The purchasing power parity exchange rate (direct form) is defined as:
| Cost of a market basket of goods and services in domestic currency | |
| PPP = | ________________________ |
| Cost of the same market
basket of goods and services in foreign currency |
If the foreign economy is experiences a rate of inflation
of
F and the domestic
economy experiences a rate of inflation of
D
then the PPP exchange rate after one year, call it PPP', will be:
(1+ D) | ||
| PPP' = | ___________ | PPP |
(1+ F) |
Thus the ratio of next year's exchange rate to this year's exchange rate, PPP'/PPP = 1+g, is given by:
(1+ D) | ||
| 1+g = | ___________ | |
(1+ F) |
The proportional rate of change of the exchange rate (the value of a unit of foreign currency in terms of the domestic currency) is thus:
( D - F) | ||
| g = | ________ | |
(1+ F) |
Thus when the rates of inflation are small the rate of change of the
exchange rate, g, is approximately equal to the difference in the expected rates
of inflation, (
D -
F).
Current rates of inflation in various countries.
Use current exchange rates and take expected rates of inflation to be the 1997 rates of inflation to forecast next year's exchange rates for the currencies of five pairs of countries.
The forward rate is widely accepted as an unbaised estimate of what the future spot rate is expected to be; i.e.,
The expected rate of change of the exchange rate is thus,
Fisher's Theory of Interest Rates
The computation of the real rate of return from the nominal rate and the rate of inflation has been covered in class. The formula derived was that
)/(1 +
),where r is the nominal rate,
is the
rate of inflation, and r* is the
real interest rate. When the rate of inflation is small the real rate is
approximately equal to (r-
), but for high rates of inflation it is important
to use the above formula. Although the above formula is not difficult to
remember there is a general method for adjusting interest rates which is
even simpler and includes this as a special case. The inflation
adjustment can be expressed in the following form:
);i.e., the nominal rate r that has to be obtained in order to achieve a
real rate r* when the rate of inflation is
is found by the above relation.
If the nominal rate, r, and the rate of inflation,
, are known then r* can
be found from:
) Another adjustment in the interest rate that often has to be made is for risk. Suppose rf is the risk-free nomimal rate. To take into account the element of risk in particular investment it is reasonable to consider there being a risk-premium that should be added to the risk-free rate. Let rp be the risk premium and let rR be the interest rate adjusted for risk. Instead of taking rR to be rf+rp, the more appropriate way to compute rR is:
This also provides the means of determining what risk premium was applied if we know rR and rf. For example, if rR= 0.16 and rf=0.08 then the risk premium is not exactly 8 percent, instead
1 + rp = (1 + rR)/(1 + rf) = 1.16/1.08 = 1.074.
Thus the risk premium rp= 0.074, approximately equal to 0.08 but not quite the same. The significance of this method is what happens if the risk-free rate is different, say rf=0.09. Then we find that
(1 + rR) = (1.09)(1.074) = 1.17066.
In this case the new risk adjusted interest rate is about 17.1 percent instead of 17 percent as the naive risk adjustment would have suggested. In cases where the risk-free rate and the risk premium are at higher levels the difference could be more significant.
The reason for stressing the exact method of computing the risk adjusted interest rate is that for computing the NPV for an international investment there are two methods of making the calculation and if the exact risk adjustment is used then both methods give exactly the same answer. Without the exact adjustment we would find they gave approximately the same answer, which would suggest that one was right and the other was not right.
The two methods illustrated in Homework Assignment #1 are:
I. Forecast the guilder/dollar exchange rate for all future cashflows. Use these exchange rates to convert guilder cashflows into dollars. Discount the dollar and equivalent dollar cash flows at the risk adjusted discount rate for dollars of 16 percent to get the present values. Total to get the NPV for the project.
II. Discount the guilder cash flows at the risk adjusted discount rate for guilders and total to get the present value of the guilder cash flows. Convert the present value of the guilder cashflows into dollars using the known current guilder/dollar exchange rate. Combine this with the present value of the dollar cashflows to get the NPV for the project.
The net present value should be the same using either method. The internal rate of return is the discount rate required to make the NPV equal to zero. It should be the same using either of the two methods.
An Illustration of the Problems of International Investment From Richard Brealey and Stewart Myers, Principles of Corporate Finance.
