×
360
365
341
Mastering Financial Calculations
Continuously compounded interest rate
r=
(
365
× LN 1 + i × days
year
days
)
days
Discount factor = er× 365
where i is the nominal rate for that number of days
In particular, when i is the effective rate:
r = LN(1 + i)
and:
i=
(
)
days
year
× er× 365 – 1
days
Short-term investments
(
FV = PV × 1 + i ×
PV =
days
year
)
FV
(1 + i × days
)
year
year
– 1) ×
( FV
PV
days
FV
Effective yield = (
PV )
i=
365
days
–1
1
1 + i × days
year
Discount factor =
Long-term investments over N years
FV = PV × (1 + i)N
PV =
i=
FV
(1 + i)N
( FV
PV )
1
N
–1
Discount factor =
( 1 1+ i )
N
NPV and internal rate of return
NPV = sum of all the present values
The internal rate of return is the interest rate which discounts all the future
cashflows to a given NPV. This is equivalent to the interest rate which discounts all the cashflows including any cashflow now to zero.
342
Appendix 3 · A Summary of Calculation Procedures
Interpolation and extrapolation
i = i1 + (i2 – i1) ×
where:
(d – d1)
(d2 – d1)
i is the rate required for d days
i1 is the known rate for d1 days
i2 is the known rate for d2 days
The money market
Interest rate on 360-day basis = interest rate on 365-day basis ×
360
365
Interest rate on 365-day basis = interest rate on 360-day basis ×
365
360
Certificate of deposit
Maturity proceeds = face value ×
to maturity
(1 + coupon rate × days from issue
)
year
maturity proceeds
Secondary market proceeds =
(1 + market yield ×
days left to maturity
year
)
Return on holding a CD =
[
to maturity
(1 + purchase yield × days from purchase
)
year
(1 + sale yield ×
days from sale to maturity
year
)
]
–1 ×
year
days held
Discount instrument
Maturity proceeds = face value
Secondary market proceeds =
face value
(1 + market yield ×
days left to maturity
year
)
343
Mastering Financial Calculations
Instruments quoted on a discount rate
Rate of true yield =
Discount rate =
discount rate
)
(1 – discount rate × days
year
rate of true yield
(1 + yield × days
)
year
Amount of discount = face value × discount rate ×
Amount paid = face value × (1 – discount rate ×
days
year
days
)
year
Instruments quoted on a discount rate:
US: T-bill
UK: T-bill (£)
BA
BA
CP
Medium-term CD
P=F×
R
d
× Σ[
[ A1 + ( year
A ])]
N
= (1 + i ×
where: Ak
k–1;k
k=1
N
k
dp1
d
d
) × (1 + i × 12 ) × (1 + i × 23 )
year
year
year
...× (1 + i ×
dk–1;k
)
year
N
= number of coupons not yet paid
dk–1;k = number of days between (k–1)th coupon and kth
coupon
dp1
= number of days between purchase and first
coupon
Forward-forwards and forward rate agreements
For periods up to one year:
Forward-forward rate =
where:
344
iL
iS
dL
dS
=
=
=
=
[
d
(1 + i × year
) – 1 × year
(d – d )
d
(1 + i × year )
L
L
S
S
]
interest rate for longer period
interest rate for shorter period
number of days in longer period
number of days in shorter period
L
S
Appendix 3 · A Summary of Calculation Procedures
FRA settlement amount = principal ×
where:
(f – L) × days
year
(1 + L × days
)
year
f
= FRA rate
L
= LIBOR at the beginning of the FRA period
days = number of days in the FRA period
For periods longer than a year but less than 2 years:
FRA settlement = principal ×
where:
(f – L) ×
(1 + L ×
d1
year
d1
year)
+
(f – L) ×
(1 + L ×
d1
year)
d2
year
× (1 + L ×
d2
year)
d1 = number of days in the first year of the FRA period
d2 = number of days from d1 until the end of the FRA period
Constructing a strip
The
interest
rate
forfor
a longer
period
upup
to to
oneone
year
= =
The
interest
rate
a longer
period
year
[(
1 + i1 ×
where:
) (
d1
d2
× 1 + i2 ×
year
year
)
× (1 + i3 ×
)
]
d3
year
× ... – 1 ×
year
total days
i1, i2, i3, ... are the cash interest rate and forward-forward rates for a
series of consecutive periods lasting d1, d2, d3, ... days.
Interest rate futures
Price = 100 – (implied forward-forward interest rate × 100)
Profit / loss on long position in a 3 month contract =
notional contract size ×
(sale price – purchase price) 1
×
100
4
Basis
= implied cash price – actual futures price
Theoretical basis = implied cash price – theoretical futures price
Value basis
= theoretical futures price – actual futures price
Bond market calculations
General dirty price formula
P = NPV of all future cashflows = Σk
where:
Ck
( )
1 + ni
dk × n
year
Ck = the kth cashflow arising
dk = number of days until Ck
i = yield on the basis of n interest payments per year
345
Mastering Financial Calculations
Conventional dirty price formula
P=
100
(1 + ni )W
where:
[
1
1–
(
(1
+
) )
R
1
×
+
n
1
(1 – (1 + ) ) (1 + )
i N
n
i
n
i N–1
n
]
R = the annual coupon rate paid n times per year
W = the fraction of a coupon period between purchase and
the next coupon to be received
N = the number of coupon payments not yet made
i = yield per annum based on n payments per year
Accrued coupon = 100 × coupon rate ×
days since last coupon
year
For ex-dividend prices, accrued coupon is negative:
Accrued coupon = – 100 × coupon rate ×
days to next coupon
year
Clean price = dirty price – accrued coupon
Price falls as yield rises and vice versa.
Generally, if a bond’s price is greater than par, its yield is less than the
coupon rate and vice versa – except that, on a non-coupon date, if a bond is
priced at par, the yield is slightly lower than the coupon rate.
Other yields
Current yield =
coupon rate
clean price
100
/
coupon rate +
Simple yield to maturity =
(
redemption amount – clean price
years to maturity
)
clean price
/100
Alternative yield in final coupon period (simple)
i=
including coupon
year
– 1] ×
[ total final cashflow
dirty price
days to maturity
where days and year are measured on the relevant bond basis
Bond equivalent yield for US T-bill
If 182 days or less to maturity:
i=
346
D
365
×
1 – D × days
360
360
Appendix 3 · A Summary of Calculation Procedures
If more than 182 days to maturity:
(
– days
+ (days
)2 + 2 × ((days
– 12) ×
365
365
365
i=
( (1 – D1×
days
)
360
))
–1
1
2
(days
– 12)
365
If 29 February falls in the 12-month period starting on the purchase date,
replace 365 by 366.
Money market yield
(1 – (1 + 1× ) )
+
1
1
–
( (1 + × ) ) (1 +
[
i
n
100
R
P=
×
i
(1 + n × W) n
365 N
360
i
n
365
360
i
n
1
N–1
× 365
360)
]
where i and W are the yield and fraction of a coupon period on a money
market basis rather than a bond basis.
Moosmüller yield
1
1–
(1 + ni )N
100
R
1
P=
×
+
i
n
1
(1 + n × W)
(1 + ni )N–1
1–
i
(1 + n)
[
(
)
)
(
]
where i and W are the yield and fraction of a coupon period on a bond basis.
Duration and convexity
(Macaulay) duration =
Modified duration = –
Σ (present value of cashflow × time to cashflow)
Σ (present value of cashflow)
dP
di
/ dirty price =
duration
(1 + i/n)
DV01 = modified duration × dirty price × 0.0001
Approximation
Change in price ≈ – dirty price × change in yield × modified duration
Convexity =
–
d2P
di2
Ck
/ dirty price = Σ [ (1 + / )
k
i
n
dk
n year
+2
×
dk
dk
1
+
year year n
(
)] dirty price
where dk is the number of days to cashflow Ck
347
Mastering Financial Calculations
Better approximation
Change in price ≈ – dirty price × modified duration × change in yield
+ 12 dirty price × convexity × (change in yield)2
Approximations for a portfolio
Duration =
Σ(duration of investment × value of each investment)
value of porfolio
Modified duration =
Convexity =
Σ(mod. dur. of each investment × value of each investment)
value of porfolio
Σ(convexity of each investment × value of each investment)
value of portfolio
Bond futures
Conversion factor =
clean price at delivery for one unit of the deliverable
bond, at which that bond’s yield equals the futures
contract notional coupon rate
Theoretical bond futures price =
([bond price + accrued coupon now] × [1 + i × ]) –
days
year
(accrued coupon at delivery) – (intervening coupon reinvested)
conversion factor
where i = short-term funding rate
Forward bond price =
([bond price + accrued coupon now] × [1 + i × ]) –
days
year
(accrued coupon at delivery) – (intervening coupon reinvested)
where i = short-term funding rate
Generally, a forward bond price is at a premium (discount) to the cash price
coupon rate .
if the short-term funding cost is greater than (less than) cash price
/100
348
Appendix 3 · A Summary of Calculation Procedures
Hedge ratio
notional amount of futures contract required to hedge a position in bond A
=
face value of bond A
dirty price of bond A
modified duration of bond A
×
×
dirty price of CTD bond
modified duration of CTD bond
conversion factor for CTD bond
delivery
)
(1 + i × days to futures
year
where i = short-term funding rate
Cashflows in a classic repo
Cash paid at the beginning =
nominal bond amount × (clean price + accrued coupon)
100
Cash repaid at the end =
days
cash consideration at the beginning × 1 + repo rate ×
year
Implied repo rate =
(
[
)
(futures price × conversion factor) +
year
(accrued coupon at delivery of futures) +
×
(interim coupon reinvested)
days
–1
(bond price + accrued coupon now)
]
Cash-and-carry arbitrage
Assume the arbitrage is achieved by buying the cash bond and selling
the futures:
Cash cost at start = nominal bond amount
× (cash bond price + accrued coupon at start)/100
Total payments = (cash cost at start) ×
delivery
(1 + repo rate × days to futures
)
year
Total receipts = nominal bond amount × (futures price × conversion factor +
accrued coupon at delivery of futures)
100
Profit = total receipts – total payments
For each futures, the bond amount above is
notional contract size
conversion factor
Basis = bond price – futures price × conversion factor
Net cost of carry = coupon income – financing cost
Net basis = basis – net cost of carry
349
Mastering Financial Calculations
Zero-coupon rates and yield curves
Par yield for N years =
1 – dfN
N
Σ dfk
k=1
where dfk = zero-coupon discount factor for k years
Forward-forward zero-coupon yield from k years to m years =
[
(1 + zm)m
(1 + zk)k
]
1
(m–k)
–1
In particular:
Forward-forward yield from k years to (k + 1) years =
(1 + zk+1)k+1
–1
(1 + zk)k
Creating a strip
1
zk = [(1 + i1) × (1 + i2) × (1 + i3) × ... × (1 + ik)] k – 1
where i1, i2, i3 ... ik are the 1-year cash interest rate and the 1-year v 2-year,
2-year v 3-year, ... , (k -1)-year v k-year forward-forward rates
Conversion between yield curves
To create a zero-coupon yield from coupon-bearing yields: bootstrap
To calculate the yield to maturity on a non-par coupon-bearing bond from
zero-coupon yields: calculate the NPV of the bond using the zero-coupon
yields, then calculate the yield to maturity of the bond from this dirty price
To create a par yield from zero-coupon yields: use the formula above
To create a forward-forward yield from zero-coupon yields: use the formula
above
To create a zero-coupon yield from forward-forward yields: create a strip of
the first cash leg with a series of forward-forwards
Foreign exchange
To calculate cross-rates from dollar rates
Between two indirect rates or two direct rates against the dollar: divide opposite sides of the dollar exchange rates.
Between one indirect rate and one direct rate against the dollar: multiply the
same sides of the dollar exchange rates.
350
Appendix 3 · A Summary of Calculation Procedures
In general:
Given two exchange rates A/B and A/C, the cross-rates are:
B/C = A/C ÷ A/B
C/B = A/B ÷ A/C
Given two exchange rates B/A and A/C, the cross-rates are:
B/C = B/A × A/C
C/B = 1 ÷ (B/A × A/C)
When dividing, use opposite sides. When multiplying, use the same sides.
Forwards
Forward outright = spot ×
(1 + variable currency interest × days
)
year
(1 + base currency interest rate × days
)
year
Forward swap = spot ×
days
days
(variable currency interest rate × year
– base currency interest rate × year
)
days
(1 + base currency interest rate × year
)
Forward outright = spot + forward swap
Approximations
Forward swap ≈ spot × interest rate differential ×
Interest rate differential ≈
days
year
forward swap year
×
spot
days
Premiums and discounts
1. The currency with higher interest rates ( = the currency at a “discount”) is
worth less in the future.
The currency with lower interest rates ( = the currency at a “premium”) is
worth more in the future.
2. The bank quoting the price buys the base currency / sells the variable
currency on the far date on the left.
The bank quoting the price sells the base currency / buys the variable
currency on the far date on the right.
3. For outrights later than spot, if the swap price is larger on the right than
the left, add it to the spot price. If the swap price is larger on the left than
the right, subtract it from the spot price.
4. For outrights later than spot, the right-hand swap price is added to (or
subtracted from) the right-hand spot price; the left-hand swap price is
added to (or subtracted from) the left-hand spot price.
351
Mastering Financial Calculations
5. For outright deals earlier than spot, calculate as if the swap price is
reversed and follow (3) and (4).
6. Of the two prices available, the customer gets the worse one. Thus if the
swap price is 3 / 2 and the customer knows that the points are “in his/her
favour” (the outright will be better than the spot), the price will be 2. If
he/she knows that the points are “against him/her” (the outright will be
worse than the spot), the price will be 3.
7. The effect of combining the swap points with the spot price will always be
to widen the spread, never to narrow it.
A forward dealer expecting the interest rate differential to move in favour of
the base currency (for example, base currency interest rates rise or variable
currency interest rates fall) will “buy and sell” the base currency. This is
equivalent to borrowing the base currency and depositing in the variable currency. And vice versa.
Covered interest arbitrage
Variable currency rate created =
[(
1 + base currency rate ×
days
base year
)
×
]
outright
variable year
–1 ×
spot
days
Base currency rate created =
[(
1 + variable currency rate ×
)
]
days
spot
base year
×
–1 ×
variable year
outright
days
Forward-forward price after spot
Left side = (left side of far-date swap) – (right side of near-date swap)
Right side = (right side of far-date swap) – (left side of near-date swap)
Time option
A time option price is the best for the bank / worst for the customer over the
time option period.
Long-dated forwards
Forward outright = spot ×
(1 + variable interest rate)N
(1 + base interest rate)N
SAFEs
FXA settlement amount =
= A2 ×
352
[
(OER – SSR( + (CFS – SFS)
(1 + L × days
)
year
]
– A1 × [OER – SSR]
Appendix 3 · A Summary of Calculation Procedures
paid by the “seller” to the “buyer” of the FXA (or vice versa if it is a negative amount), where the “buyer” is the party which buys the base currency
on the first date and sells it on the second date.
where:
A1
= the base currency amount transacted at the beginning of
the swap
A2 = the base currency amount transacted at the end of the swap
OER = the outright exchange rate, when the FXA is transacted, to
the beginning of the swap period
SSR = the settlement spot rate two working days before the
swap period
CFS = the contract forward spread – that is, the swap price agreed
when the FXA is transacted
SFS = the settlement forward spread – that is, the swap price used
for settlement two working days before the swap period
L
= variable currency LIBOR for the swap period, two working
days before the swap period
days = the number of days in the swap period
year = the year basis for the variable currency
ERA settlement amount = A ×
( 1CFS+ L–×SFS )
days
year
Buy FRA in currency A = buy FRA in currency B + buy FXA in rate A/B
Buy FRA in currency A + sell FRA in currency B + sell FXA in rate A/B = 0
Covered interest arbitrage (forward)
Variable currency FRA rate =
[(
)
1 + base currency FRA × days
×
year
]
outright to far date
variable year
–1 ×
outright to near date
days
Base currency FRA rate =
[(
)
days
1 + variable currency FRA × variable
×
year
]
outright to near date
base year
–1 ×
outright to far date
days
Forward-forward swap =
outright to near date ×
(variable currency FRA × days
– base currency FRA × days
)
year
year
(1 + base currency FRA × days
)
year
353
Mastering Financial Calculations
Interest rate swaps and currency swaps
Pricing interest rate swaps from futures or FRAs
• For each successive futures maturity, create a strip to generate a discount factor
• Use the series of discount factors to calculate the yield of a par swap
Valuing swaps
To value a swap, calculate the NPV of the cashflows, preferably using zerocoupon swap yields or the equivalent discount factors.
To value floating-rate cashflows, superimpose offsetting floating-rate cashflows known to have an NPV of zero – effectively an FRN.
To value cashflows in a different currency, convert the resulting NPV at the
spot exchange rate.
A swap at current rates has an NPV of zero.
If a current swap involves an off-market fixed rate, this is compensated by a
one-off payment or by an adjustment to the other side of the swap, so as to
maintain the NPV at zero.
The current swap rate for a swap based on an irregular or forward-start
notional principal is again the rate which gives the swap an NPV of zero.
Options
Price quotation
Currency option price expressed as points of the variable currency =
(price expressed as percentage of the base currency amount) × spot exchange rate.
Currency option price expressed as percentage of base currency amount =
(price expressed as points of the variable currency) ÷ spot exchange rate.
Basic statistics
Mean (µ) = sum of all the values divided by the number of values.
Variance (σ2) = mean of (difference from mean)2
When estimating the variance from only a sample of the data rather than all
the data, divide by one less than the number of values used.
Standard deviation (σ) =
variance
Historic volatility
Historic volatility = standard deviation of LN(relative price movement) ×
frequency of data per year
Take a series of n price data.
354
Appendix 3 · A Summary of Calculation Procedures
Divide each price by the previous day’s price to give the relative price change
– so that you now have only (n–1) data.
Take the natural logarithms (LN) of these (n–1) relative price changes. These
are now the data from which to calculate the annualised standard deviation
(= volatility). This is calculated as above:
•
•
•
•
•
Calculate the mean
Calculate the differences from the mean
Square the differences
Add these squares and divide by (n–2)
Calculate the square root
To annualize volatility, multiply by the square root of the frequency of data
per year.
Black–Scholes
Option-pricing formula for a non-dividend-paying asset:
Call premium = spot price × N(–d1) – strike price × N(d2) × e–rt
Put premium = – spot price × N(–d1) + strike price × N(–d2) × e–rt
= call premium + strike price × e–rt – spot price
(
LN
where:
d1 =
)+
σ2t
2
)–
σ2t
2
σ t
(
LN
d2 =
t
=
σ
=
r
=
N(d) =
spot × ert
strike
spot × ert
strike
σ t
the time to expiry of the option as a proportion of a year
the annualized volatility
the continuously compounded interest rate
the standardized normal cumulative probability distribution
The normal distribution function can be approximated by:
0.4361836
N(d) = 1 –
1+0.33267d
N(d) = 1 – N(–d)
–
0.1201676
(1+0.33267d)2
d2
2π e 2
+
0.937298
(1+0.33267d)3
when d ≥ 0 and
when d < 0
355
Mastering Financial Calculations
Currency option pricing formula:
Call premium = (forward price × N(d1) – strike price × N(d2)) × e–rt
Put premium = (– forward price × N(–d1) + strike price × N(–d2)) × e–rt
= call premium + (strike price – forward price) × e–rt
where: the option is a call on a unit of the base currency (that is, a put on the variable currency) and the premium is expressed in units of the variable
currency.
(
LN
d1 =
forward
strike
)+
σ2t
2
)–
σ2t
2
σ t
(
LN
d2 =
forward
strike
σ t
r = the continuously compounded interest rate for the variable
currency
Put–call relationship
Call premium = put premium + spot – strike × e–rt
= put premium + (forward – strike) × e–rt
Put premium = call premium – spot – strike × e–rt
= call premium – (forward – strike) × e–rt
where:
r = continuously compounded interest rate
t = time to expiry as a proportion of a year
In particular, when the strike is the same as the simple forward, the call and
put premiums are equal (put – call parity).
The expressions ert and e–rt in the various formulas above can be replaced by (1
+ i × t) and (1+i1 × t) respectively, where i is the simple interest rate for the
period.
Synthetic forwards:
Buy forward = buy call plus sell put
Sell forward = sell call plus buy put
Risk reversal
Buy call
Sell call
Buy put
Sell put
356
= buy put plus buy forward
= sell put plus sell forward
= buy call plus sell forward
= sell call plus buy forward
Appendix 3 · A Summary of Calculation Procedures
Option price sensitivities
delta (∆) =
change in option’s value
change in underlying’s value
gamma (Γ) =
vega =
change in delta
change in underlying’s value
change in option’s value
change in volatility
theta (θ) = –
change in option’s value
change in time
change in option’s value
change in interest rate
rho (ρ) =
based on the Black–Scholes formula:
∆ = N(d1) for a call
or –N(–d1) for a put
1
Γ=
2
d1
for a call or a put
Sσ 2πt e 2
vega =
t
2π
S
d12
2
for a call or a put
e
2
Sσ e– d21 – Kre–rtN(d ) for a call
2
2 2πt
2
d1
or – Sσ e– 2 + Kre–rtN(–d2) for a put
2 2πt
theta (Θ) =
rho (ρ) = Kte–rtN(d2) for a call
or –Kte–rtN(–d2) for a put
where: S = spot price for the asset
K = strike price
357
APPENDIX 4
Glossary
30/360
(Or 360/360). A day/year count convention assuming
30 days in each calendar month and a “year” of 360
days; adjusted in America for certain periods ending on
31st day of the month.