Outland Steel has an investment opportunity in the Netherlands. Its cash flows in guilders and dollars are:
| YEAR | CASH FLOW | FORECAST EXCHANGE RATE | EQUIVALENT
$ CASH FLOW | PRESENT VALUE |
|
|---|---|---|---|---|---|
| (000s guilders) | (000s $) | (g/$) | (000s $) | (000s $) | |
| 0 | 0 | -700 | 2.00 | _____ | _____ |
| 1 | 400 | 0 | 2.02 | _____ | _____ |
| 2 | 450 | 0 | 2.04 | _____ | _____ |
| 3 | 510 | 0 | 2.06 | _____ | _____ |
| 4 | 575 | 0 | 2.08 | _____ | _____ |
| 5 | 650 | 0 | 2.10 | _____ | _____ |
The riskfree interest rate in the U.S. is 8 percent and the rate of inflation is 5 percent. In the Netherland the riskfree rate is 9 percent.
Outland estimates that the appropriate cost of capital for this investment, considering the risks, is 16 percent dollar return.
Net Present Value Calculator for Internet Explorer.
A Present Value Calculator for Netscape and Internet Explorer.
If FL/$/SL/$ is not known, we can find it because, from the diagram, we know that it is the same as
E(1+
L)/
E(1+
$) which is the same as
(1+rL)/(1+r$).
Once we know the growth factor for the exchange rate (1+g) then we can estimate the exchange rate new year by:
For the second year in the future we apply the same growth factor to the estimate of the exchange rate next year, and so on to the third, fourth and beyond years.
Southern Cross Airlines
North Star Airlines, an American company, has the opportunity of creating an airline in the southern hemisphere serving Perth, Australia; Capetown, South Africa; and Rio de Janiero, Brazil. The project will require an initial investment of $10 million. The project involves some leases which run for seven years so the period of analysis is seven years. The following are the cash flows generated in the various countries and their currencies (U.S. dollars, Australian dollars, South African rand, and Brazilian reales) over the life of the project:
| TIME | CASH FLOW | ||||
|---|---|---|---|---|---|
| U.S. | Australia | South Africa | Brazil | ||
| ($millions) | ($A millions) | (million Rand) | (million Reales) | ||
| 0 | -10.0 | 0.0 | 0.0 | 0.0 | |
| 1 | 0.0 | 0.6 | 1.5 | 1.0 | |
| 2 | 0.0 | 0.6 | 1.5 | 2.0 | |
| 3 | 0.0 | 0.6 | 1.6 | 2.5 | |
| 4 | 0.0 | 0.7 | 1.7 | 3.0 | |
| 5 | 0.0 | 0.7 | 1.8 | 3.5 | |
| 6 | 0.0 | 0.7 | 1.9 | 4.0 | |
| 7 | 1.0 | 0.7 | 2.0 | 4.0 |
At time 0 the exchange rates are 1.4 A$/$, 4 R/$, and 0.5 Rl/$. In the U.S. the risk-free interest rate is 4.0 percent and expected to remain at that level over the life of the project. The expected rate of inflation in the U.S. over the life of the project is 1.0 percent. The risk-free rates in Australia, South Africa, and Brazil are 4.5 percent, 7.0 percent, and 20.0 percent, respectively. Estimate the expected rates of inflation in the three countries. Estimate the rates of changes in the exchange rates.
Exercises:
Net Present Value Calculator for Internet Explorer.
A Present Value Calculator for Netscape and Internet Explorer.