360/360
Same as 30/360.
Accreting
An accreting principal is one which increases during the
life of the deal. See amortizing, bullet.
Accrued interest
The proportion of interest or coupon earned on an investment from the previous coupon payment date until the
value date.
Accumulated value
Same as future value.
ACT/360
A day/year count convention taking the number of calendar days in a period and a “year” of 360 days.
ACT/365
(Or ACT/365 fixed). A day/year count convention taking
the number of calendar days in a period and a “year” of
365 days. Under the ISDA definitions used for interest
rate swap documentation, ACT/365 means the same as
ACT/ACT.
ACT/365 fixed
See ACT/365.
ACT/ACT
A day/year count convention taking the number of calendar days in a period and a “year” equal to the number of
days in the current coupon period multiplied by the
coupon frequency. For an interest rate swap, that part of
the interest period falling in a leap year is divided by 366
and the remainder is divided by 365.
American
An American option is one which may be exercised at
any time during its life. See European.
Amortizing
An amortizing principal is one which decreases during
the life of the deal, or is repaid in stages during a loan.
Amortizing an amount over a period of time also
means accruing for it pro rata over the period. See
accreting, bullet.
Annuity
An investment providing a series of (generally equal)
future cashflows.
359
Mastering Financial Calculations
360
Appreciation
An increase in the market value of a currency in terms of
other currencies. See depreciation, revaluation.
Arbitrage
Arbitrage is the simultaneous operation in two different
but related markets in order to take advantage of a discrepancy between them which will lock in a profit. The
arbitrage operation itself usually tends to cause the different markets to converge. See covered interest arbitrage.
Asian
An Asian option depends on the average value of the
underlying over the option’s life.
Ask
See offer.
Asset-backed security
A security which is collateralized by specific assets – such
as mortgages – rather than by the intangible creditworthiness of the issuer.
Asset swap
An interest rate swap or currency swap used in conjunction with an underlying asset such as a bond investment.
See liability swap.
At-the-money
(Or ATM). An option is at-the-money if the current value
of the underlying is the same as the strike price. See inthe-money, out-of-the-money.
ATM
See at-the-money.
Backwardation
The situation when a forward or futures price for something is lower than the spot price (the same as forward
discount in foreign exchange). See contango.
Band
The Exchange Rate Mechanism (ERM) of the European
Monetary System (EMS) links the currencies of Austria,
Belgium, Denmark, Finland, France, Germany, Ireland,
Italy, Luxembourg, Netherlands, Portugal and Spain in a
system which limits the degree of fluctuation of each currency against the others within a band of 15 percent
either side of an agreed par value.
Banker’s acceptance
See bill of exchange.
Barrier option
A barrier option is one which ceases to exist, or starts to
exist, if the underlying reaches a certain barrier level. See
knock out / in.
Base currency
Exchange rates are quoted in terms of the number of
units of one currency (the variable or counter currency)
which corresponds to one unit of the other currency (the
base currency).
Basis
The underlying cash market price minus the futures price.
In the case of a bond futures contract, the futures price
must be multiplied by the conversion factor for the cash
bond in question.
Appendix 4 · Glossary
Basis points
In interest rate quotations, 0.01 percent.
Basis risk
The risk that the prices of two instruments will not move
exactly in line – for example, the price of a particular
bond and the price of a futures contract being used to
hedge a position in that bond.
Basis swap
An interest rate swap where both legs are based on floating rate payments.
Basis trade
Buying the basis means selling a futures contract and
buying the commodity or instrument underlying the
futures contract. Selling the basis is the opposite.
Bear spread
A spread position taken with the expectation of a fall in
value in the underlying.
Bearer security
A security where the issuer pays coupons and principal to
the holders of the security from time to time, without the
need for the holders to register their ownership; this provides anonymity to investors.
Bid
In general, the price at which the dealer quoting a price is
prepared to buy or borrow. The bid price of a foreign
exchange quotation is the rate at which the dealer will
buy the base currency and sell the variable currency. The
bid rate in a deposit quotation is the interest rate at
which the dealer will borrow the currency involved. The
bid rate in a repo is the interest rate at which the dealer
will borrow the collateral and lend the cash. See offer.
Big figure
In a foreign exchange quotation, the exchange rate omitting the last two decimal places. For example, when
USD/DEM is 1.5510 / 20, the big figure is 1.55. See points.
Bill of exchange
A short-term, zero-coupon debt issued by a company to
finance commercial trading. If it is guaranteed by a bank,
it becomes a banker’s acceptance.
Binomial tree
A mathematical model to value options, based on the
assumption that the value of the underlying can move
either up or down a given extent over a given short time.
This process is repeated many times to give a large
number of possible paths (the “tree”) which the value
could follow during the option’s life.
Black–Scholes
A widely used option pricing formula devised by Fischer
Black and Myron Scholes.
Bond basis
An interest rate is quoted on a bond basis if it is on an
ACT/365, ACT/ACT or 30/360 basis. In the short term
(for accrued interest, for example), these three are different. Over a whole (non-leap) year, however, they all
361
Mastering Financial Calculations
equate to 1. In general, the expression “bond basis” does
not distinguish between them and is calculated as
ACT/365. See money-market basis.
362
Bond-equivalent yield
The yield which would be quoted on a US treasury bond
which is trading at par and which has the same economic
return and maturity as a given treasury bill.
Bootstrapping
Building up successive zero-coupon yields from a combination of coupon-bearing yields.
Bräss/Fangmeyer
A method for calculating the yield of a bond similar to
the Moosmüller method but, in the case of bonds which
pay coupons more frequently than annually, using a mixture of annual and less than annual compounding.
Break forward
A product equivalent to a straightforward option, but
structured as a forward deal at an off-market rate which
can be reversed at a penalty rate.
Broken date
(Or odd date). A maturity date other than the standard
ones (such as 1 week, 1, 2, 3, 6 and 12 months) normally
quoted.
Bull spread
A spread position taken with the expectation of a rise in
value in the underlying.
Bullet
A loan / deposit has a bullet maturity if the principal is all
repaid at maturity. See amortizing.
Buy / sell-back
Opposite of sell / buy-back.
Cable
The exchange rate for sterling against the US dollar.
Calendar spread
The simultaneous purchase / sale of a futures contract for
one date and the sale / purchase of a similar futures contract for a different date. See spread.
Call option
An option to purchase the commodity or instrument
underlying the option. See put.
Cap
A series of borrower’s IRGs, designed to protect a borrower
against rising interest rates on each of a series of dates.
Capital market
Long-term market (generally longer than one year) for
financial instruments. See money market.
Cash
See cash market.
Cash-and-carry
A round trip (arbitrage) where a dealer buys bonds, repos
them out for cash to fund their purchase, sells bond
futures and delivers the bonds to the futures buyer at
maturity of the futures contract.
Cash market
The market for trading an underlying financial instrument, where the whole value of the instrument will
Appendix 4 · Glossary
potentially be settled on the normal delivery date – as
opposed to contracts for differences, futures, options, etc.
(where the cash amount to be settled is not intended to be
the full value of the underlying) or forwards (where delivery is for a later date than normal). See derivative.
CD
See certificate of deposit.
Ceiling
Same as cap.
Certificate of deposit
(Or CD). A security, generally coupon-bearing, issued by
a bank to borrow money.
Cheapest to deliver
(Or CTD). In a bond futures contract, the one underlying
bond among all those that are deliverable, which is the
most price-efficient for the seller to deliver.
Classic repo
(Or repo or US-style repo). Repo is short for “sale and
repurchase agreement” – a simultaneous spot sale and
forward purchase of a security, equivalent to borrowing
money against a loan of collateral. A reverse repo is the
opposite. The terminology is usually applied from the
perspective of the repo dealer. For example, when a central bank does repos, it is lending cash (the repo dealer is
borrowing cash from the central bank).
Clean deposit
Same as time deposit.
Clean price
The price of a bond excluding accrued coupon. The price
quoted in the market for a bond is generally a clean price
rather than a dirty price.
Collar
The simultaneous sale of a put (or call) option and purchase of a call (or put) at different strikes – typically both
out-of-the-money.
Collateral
(Or security). Something of value, often of good creditworthiness such as a government bond, given temporarily
to a counterparty to enhance a party’s creditworthiness.
In a repo, the collateral is actually sold temporarily by
one party to the other rather than merely lodged with it.
Commercial paper
A short-term security issued by a company or bank, generally with a zero coupon.
Compound interest
When some interest on an investment is paid before
maturity and the investor can reinvest it to earn interest
on interest, the interest is said to be compounded.
Compounding generally assumes that the reinvestment
rate is the same as the original rate. See simple interest.
Contango
The situation when a forward or futures price for something is higher than the spot price (the same as forward
premium in foreign exchange). See backwardation.
363
Mastering Financial Calculations
Continuous
compounding
A mathematical, rather than practical, concept of
compound interest where the period of compounding is
infinitesimally small.
Contract date
The date on which a transaction is negotiated. See value
date.
Contract for differences A deal such as an FRA and some futures contracts, where
the instrument or commodity effectively bought or sold
cannot be delivered; instead, a cash gain or loss is taken
by comparing the price dealt with the market price, or an
index, at maturity.
Conversion factor
(or price factor). In a bond futures contract, a factor to
make each deliverable bond comparable with the
contract’s notional bond specification. Defined as the
price of one unit of the deliverable bond required to make
its yield equal the notional coupon. The price paid for a
bond on delivery is the futures settlement price times the
conversion factor.
Convertible currency
A currency that may be freely exchanged for other currencies.
Convexity
A measure of the curvature of a bond’s price / yield curve
2P
di2
(mathematically, d
364
dirty price).
Corridor
Same as collar.
Cost of carry
The net running cost of holding a position (which may be
negative) – for example, the cost of borrowing cash to
buy a bond less the coupon earned on the bond while
holding it.
Counter currency
See variable currency.
Coupon
The interest payment(s) made by the issuer of a security
to the holders, based on the coupon rate and face value.
Coupon swap
An interest rate swap in which one leg is fixed-rate and
the other floating-rate. See basis swap.
Cover
To cover an exposure is to deal in such a way as to
remove the risk – either reversing the position, or hedging
it by dealing in an instrument with a similar but opposite
risk profile.
Covered call / put
The sale of a covered call option is when the option
writer also owns the underlying. If the underlying rises in
value so that the option is exercised, the writer is protected by his position in the underlying. Covered puts are
defined analogously. See naked.
Appendix 4 · Glossary
Covered interest
arbitrage
Creating a loan / deposit in one currency by combining a loan
/ deposit in another with a forward foreign exchange swap.
CP
See commercial paper.
Cross
See cross-rate.
Cross-rate
Generally an exchange rate between two currencies, neither of which is the US dollar. In the American market,
spot cross is the exchange rate for US dollars against
Canadian dollars in its direct form.
CTD
See cheapest to deliver.
Cum-dividend
When (as is usual) the next coupon or other payment due on
a security is paid to the buyer of a security. See ex-dividend.
Currency swap
An agreement to exchange a series of cashflows determined in one currency, possibly with reference to a
particular fixed or floating interest payment schedule, for
a series of cashflows based in a different currency. See
interest rate swap.
Current yield
Bond coupon as a proportion of clean price per 100; does
not take principal gain / loss or time value of money into
account. See yield to maturity, simple yield to maturity.
Cylinder
Same as collar.
DAC – RAP
Delivery against collateral – receipt against payment.
Same as DVP.
Deliverable bond
One of the bonds which is eligible to be delivered by the
seller of a bond futures contract at the contract’s maturity,
according to the specifications of that particular contract.
Delta (∆)
The change in an option’s value relative to a change in
the underlying’s value.
Depreciation
A decrease in the market value of a currency in terms of
other currencies. See appreciation, devaluation.
Derivative
Strictly, any financial instrument whose value is derived
from another, such as a forward foreign exchange rate, a
futures contract, an option, an interest rate swap, etc.
Forward deals to be settled in full are not always called
derivatives, however.
Devaluation
An official one-off decrease in the value of a currency in
terms of other currencies. See revaluation, depreciation.
Direct
An exchange rate quotation against the US dollar in
which the dollar is the variable currency and the other
currency is the base currency.
Dirty price
The price of a security including accrued coupon. See
clean price.
365
Mastering Financial Calculations
Discount
The amount by which a currency is cheaper, in terms of
another currency, for future delivery than for spot, is the
forward discount (in general, a reflection of interest rate
differentials between two currencies). If an exchange rate
is “at a discount” (without specifying to which of the two
currencies this refers), this generally means that the variable currency is at a discount. See premium.
To discount a future cashflow means to calculate its present value.
366
Discount rate
The method of market quotation for certain securities
(US and UK treasury bills, for example), expressing the
return on the security as a proportion of the face value of
the security received at maturity – as opposed to a yield
which expresses the return as a proportion of the original
investment.
Duration
(Or Macaulay duration). A measure of the weighted
average life of a bond or other series of cashflows, using
the present values of the cashflows as the weights. See
modified duration.
DVP
Delivery versus payment, in which the settlement mechanics of a sale or loan of securities against cash is such that
the securities and cash are exchanged against each other
simultaneously through the same clearing mechanism and
neither can be transferred unless the other is.
Effective rate
An effective interest rate is the rate which, earned as
simple interest over one year, gives the same return as
interest paid more frequently than once per year and then
compounded. See nominal rate.
End-end
A money market deal commencing on the last working
day of a month and lasting for a whole number of
months, maturing on the last working day of the corresponding month.
Epsilon (ε)
Same as vega.
Equivalent life
The weighted average life of the principal of a bond
where there are partial redemptions, using the present
values of the partial redemptions as the weights.
ERA
See exchange rate agreement.
Eta (η)
Same as vega.
Euro
The name for the proposed currency of the European
Monetary Union.
Eurocurrency
A Eurocurrency is a currency owned by a non-resident of
the country in which the currency is legal tender.
Appendix 4 · Glossary
Euromarket
The international market in which Eurocurrencies
are traded.
European
A European option is one that may be exercised only at
expiry. See American.
Exchange controls
Regulations restricting the free convertibility of a currency into other currencies.
Exchange rate
agreement
(Or ERA). A contract for differences based on the
movement in a forward-forward foreign exchange swap
price. Does not take account of the effect of spot rate
changes as an FXA does. See SAFE.
Exchange-traded
Futures contracts are traded on a futures exchange, as
opposed to forward deals which are OTC. Some option
contracts are similarly exchange traded rather than OTC.
Ex-dividend
When the next coupon or other payment due on a security is paid to the seller of a security after he/she has sold
it, rather than to the buyer, generally because the transaction is settled after the record date. See cum-dividend.
Exercise
To exercise an option (by the holder) is to require the
other party (the writer) to fulfil the underlying transaction. Exercise price is the same as strike price.
Expiry
An option’s expiry is the time after which it can no
longer be exercised.
Exposure
Risk to market movements.
Extrapolation
The process of estimating a price or rate for a particular
value date, from other known prices, when the value date
required lies outside the period covered by the known
prices. See interpolation.
Face value
(Or nominal value). The principal amount of a security,
generally repaid (“redeemed”) all at maturity, but sometimes repaid in stages, on which the coupon amounts are
calculated.
Fence
Same as collar.
Floating rate
In interest rates, an instrument paying a floating rate is
one where the rate of interest is refixed in line with
market conditions at regular intervals such as every three
or six months.
In the currency market, an exchange rate determined by
market forces with no government intervention.
Floating rate CD
(Or FRCD). CD on which the rate of interest payable is
refixed in line with market conditions at regular intervals
(usually six months).
367
Mastering Financial Calculations
Floating rate note
(Or FRN). Capital market instrument on which the rate
of interest payable is refixed in line with market conditions at regular intervals (usually six months).
Floor
A series of lender’s IRGs, designed to protect an investor
against falling interest rates on each of a series of dates.
Forward
In general, a deal for value later than the normal value
date for that particular commodity or instrument. In the
foreign exchange market, a forward price is the price
quoted for the purchase or sale of one currency against
another where the value date is at least one month after
the spot date. See short date.
Forward exchange
agreement
(Or FXA). A contract for differences designed to create
exactly the same economic result as a foreign exchange
cash forward-forward deal. See ERA, SAFE.
Forward-forward
An FX swap, loan or other interest-rate agreement starting on one forward date and ending on another.
Forward rate agreement (Or FRA). A contract for differences based on a forwardforward interest rate.
FRA
See forward rate agreement.
FRCD
See floating rate CD.
FRN
See floating rate note.
Funds
The USD/CAD exchange rate for value on the next business day (standard practice for USD/CAD in preference
to spot).
Future value
The amount of money achieved in the future, including
interest, by investing a given amount of money now. See
time value of money, present value.
Futures contract
A deal to buy or sell some financial instrument or commodity for value on a future date. Unlike a forward deal,
futures contracts are traded only on an exchange (rather
than OTC), have standardized contract sizes and value
dates, and are often only contracts for differences rather
than deliverable.
FXA
See forward exchange agreement.
Gamma (Γ)
The change in an option’s delta relative to a change in the
underlying’s value.
Gross redemption yield The same as yield to maturity; “gross” because it does
not take tax effects into account.
GRY
368
See gross redemption yield.
Appendix 4 · Glossary
Hedge ratio
The ratio of the size of the position it is necessary to take
in a particular instrument as a hedge against another, to
the size of the position being hedged.
Hedging
Protecting against the risks arising from potential market
movements in exchange rates, interest rates or other variables. See cover, arbitrage, speculation.
Historic rate rollover
A forward swap in FX where the settlement exchange
rate for the near date is based on a historic off-market
rate rather than the current market rate. This is prohibited by many central banks.
Historic volatility
The actual volatility recorded in market prices over a particular period.
Holder
The holder of an option is the party that has purchased it.
Immunization
The construction of a portfolio of securities so as not to
be adversely affected by yield changes, provided it is held
until a specific time.
Implied repo rate
The break-even interest rate at which it is possible to sell
a bond futures contract, buy a deliverable bond, and repo
the bond out. See cash-and-carry.
Implied volatility
The volatility used by a dealer to calculate an option
price; conversely, the volatility implied by the price actually quoted.
Index swap
Sometimes the same as a basis swap. Otherwise a swap
like an interest rate swap where payments on one or both
of the legs are based on the value of an index – such as an
equity index, for example.
Indirect
An exchange rate quotation against the US dollar in
which the dollar is the base currency and the other currency is the variable currency.
Initial margin
See margin.
Interest rate guarantee
(Or IRG). An option on an FRA.
Interest rate swap
(Or IRS). An agreement to exchange a series of cashflows
determined in one currency, based on fixed or floating interest payments on an agreed notional principal, for a series of
cashflows based in the same currency but on a different
interest rate. May be combined with a currency swap.
Internal rate of return
(Or IRR). The yield necessary to discount a series of
cashflows to an NPV of zero.
Interpolation
The process of estimating a price or rate for value on a
particular date by comparing the prices actually quoted
for value dates either side. See extrapolation.
369
Mastering Financial Calculations
370
Intervention
Purchases or sales of currencies in the market by central
banks in an attempt to reduce exchange rate fluctuations
or to maintain the value of a currency within a particular
band, or at a particular level. Similarly, central bank
operations in the money markets to maintain interest
rates at a certain level.
In-the-money
A call (put) option is in-the-money if the underlying is
currently more (less) valuable than the strike price. See
at-the-money, out-of-the-money.
IRG
See interest rate guarantee.
IRR
See internal rate of return.
IRS
See interest rate swap.
Iteration
The repetitive mathematical process of estimating the
answer to a problem, by trying how well this estimate fits
the data, adjusting the estimate appropriately and trying
again, until the fit is acceptably close. Used, for example,
in calculating a bond’s yield from its price.
Kappa (κ)
Same as vega.
Knock out / in
A knock out (in) option ceases to exist (starts to exist) if the
underlying reaches a certain trigger level. See barrier option.
Lambda (λ)
Same as vega.
Liability swap
An interest rate swap or currency swap used in conjunction with an underlying liability such as a borrowing. See
asset swap.
LIBID
See LIBOR.
LIBOR
London inter-bank offered rate, the rate at which banks
are willing to lend to other banks of top creditworthiness.
The term is used both generally to mean the interest rate
at any time, and specifically to mean the rate at a particular time (often 11:00 am) for the purpose of providing a
benchmark to fix an interest payment such as on an
FRN. LIBID is similarly London inter-bank bid rate.
LIMEAN is the average between LIBID and LIBOR.
LIMEAN
See LIBOR.
Limit up / down
Futures prices are generally not allowed to change by
more than a specified total amount in a specified time, in
order to control risk in very volatile conditions. The maximum movements permitted are referred to as limit up
and limit down.
Lognormal
A variable’s probability distribution is lognormal if the
logarithm of the variable has a normal distribution.
Appendix 4 · Glossary
Long
A long position is a surplus of purchases over sales of a
given currency or asset, or a situation which naturally
gives rise to an organization benefiting from a strengthening of that currency or asset. To a money market dealer,
however, a long position is a surplus of borrowings taken
in over money lent out, (which gives rise to a benefit if
that currency weakens rather than strengthens). See short.
Macaulay duration
See duration.
Margin
Initial margin is collateral, placed by one party with a
counterparty at the time of a deal, against the possibility
that the market price will move against the first party,
thereby leaving the counterparty with a credit risk.
Variation margin is a payment or extra collateral transferred subsequently from one party to the other because
the market price has moved. Variation margin payment is
either in effect a settlement of profit/loss (for example, in
the case of a futures contract) or the reduction of credit
exposure (for example, in the case of a repo). In gilt repos,
variation margin refers to the fluctuation band or threshold within which the existing collateral’s value may vary
before further cash or collateral needs to be transferred.
In a loan, margin is the extra interest above a benchmark
(e.g. a margin of 0.5 percent over LIBOR) required by a
lender to compensate for the credit risk of that particular
borrower.
Margin call
A call by one party in a transaction for variation margin
to be transferred by the other.
Margin transfer
The payment of a margin call.
Mark-to-market
Generally, the process of revaluing a position at current
market rates.
Mean
Average.
Modified duration
A measure of the proportional change in the price of a
bond or other series of cashflows, relative to a change in
yield. (Mathematically –
dP
di
dirty price.) See duration.
Modified following
The convention that if a value date in the future falls on a
non-business day, the value date will be moved to the
next following business day, unless this moves the value
date to the next month, in which case the value date is
moved back to the last previous business day.
Money market
Short-term market (generally up to one year) for financial
instruments. See capital market.
371
Mastering Financial Calculations
372
Money-market basis
An interest rate quoted on an ACT/360 basis is said to be
on a money-market basis. See bond basis.
Moosmüller
A method for calculating the yield of a bond.
Naked
A naked option position is one not protected by an offsetting position in the underlying. See covered call / put.
Negotiable
A security which can be bought and sold in a secondary
market is negotiable.
Net present value
(Or NPV). The net present value of a series of cashflows
is the sum of the present values of each cashflow (some
or all of which may be negative).
Nominal amount
Same as face value of a security.
Nominal rate
A rate of interest as quoted, rather than the effective rate
to which it is equivalent.
Normal
A normal probability distribution is a particular distribution assumed to prevail in a wide variety of circumstances,
including the financial markets. Mathematically, it corre1 2
sponds to the probability density function 1 e – 2 φ .
2π
Notional
In a bond futures contract, the bond bought or sold is a
standardized non-existent notional bond, as opposed to
the actual bonds which are deliverable at maturity.
Contracts for differences also require a notional principal
amount on which settlement can be calculated.
NPV
See net present value.
O/N
See overnight.
Odd date
See broken date.
Offer
(Or ask). In general, the price at which the dealer quoting
a price is prepared to sell or lend. The offer price of a foreign exchange quotation is the rate at which the dealer
will sell the base currency and buy the variable currency.
The offer rate in a deposit quotation is the interest rate at
which the dealer will lend the currency involved. The
offer rate in a repo is the interest rate at which the dealer
will lend the collateral and borrow the cash.
Off-market
A rate which is not the current market rate.
Open interest
The quantity of futures contracts (of a particular specification) which have not yet been closed out by reversing.
Either all long positions or all short positions are counted
but not both.
Option
An option is the right, without any obligation, to undertake a particular deal at predetermined rates. See call, put.
Appendix 4 · Glossary
Option forward
See time option.
OTC
See over the counter.
Out-of-the-money
A call (put) option is out-of-the-money if the underlying
is currently less (more) valuable than the strike price. See
at-the-money, in-the-money.
Outright
An outright (or forward outright) is the sale or purchase
of one foreign currency against another for value on any
date other than spot. See spot, swap, forward, short date.
Over the counter
(Or OTC). An OTC transaction is one dealt privately
between any two parties, with all details agreed between
them, as opposed to one dealt on an exchange – for
example, a forward deal as opposed to a futures contract.
Overborrowed
A position in which a dealer’s liabilities (borrowings taken
in) are of longer maturity than the assets (loans out).
Overlent
A position in which a dealer’s assets (loans out) are of
longer maturity than the liabilities (borrowings taken in).
Overnight
(Or O/N or today/tomorrow). A deal from today until
the next working day (“tomorrow”).
Par
In foreign exchange, when the outright and spot exchange
rates are equal, the forward swap is zero or par.
When the price of a security is equal to the face value,
usually expressed as 100, it is said to be trading at par.
A par swap rate is the current market rate for a fixed
interest rate swap against LIBOR.
Par yield curve
A curve plotting maturity against yield for bonds priced
at par.
Parity
The official rate of exchange for one currency in terms of
another which a government is obliged to maintain by
means of intervention.
Participation forward
A product equivalent to a straightforward option plus a
forward deal, but structured as a forward deal at an offmarket rate plus the opportunity to benefit partially if the
market rate improves.
Path-dependent
A path-dependent option is one which depends on what
happens to the underlying throughout the option’s life
(such as an American or barrier option) rather than only
at expiry (a European option).
Pips
See points.
Plain vanilla
See vanilla.
373
Mastering Financial Calculations
Points
The last two decimal places in an exchange rate. For
example, when USD/DEM is 1.5510 / 1.5520, the points
are 10 / 20. See big figure.
Premium
The amount by which a currency is more expensive, in
terms of another currency, for future delivery than for spot,
is the forward premium (in general, a reflection of interest
rate differentials between two currencies). If an exchange
rate is “at a premium” (without specifying to which of the
two currencies this refers), this generally means that the
variable currency is at a premium. See discount.
An option premium is the amount paid up-front by the
purchaser of the option to the writer.
Present value
The amount of money which needs to be invested now to
achieve a given amount in the future when interest is
added. See time value of money, future value.
Price factor
See conversion factor.
Primary market
The primary market for a security refers to its original
issue. See secondary market.
Probability distribution The mathematical description of how probable it is that
the value of something is less than or equal to a particular level.
374
Put
A put option is an option to sell the commodity or instrument underlying the option. See call.
Quanto swap
A swap where the payments on one or both legs are
based on a measurement (such as the interest rate) in one
currency but payable in another currency.
Quasi-coupon date
The regular date for which a coupon payment would be
scheduled if there were one. Used for price / yield calculations for zero-coupon instruments.
Range forward
A zero-cost collar where the customer is obliged to deal
with the same bank at spot if neither limit of the collar is
breached at expiry.
Record date
A coupon or other payment due on a security is paid by
the issuer to whoever is registered on the record date as
being the owner. See ex-dividend, cum-dividend.
Redeem
A security is said to be redeemed when the principal is
repaid.
Reinvestment rate
The rate at which interest paid during the life of an
investment is reinvested to earn interest-on-interest,
which in practice will generally not be the same as the
original yield quoted on the investment.
Appendix 4 · Glossary
Repo
(Or RP). Usually refers in particular to classic repo. Also
used as a term to include classic repos, buy/sell-backs and
securities lending.
Repurchase agreement
See repo.
Revaluation
An official one-off increase in the value of a currency in
terms of other currencies. See devaluation.
Reverse
See reverse repo.
Reverse repo
(Or reverse). The opposite of a repo.
Rho (ρ)
The change in an option’s value relative to a change in
interest rates.
Risk reversal
Changing a long (or short) position in a call option to the
same position in a put option by selling (or buying) forward, and vice versa.
Rollover
See tom/next. Also refers to renewal of a loan.
RP
See repo.
Running yield
Same as current yield.
S/N
See spot/next.
S/W
See spot-a-week.
SAFE
See synthetic agreement for forward exchange.
Secondary market
The market for buying and selling a security after it has
been issued. See primary market.
Securities lending
(Or stock lending). When a specific security is lent
against some form of collateral.
Security
A financial asset sold initially for cash by a borrowing
organization (the “issuer”). The security is often negotiable and usually has a maturity date when it is
redeemed.
Same as collateral.
Sell / buy-back
Simultaneous spot sale and forward purchase of a security, with the forward price calculated to achieve an effect
equivalent to a classic repo.
Short
A short position is a surplus of sales over purchases of a
given currency or asset, or a situation which naturally
gives rise to an organization benefiting from a weakening
of that currency or asset. To a money market dealer,
however, a short position is a surplus of money lent out
over borrowings taken in (which gives rise to a benefit if
that currency strengthens rather than weakens). See long.
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Mastering Financial Calculations
Short date
A deal for value on a date other than spot but less than
one month after spot.
Simple interest
When interest on an investment is paid all at maturity or
not reinvested to earn interest on interest, the interest is
said to be simple. See compound interest.
Simple yield to maturity Bond coupon plus principal gain / loss amortized over the
time to maturity, as a proportion of the clean price per
100. Does not take time value of money into account. See
yield to maturity, current yield.
Speculation
A deal undertaken because the dealer expects prices to
move in his favour, as opposed to hedging or arbitrage.
Spot
A deal to be settled on the customary value date for that
particular market. In the foreign exchange market, this is
for value in two working days’ time.
A spot curve is a yield curve using zero-coupon yields.
Spot-a-week
(Or S/W). A transaction from spot to a week later.
Spot/next
(Or S/N). A transaction from spot until the next working
day.
Spread
The difference between the bid and offer prices in a
quotation.
Also a strategy involving the purchase of an instrument
and the simultaneous sale of a similar related instrument,
such as the purchase of a call option at one strike and the
sale of a call option at a different strike.
Square
A position in which sales exactly match purchases, or in
which assets exactly match liabilities. See long, short.
Standard deviation (σ) A measure of how much the values of something fluctuate around its mean value. Defined as the square root of
the variance.
376
Stock lending
See securities lending.
Straddle
A position combining the purchase of both a call and a
put at the same strike for the same date. See strangle.
Strangle
A position combining the purchase of both a call and a
put at different strikes for the same date. See straddle.
Street
The “street” is a nickname for the market. The street
convention for quoting the price or yield for a particular
instrument is the generally accepted market convention.
Strike
(Or exercise price). The strike price or strike rate of an
option is the price or rate at which the holder can insist
on the underlying transaction being fulfilled.
Appendix 4 · Glossary
Strip
A strip of futures is a series of short-term futures contracts
with consecutive delivery dates, which together create the
effect of a longer term instrument (for example, four consecutive 3-month futures contracts as a hedge against a
one-year swap). A strip of FRAs is similar.
To strip a bond is to separate its principal amount and its
coupons and trade each individual cashflow as a separate
instrument (“separately traded and registered for interest
and principal”).
Swap
A foreign exchange swap is the purchase of one currency
against another for delivery on one date, with a simultaneous sale to reverse the transaction on another value date.
See also interest rate swap, currency swap.
Swaption
An option on an interest rate swap or currency swap.
Synthetic
A package of transactions which is economically equivalent to a different transaction (for example, the purchase
of a call option and simultaneous sale of a put option at
the same strike is a synthetic forward purchase).
Synthetic agreement
for forward exchange
(or SAFE). A generic term for ERAs and FXAs.
T/N
See tom/next.
Tail
The exposure to interest rates over a forward-forward
period arising from a mismatched position (such as a twomonth borrowing against a three-month loan).
A forward foreign exchange dealer’s exposure to spot
movements.
Term
The time between the beginning and end of a deal or
investment.
Theta (Θ)
The change in an option’s value relative to a change in
the time left to expiry.
Tick
The minimum change allowed in a futures price.
Time deposit
A non-negotiable deposit for a specific term.
Time option
(Or option forward). A forward currency deal in which
the value date is set to be within a period rather than on
a particular day. The customer sets the exact date two
working days before settlement.
Time value of money
The concept that a future cashflow can be valued as the
amount of money which it is necessary to invest now in
order to achieve that cashflow in the future. See present
value, future value.
Today/tomorrow
See overnight.
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Mastering Financial Calculations
Tom/next
(Or T/N or rollover). A transaction from the next working day (“tomorrow”) until the day after (“next” day –
i.e. spot in the foreign exchange market).
Treasury bill
A short-term security issued by a government, generally
with a zero coupon.
True yield
The yield which is equivalent to the quoted discount rate
(for a US or UK treasury bill, for example).
Tunnel
Same as collar.
Underlying
The underlying of a futures or option contract is the commodity or financial instrument on which the contract
depends. Thus the underlying for a bond option is the
bond; the underlying for a short-term interest rate futures
contract is typically a three-month deposit.
Value date
(Or settlement date or maturity date). The date on which
a deal is to be consummated. In some bond markets, the
value date for coupon accruals can sometimes differ from
the settlement date.
Vanilla
A vanilla transaction is a straightforward one.
Variable currency
(Or counter currency). Exchange rates are quoted in
terms of the number of units of one currency (the variable or counter currency) which corresponds to one unit
of the other currency (the base currency).
Variance (σ2)
A measure of how much the values of something fluctuate around its mean value. Defined as the average of
(value – mean)2. See standard deviation.
Variation margin
See margin.
Vega
(Or epsilon (ε), eta (η), kappa (κ) or lambda (λ)). The
change in an option’s value relative to a change in the
underlying’s volatility.
Volatility
The standard deviation of the continuously compounded
return on the underlying. Volatility is generally annualized. See historic volatility, implied volatility.
Also the price sensitivity of a bond as measured by modified duration.
378
Warrant
An option, generally referring to a call option – often a
call option on a security where the warrant is purchased
as part of an investment in another or the same security.
Writer
Same as “seller” of an option.
Yield
The interest rate which can be earned on an investment,
currently quoted by the market or implied by the current
market price for the investment – as opposed to the
Appendix 4 · Glossary
coupon paid by an issuer on a security, which is based on
the coupon rate and the face value.
For a bond, generally the same as yield to maturity unless
otherwise specified.
Yield to equivalent life
The same as yield to maturity for a bond with partial
redemptions.
Yield to maturity
(Or YTM). The internal rate of return of a bond – the
yield necessary to discount all the bond’s cashflows to an
NPV equal to its current price. See simple yield to maturity, current yield.
YTM
See yield to maturity.
Zero-cost collar
A collar where the premiums paid and received are equal,
giving a net zero cost.
Zero-coupon
A zero-coupon security is one that does not pay a
coupon. Its price is correspondingly less to compensate
for this.
A zero-coupon yield is the yield which a zero-coupon
investment for that term would have if it were consistent
with the par yield curve.
379
APPENDIX 5
ISO (SWIFT) currency codes
Country
Currency
Code
Abu Dhabi
Afghanistan
Ajman
Albania
Algeria
Andorra
Andorra
Angola
Anguilla
Antigua
Argentina
Armenia
Aruba
Australia
Austria
Azerbaijan
Azores
UAE dirham
afghani
UAE Dirham
lek
dinar
French franc
peseta
kwanza
E Caribbean dollar
E Caribbean dollar
peso
dram
florin
Australian dollar
Schilling
manat
Portugese escudo
AED
AFA
AED
ALL
DZD
ADF
ADP
AON
XCD
XCD
ARS
AMD
AWG
AUD
ATS
AZM
PTE
Bahamas
Bahrain
Bangladesh
Barbados
Belarus
Belgium
Belize
Benin
Bermuda
Bhutan
Bolivia
Botswana
Brazil
Brunei
Bulgaria
Burkina Faso
Burundi
Bahama dollar
dinar
taka
Barbados dollar
rouble
Belgian Franc
Belize dollar
CFA franc
Bermuda dollar
ngultrum
boliviano
pula
real
Brunei dollar
lev
CFA franc
Burundi franc
BSD
BHD
BDT
BBD
BYR
BEF
BZD
XOF
BMD
BTN
BOB
BWP
BRL
BND
BGL
XOF
BIF
Cambodia
Cameroon
Canada
Canary Islands
riel
CFA franc
Canadian dollar
Spanish peseta
KHR
XAF
CAD
ESP
381
Mastering Financial Calculations
382
Country
Currency
Code
Cape Verde
Cayman Islands
Central African Republic
Chad
Chile
China
Colombia
Congo
Congo Dem. Rep.
Cormoros
Costa Rica
Croatia
Cuba
Cyprus
Czech Republic
escudo
CI dollar
CFA franc
CFA franc
peso
renmimbi yuan
peso
CFA franc
New zaire/Congolese franc
franc
colon
kuna
peso
Cyprus pound
koruna
CVE
KYD
XAF
XAF
CLP
CNY
COP
XAF
ZRN
KMF
CRC
HRK
CUP
CYP
CZK
Denmark
Djibouti
Dominica
Dominican Republic
Dubai
krone
Djibouti franc
E Caribbean dollar
peso
UAE dirham
DKK
DJF
XCD
DOP
AED
Ecuador
Egypt
El Salvador
Equatorial Guinea
Estonia
Ethiopia
European Union
sucre
Egyptian pound
colon
CFA franc
kroon
birr
European currency unit
ECS
EGP
SVC
XAF
EEK
ETB
ECU
Falkland Islands
Faroe Islands
Fiji Islands
Finland
France
French Pacific Islands
Fujairah
pound
Danish krone
Fiji dollar
markka
franc
CFP franc
UAE dirham
FKP
DKK
FJD
FIM
FRF
XPF
AED
Gabon
Gambia
Germany
Ghana
Gibraltar
Great Britain
Greece
Greenland
Grenada
Guadeloupe
Guatemala
CFA franc
dalasi
Mark
cedi
Gibraltar pound
pound
drachma
Danish krone
E Caribbean dollar
French franc
quetzal
XAF
GMD
DEM
GHC
GIP
GBP
GRD
DKK
XCD
FRF
GTQ
Appendix 5 · ISO (SWIFT) currency codes
Country
Currency
Code
Guinea Republic
Guinea-Bissau
Guyana
Guinean franc
CFA franc
Guyana dollar
GNF
XAF
GYD
Haiti
Honduras
Hong Kong
Hungary
gourde
lempira
Hong Kong dollar
forint
HTG
HNL
HKD
HUF
Iceland
India
Indonesia
Iran
Iraq
Irish Republic
Israel
Italy
Ivory Coast
krona
rupee
rupiah
rial
dinar
punt
shekel
lira
CFA franc
ISK
INR
IDR
IRR
IQD
IEP
ILS
ITL
XOF
Jamaica
Japan
Jordan
Jamaican dollar
yen
dinar
JMD
JPY
JOD
Kazakhstan
Kenya
Kiribati
Korea (North)
Korea (South)
Kuwait
Kyrgizstan
tenge
shilling
Australian dollar
won
won
dinar
som
KZT
KES
AUD
KPW
KRW
KWD
KGS
Laos
Latvia
Lebanon
Lesotho
Liberia
Libya
Liechtenstein
Lithuania
Luxembourg
kip
lat
Lebanese pound
loti
Liberian dollar
dinar
Swiss franc
litas
Luxembourg franc
LAK
LVL
LBP
LSL
LRD
LYD
CHF
LTL
LUF
Macao
Macedonia
Madeira
Malagasy Republic
Malawi
Malaysia
Maldives
Mali
Malta
Martinique
pataca
denar
Portugese escudo
franc
kwacha
ringgitt
rufiyaa
CFA franc
lira
French franc
MOP
MKD
PTE
MGF
MWK
MYR
MVR
XOF
MTL
FRF
383
Mastering Financial Calculations
Country
Currency
Code
Mauritania
Mauritius
Mexico
Moldova
Monaco
Mongolia
Montserrat
Morocco
Mozambique
Myanmar
ouguiya
rupee
peso nuevo
leu
French franc
tugrik
E Caribbean dollar
dirham
metical
kyat
MRO
MUR
MXN
MDL
FRF
MNT
XCD
MAD
MZM
MMK
Namibia
Nauru Isles
Nepal
Netherlands
Netherlands Antilles
New Caledonia
New Zealand
Nicaragua
Niger
Nigeria
Norway
rand
dollar
rupee
guilder
guilder
CFP franc
NZ dollar
cordoba
CFA franc
naira
krone
NAD
NPR
NLG
ANG
XPF
NZD
NIO
XOF
NGN
NOK
Oman
riyal
OMR
Pakistan
Panama
Papua New Guinea
Paraguay
Peru
Philippines
Poland
Portugal
rupee
balboa
kina
guarani
sol nuevo
peso
zloty
escudo
PKR
PAB
PGK
PYG
PEN
PHP
PLN
PTE
Qatar
riyal
QAR
Ras Al Khaimah
Reunion Island
Romania
Russia
Rwanda
~o Tomé
Sa
UAE dirham
French franc
leu
rouble
franc
AED
FRF
ROL
RUR
RWF
dobra
riyal
CFA franc
rupee
UAE dirham
leone
Singapore dollar
koruna
tolar
STD
SAR
XOF
SCR
AED
SLL
SGD
SKK
SIT
Saudi Arabia
Senegal
Seychelles
Sharjah
Sierra Leone
Singapore
Slovakia
Slovenia
384
Appendix 5 · ISO (SWIFT) currency codes
Country
Currency
Code
Solomon Islands
Somalia
South Africa
Spain
Sri Lanka
St Christopher
St Helena
St Kitts & Nevis
St Lucia
St Pierre et Miquelon
St Vincent
Sudan
Sudan
Surinam
Swaziland
Sweden
Switzerland
Syria
dollar
shilling
rand
peseta
rupee
E Caribbean dollar
pound
E Caribbean dollar
E Caribbean dollar
French franc
E Caribbean dollar
dinar
Sudanese pound
Surinam guilder
lilangeni
krona
Swiss franc
Syrian pound
SBD
SOS
ZAR
ESP
LKR
XCD
SHP
XCD
XCD
FRF
XCD
SDD
SDP
SRG
SZL
SEK
CHF
SYP
Taiwan
Tajikistan
Tanzania
Thailand
Togo
Tonga
Trinidad & Tobago
Tunisia
Turkey
Turkmenistan
dollar
sum
shilling
baht
CFA franc
pa’ anga
TT dollar
dinar
lira
manat
TWD
TJS
TZS
THB
XOF
TOP
TTD
TND
TRL
TMM
Uganda
Ukraine
Um Al Quwain
United Arab Emirates
Uruguay
USA
Uzbekistan
shilling
hryvna
UAE dirham
dirham
peso
US dollar
sum
UGX
UAH
AED
AED
UYP
USD
UZS
Vanuatu
Venezuela
Vietnam
Virgin Islands (USA)
vatu
bolivar
dong
US dollar
VUV
VEB
VND
USD
Wallis & Futuna Islands
Western Samoa
CFP franc
tala
XPF
WST
Yemen
Yugoslavia
rial
dinar
YER
YUM
Zambia
Zimbabwe
kwacha
Zimbabwe dollar
ZMK
ZWD
385
SELECT BIBLIOGRAPHY
General
Adams, A. Bloomfield, D. Booth, P. and England, P. (1993) Investment Mathematics
and Statistics, Graham & Trotman, London.
Blake, D. (1990) Financial Market Analysis, McGraw Hill, Maidenhead.
Risk Magazine, monthly periodical, Risk Publications Ltd.
Money market
Stigum, M. (1981) Money Market Calculations : Yields, Break-evens and Arbitrage,
Dow Jones Irwin, Illinois.
Quarterly Review, quarterly periodical, LIFFE, London.
Bond market calculations
Fabozzi, F. (1988) Fixed Income Mathematics, Probus, Illinois.
Steiner, R. (1997) Mastering Repo Markets, FT Pitman, London.
Corrigan, D. Georgiou, C. and Gollow, J. (1995) Natwest Markets Handbook of
International Repo, IFR Publishing, London.
Swaps
Marshall, J. and Kapner, K. (1993) Understanding Swaps, John Wiley, Chichester.
Price, J. and Henderson, S. (1988) Currency and Interest Rate Swaps, Butterworths,
London.
Options
Wilmot, P. Howison, S. and Dewynne, J. (1995) The Mathematics of Financial
Derivatives, Cambridge University Press, Cambridge.
Hull, J. (1989) Options, Futures and Other Derivative Securities, Prentice-Hall, New
Jersey.
Cox, J. and Rubinstein, M. (1985) Options Markets, Prentice-Hall, New Jersey.
387
INDEX
Black-Scholes model 228–30, 234–6,
accrued interest 89–90
353–4
ACT conventions see day/year
BOBLS (Bundesobligationen) 83
conventions
bond futures 114–29, 346
Alpine bonds 82
arbitrage structure 125–7
American options 223
basis concept 127–8
amortisation 85
basis risk 129
amortising swap 213–14
buying the basis 128
annuities 17
cash-and-carry arbitrage 121–7,
APR (annualized percentage rate) 10
347
arbitrage
cheapest to deliver (CTD) bonds
between different borrowing
115, 116, 125
markets 198–9
contract specification 114–15
cash-and-carry arbitrage 121–7, 347
conversion factors 115–16, 127–8
covered interest arbitrage 165–7,
and coupon payments 116
350, 351
deliverable bonds 115–16
and forward rate agreements
delivery dates 116
(FRAs) 59, 75–6, 181–6
forward bond prices 118–19
and interest rate futures 75–6
hedge ratio 347
linking different markets 30
hedging cash positions 119–21
round-tripping arbitrage 156
implied repo rate 124–5
arithmetic mean 225
net basis 128
Asian options 252
net cost of carry 128
asset swaps 199, 211–12
pricing 116–18
asset-backed securities 86
repos (repurchase agreements)
automated pit trading 66
121–5, 347
average rate options 252
selling the basis 128
average strike options 252
bond warrants 85
bond-equivalent yields 43, 99–101,
barrier options 252
basis risk 73, 74, 127–8, 129
344–5
bonds
basis swap 200
calculations summary 343–7
BBA (British Bankers’ Association)
comparing different bonds 142–3
settlement rates 177
convexity 111–13, 345–6
bear spreads 249
discounting cashflows 86–9, 106
bearer securities 31
domestic bonds 82
bills of exchange 37
duration 107–9, 345–6
binary options 252
DV01 (dollar value of an 01) 111
binomial tree 231–6
389
Mastering Financial Calculations
euro bonds 82
Eurobonds 82
foreign bonds 82
government bond markets 82–4
immunization against yield changes
108–9
modified duration 109–11, 121
portfolio duration 113–14
sensitivity of price to yield changes
109–11, 111–13
types of bonds 84–6
yield calculations 95–105
see also pricing bonds; zero-coupon
bonds
bootstrapping 139–40, 142
break forward 244–5
British Bankers'’ Association (BBA)
settlement rates 177
BTANs 84
bull spreads 249
Bulldog bonds 82
Bundesobligationen (OBLs) 83
Bunds 83
buying the basis 128
calculators 4, 329–35
addition/subtraction 330–1
algebraic/RPN modes 330
chaining 332
date calculations 333–5
decimal places 330
deleting entries 330
exponents 332
function menus 333
multiplication/division 331
reciprocals 333
square roots 333
types of HP calculators 329
calendar spreads 76–7, 250
call bonds 85
call options 223, 246–8
call spread purchase 249
capital markets 82
see also bonds
caps 243–4
cash-and-carry arbitrage 121–7, 347
cashflow analysis 15–17
390
annuities 17
internal rate of return (IRR)
16–17, 18–22, 340
net present value (NPV) 15–16,
18–22, 340
certificates of deposit (CD) 35,
38–40, 87–8, 102, 341
paying more than one coupon
43–6, 342
cheapest to deliver (CTD) bonds
115, 116, 125
clean prices 89–90, 94–5
clearing houses 66
collars 244
commercial paper (CP) 36
compound interest 5
compound options 252
contingent options 252
continuous compounding 8–9, 340
conversion factors for bond futures
115–16, 127–8
convertible gilts 83
convexity 111–13, 345–6
corridors 244
coupon payments 31
and bond futures 116
and bond pricing 90, 96–7
on certificates of deposit 87
yield in final coupon periods 98–9,
344
coupon swap 200
covered call/put option writing 247–8
covered interest arbitrage 165–7,
350, 351
credit risk 68
cross-market spreads 77
cross-rate forwards 167–73
outrights 167–8, 169
swaps 168–71
terminology 169
cross-rates 151, 152, 153–5, 348–9
cum-dividend periods 91
currency futures
pricing theory 64
yen/dollar contract 65
currency options 230, 237, 352
currency swaps 216–17
Index
current yield 97
cylinders 244
day/year conventions
and bonds 91–3, 106
in foreign exchange markets 32–3
and interest rate swaps 200–1
in the money markets 32–4, 336–8
summary 336–8
delayed-start swap 215
deliverable bonds 115–16
delivery of futures contracts 64, 67,
68, 116
delta 238–40
digital options 252
direct foreign exchange quotes 151,
152
dirty prices 89, 343–4
discount factors 14–15
discount instruments 31, 40–3, 341
discount rates 41–3, 342
discounting cashflows 11–14,
15–16, 18–22, 86–9, 106, 340
discounting future foreign exchange
risk 186–8
discounts in forward exchange rates
159–61, 171, 349–50
domestic bonds 82
duration 107–9, 345–6
modified duration 109–11, 121
portfolio duration 113–14
DV01 (dollar value of an 01) 111
effective interest rates 6–7, 10–11,
34, 339
ERAs (exchange rate agreements)
177, 180–1, 188
euro bonds 82
Eurobonds 82
Eurocurrencies 31
EuroDEM 3–month contract 64–5
European options 223
ex-dividend periods 91
exchange rate agreements (ERAs)
177, 180–1, 188
exchange rates see foreign exchange
markets
exchange-traded options 237–8
exotic options 252–3
extrapolation 22–3, 341
Fanny Mae 83
Federal Home Loan Mortgage
Corporation (FHMC) 83
Federal National Mortgage
Association (FNMA) 83
Federal Treasury notes (Schätze) 83
floating rate notes (FRNs) 84
floors 243–4
foreign bonds 82
foreign exchange agreements (FXAs)
176–7, 178–80
arbitrage and creating FRAs 181–6
foreign exchange markets
calculation summary 348–51
cross-rate forwards 167–73
cross-rates 151, 152, 153–5, 348–9
currency futures 64, 65
currency options 230, 237, 352
currency swaps 216–17
day/year conventions 32–3
discounting future foreign
exchange risk 186–8
exchange rate agreements (ERAs)
177, 180–1, 188
foreign exchange agreements
(FXAs) 176–7, 178–80
arbitrage and creating FRAs
181–6
forward exchange rates 156–67, 349
forward-forward swaps 172–5, 350
guaranteed exchange rate options
253
ISO (SWIFT) currency codes 377–81
and money markets 30
quoted spot rates 150, 151–3
settlement of spot transactions 150
spot exchange rates 150–3
spreads 152
synthetic agreements for forward
exchange (SAFES) 176–7, 350–1
time options 175–6, 350
value dates 172–3
formulas 4
391
Mastering Financial Calculations
notation 339
forward bond prices 118–19
forward exchange rates 156–67, 349
covered interest arbitrage 165–7,
350, 351
discounts and premiums 159–61,
171, 349–50
forward outrights 156–7, 171–2,
176, 350
forward swaps 157–63
as an interest rate position 161–2
bid/offer spreads 160
compared to forward outrights
161–3, 166
quotations 160–1
settlement 162
historic rate rollovers 164–5
and interest rates 159–60, 165
round-tripping arbitrage 156
forward with optional exit 244–5
forward outrights 156–7, 161–3,
166, 171–2, 176, 350
forward rate agreements (FRAs) 52,
53–6, 342–3
and arbitrage 59, 75–6, 181–6
and hedging 58–9, 69–73, 196–7
and interest rate swap pricing
203–7
pricing 54, 67–8, 71
longer-dated issues 143–5
quotations 54
settlement 55–6, 68
and speculation 59
forward swaps 157–63
as an interest rate position 161–2
bid/offer spreads 160
compared to forward outrights
161–3, 166
quotations 160–1
settlement 162
forward-forward swaps 172–5, 350
forward-forwards 52–3, 342–3
forward-start swap 215
Freddie Mac 83
French government bonds 84
FRNs (floating rate notes) 84
future value 11–14, 340
392
futures contracts 52, 64
basis risk 73, 74
compared to OTC contracts 68–9
credit risk 68
currency futures 64, 65
delivery 64, 67, 68
exchange structure 66–7
limits on trading movements 67
liquidity 69
margin requirements 67, 68
open interest 74–5
pricing 64
settlement 68
trading strategies 75–8
volume 74–5
see also bond futures; interest rate
futures
FXAs see foreign exchange agreements
gamma 240
German government bonds 83
gilts 83
Ginny Mae 83
government bond markets 82–4
Government National Mortgage
Association (GNMA) 83
gross redemption yield (GRY) 95
guaranteed exchange rate options 253
hedging
basis risk 73
borrowing costs 196–7
caps and floors 243–4
cash positions 119–21
delta hedging 239–40
forward rate agreements (FRAs)
58–9, 69–73
hedge ratio 347
an interest rate swap 213
interest rate guarantees (IRGs) 243
modified duration hedging 121
with options 222, 239–40, 242–4
historic rate rollovers 164–5
HP (Hewlett Packard) calculators see
calculators
immunization against yield changes
108–9
Index
implied repo rate 124–5
index swap 200
index-linked bonds 83, 84
indirect foreign exchange quotes
151, 152, 153
interest rate futures 64–78, 343
and arbitrage 75–6
basis risk 73, 74
calendar spreads 76–7
contract specification 65–6
cross-market spreads 77
EuroDEM 3-month contract 64–5
hedging
basis risk 73
forward rate agreements 69–73
pricing 67
and speculation 75
strip trading 77–8
volume and open interest 74–5
see also futures contracts
interest rate guarantees (IRGs) 243
interest rate swaps 139–40
amortising swap 213–14
asset swaps 199, 211–12
basis swap 200
coupon swap 200
delayed-start swap 215
existence of cost discrepancies
197–9
forward-start swap 215
hedging an interest rate swap 213
hedging borrowing costs 196–7
index swap 200
marking-to-market 207–10
pricing 200–7, 352
converting between different
quotation bases 201–3
day/year conventions 200–1
and government bond yields 203
link with FRAs 203–7
longer-term swaps 207
relative advantage in borrowing
197–9
reversing a swap transaction
210–11
and speculation 199
valuing 207–12, 352
interest rates
compound interest 5
continuous compounding 8–9, 340
effective rates 6–7, 10–11, 34, 339
and forward exchange rates
159–60, 165
nominal rates 6–7, 10–11
and option pricing 224
quoted rates
and frequency of payments 10–11
and investment periods 10
reinvestment rates 9, 96, 107
simple interest 5
yield curves 56–7, 136–7, 142–3,
348
see also yields
internal rate of return (IRR) 16–17,
18–22, 340
interpolation 22–3, 341
intrinsic value of options 223
IRGs (interest rate guarantees) 243
IRR (internal rate of return) 16–17,
18–22, 340
irredeemable gilts 83, 85
ISO (SWIFT) currency codes 377–81
Italian bonds 93, 94
LIBOR (London Interbank Offered
Rate) 31–2
LIFFE (London International
Financial Futures Exchange) 237
liquidity 69
loans 34–5
London Clearing House (LCH) 66
margin requirements 67, 68
marking-to-market 207–10
Matador bonds 82
mathematical formulas 4
medium-term notes (MTNs) 86
modified duration 109–11, 121
money market yield 102–3, 345
money markets 30–46
calculations 38–40, 341–2
and capital markets 30
day/year conventions 32–4, 336–8
discount instruments 31, 40–3, 341
and foreign exchange markets 30
terminology 31–2
393
Mastering Financial Calculations
underlying instruments 30, 34–8
Moosmüller yield 103, 345
mortgage-backed securities 86
net basis 128
net cost of carry 128
net present value (NPV) 15–16,
18–22, 340
nominal interest rates 6–7, 10–11
non-working days adjustment 106
Norwegian bonds 94
OATs 84
OBLs (Bundesobligationen) 83
open interest 74–5
open outcry futures dealing 66
options
American style 223
as an insurance policy 222
call options 223, 246–8
currency options 230, 237, 352
delta 238–40
European style 223
exchange-traded 237–8
exotic 252–3
gamma 240
hedging techniques 222, 239–40,
242–4
and interest rates 224
intrinsic value 223
OTC (over-the-counter) 237–8,
244–6
packaged 244–6
premium payments 222, 237–8
pricing
binomial tree 231–6
Black-Scholes model 228–30,
234–6, 353–4
concepts 223–8
sensitivities 355
put options 223, 246–8
put/call relationship 236–7, 354
rho 241–2
risk reversal 236–7
strike price 223, 224
synthetic forwards 236–7
terminology 223
394
theta 241
time options 175–6, 350
time value 223
trading strategies 246–52
vega 240–1
volatility calculations 224, 225,
227–8, 352–3
writing 247–8
OTC (over-the-counter) options
237–8, 244–6
packaged options 244–6
par yields 136–8, 142
participation forward 245–6
perpetual bonds 85
Philadelphia Currency Options
Exchange 237
portfolio duration 113–14
premium payments 222, 237–8
premiums in forward exchange rates
159–61, 171, 349–50
present value 11–14, 340
net present value (NPV) 15–16,
18–22, 340
pricing bonds 86–95, 105–7
accrued interest 89–90
actual and theoretical prices 142–3
calculations summary 343–7
calculator use 93–5
clean prices 89–90, 94–5
coupon dates 90
cum-dividend 91
day/year conventions 91–3, 106
dirty prices 89, 343–4
discounting cashflows 86–9, 106
ex-dividend periods 91
non-working days adjustment 106
and quoted yields 106–7
see also yields
probability densities 226
probability distributions 227
put bonds 85
put options 223, 246–8
put spread purchase 249
put/call relationship 236–7, 354
PV01 (present value of an 01) 111
quanto options 253
Index
quasi-coupon dates 104–5
quoted spot rates 150, 151–3
range forward 244
redemption yield 95
registered securities 31
reinvestment rates 9, 96, 107, 136
repurchase agreements (repo) 37–8,
121–4, 121–5, 347
implied repo rates 124–5
price calculation 123–4
reverse repos 122–3
reversing a swap transaction 210–11
rho 241–2
risk reversal 236–7
round-tripping arbitrage 156
SAFES (synthetic agreements for
forward exchange 176–7,
350–1
Sally Mae 83
Samurai bonds 82
Schätze (Federal Treasury notes) 83
selling the basis 128
settlement
of forward rate agreements (FRAs)
55–6, 68
of futures contracts 68
of spot foreign exchange
transactions 150
simple interest 5
and bond pricing 106
simple yield to maturity 97–8
SLMA (Student Loan Marketing
Association) 83
Spanish bonds 93, 94
speculation 59, 75, 199
spot exchange rates 150–3
spot yield curves 136
spread strategies 76–7, 152, 248–50
standard deviation 225
see also volatility calculations
straddles 250–1
strangles 251–2
strike price 223, 224
strips 57–8, 77–8, 85, 104–5, 343
Student Loan Marketing Association
(SLMA) 83
swaps
coupon swap 200
cross-rate forwards 168–71
currency swaps 216–17
delayed-start swap 215
forward swaps 157–63
as an interest rate position 161–2
bid/offer spreads 160
compared to forward outrights
161–3, 166
quotations 160–1
settlement 162
forward-forward swaps 172–5, 350
forward-start swap 215
index swap 200
see also interest rate swaps
swaptions 253
synthetic agreements for forward
exchange (SAFES) 176–7, 350–1
synthetic forwards 236–7
theta 241
time deposits 34–5
time options 175–6, 350
time value
of money 11–14, 17
of options 223
trading strategies
for futures contracts 75–8
for options 246–52
treasury bills (T-bills) 35–6, 40
bond-equivalent yields 99–101
treasury bonds 83, 99, 101
treasury notes 83
true yield 41–3
tunnels 244
UK government securities 83, 99
US government bonds 83
value dates 172–3
vega 240–1
volatility calculations 224, 225,
227–8, 352–3
volume 74–5
warrants 85
395
Mastering Financial Calculations
writing mathematical formulas 4
and present/future value 11–12
writing options 247–8
redemption yield 95
Yankee bonds 82
and reinvestment rates 9, 96, 107
yen/dollar contract 65
simple yield to maturity 97–8
yield curves 56–7, 136–7, 142–3, 348
true yield 41–3
yield to maturity (YTM) 95–6, 142
yield to maturity (YTM) 95–6, 142
yields
zero-coupon yields 136–43, 348
bond-equivalent yields 43, 99–101,
344–5
zero-coupon bonds 84–5
clean prices 89–90, 94–5
concept of duration 108
constructing par yields from 136–8
and coupon rates 31, 96–7
coupon rates 10, 11
current yield 97
and forward-forward yields 140–2,
dirty prices 89, 343–4
143
on discount instruments 41–3
pricing 104–5
in final coupon period 98–9, 106,
yield calculations
344
from coupon bearing yields
money market yield 102–3, 345
138–40
Moosmüller yield 103, 345
summary 348
par yields 136–8, 142
396
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sold worldwide. In addition, it specializes in advising international companies on treasury risk management. Services range from reviewing management policies and
procedures, through the development of appropriate hedging strategies, to short-term
market advice on foreign exchange and the international money markets.
Among the subjects covered in Markets International’s workshops on financial markets and banking, are:
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Financial mathematics
Foreign exchange and interest rate risk management
Repos
Corporate exposure management
Technical analysis
Accounting for derivatives
Credit analysis
The company also runs workshops aimed specifically at the following ACI exams:
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Financial Calculations
The ACI Diploma
Pre-Diploma (Introduction to Foreign Exchange and Money Markets)
Repos
For further information on in-house training opportunities, or open courses, please contact:
Robert Steiner,
Managing Director,
Markets International Ltd,
111 The Promenade, Cheltenham, Glos GL50 1NW, UK.
Telephone: 01242 222134
Fax: 01242 260793
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