| TIME | CASH FLOW | ||||
|---|---|---|---|---|---|
| U.S. | Colombia | Chile | Agentina | ||
| ($millions) | (C pesos billions) | (Ch pesos billions) | (Arg pesos millions) | ||
| 0 | -15.0 | 0.0 | 0.0 | 0.0 | |
| 1 | 0.0 | 1.6 | 2.0 | 1.0 | |
| 2 | 0.0 | 1.6 | 2.5 | 2.0 | |
| 3 | 0.0 | 1.6 | 3.0 | 2.5 | |
| 4 | 0.0 | 1.8 | 3.0 | 3.0 | |
| 5 | 0.0 | 1.8 | 3.0 | 3.2 | |
| 6 | 0.0 | 2.0 | 3.0 | 3.5 | |
| 7 | 1.0 | 2.0 | 3.0 | 4.0 |
Cash Flows U.S. Col Chile Arg Time ($ mill) (pesos bill) (pesos bill) (pesos mill) 0 -15.0 0 0 0 1 0 1.6 2.0 1.0 2 0 1.6 2.5 2.0 3 0 1.6 3.0 2.5 4 0 1.8 3.0 3.0 5 0 1.8 3.0 3.2 6 0 2.0 3.0 3.5 7 1.0 2.0 3.0 4.0
At time 0 the exchange rates are 800 CP/$, 400 ChP/$, and 1.0 AP/$. In the U.S. the risk-free interest rate is 4.0 percent and expected to remain at that level over the life of the project. The expected rate of inflation in the U.S. over the life of the project is 1.0 percent. The risk-free rates in Colombia, Chile, and Argentina are 15 percent, 7.0 percent, and 10.0 percent, respectively. Estimate the expected rates of inflation in the three countries. Estimate the rates of changes in the exchange rates.
Net Present Value Calculator for Internet Explorer.
A Present Value Calculator for Netscape and Internet Explorer.
A call option is the right to buy a share of a stock at a specified price, called the exercise price or strike price. There is an expiration date for the option. American options can be exercised any time up to the end of the expiration day, whereas European options can only be exercised on the expiration day. This may be less significant than it seems to be.
A put option is the right to sell a share at a specified price subject to a specified expiration day. You may buy an option or you may sell an option. If you buy an option you must pay a fee, but you have the right to exercise it or not. If you sell an option, you receive a fee, but you do not have control over whether it is exercised.
The social purpose of the options market is to transfer risk from those who do not want to accept a risk to those who are willing to do so for a fee. Both parties may gain from such a transaction. For example, if someone holds shares of a stock and is afraid the price will go down he or she can buy a put to protect against a price decline. Although the vast majority of those who participate in the options market are simply speculators, their participation facilitates the transfer of risk.
The key to the understanding of options is a set of graphs showing the payoff to the option holder as a function of the market price of the stock. In the following analysis the fee for the option is ignored.
Suppose you have an American call option on Orca Systems stock with a strike price of $30 with an expiration date today. The current price is about $35. This means that if you exercised the call you could buy a share of Orca at $30 and turn around and sell it for $35. Ignoring brokerage fees this means you would make $5 per share. If the market price were $40 you could make $10 per share. If $45 then the payoff would be $15. However if the market price were $30 or less you would not exercise the call and the payoff would be zero.
The graph of payoff versus exercise price is as follows.

. .
payoff . .
. .
. .
. .
. .
. .
..................................
X Market
Exercise Price
Price
If you had sold a call instead of buying one the payoff function would be:
.
payoff .
.
.
.
.
.
..................................
. X . Market
. Exercise . Price
. Price .
. .
. .
. .
On the other hand, if you own a put on Orca Systems with an exercise price of $30 when the market price is $35, and it expires immediately then the put has no value. But, if the price of Orca falls to $25 then there is $5 to be had by buying the stock for $25 and reselling. If the price of Orca fell to $20 then the payoff from exercising the put is $10 per share.
The diagram for a put is given below:

Payoff . .. . . . . . . . . ...................................... X Market Exercise Price Price
In addition to puts and calls the market includes the shares themselves and short sales. The payoff function for owning a share is as shown. For a owing a share due to a short sale it is the negative of this.

. .
payoff . .
. .
. .
. .
. .
. .
..................................
X Market Price
To run the program you turn on the computer and monitor and let it go through its startup routine. When it is ready to take input type E: to shift it from the C drive to the E drive. On the E drive there a subdirectory for this class entitled econ137b (no space between the econ and the 137B). Type cd econ137B to change the directory from the root directory to the econ137B directory.
Now type callprog and the program will run. Press ENTER to move through the program.
Profit if Run Profit held to exp day Difference 1 _________ _________ ________ 2 _________ _________ ________ 3 _________ _________ ________ 4 _________ _________ ________ 5 _________ _________ ________ 6 _________ _________ ________ 7 _________ _________ ________ 8 _________ _________ ________ 9 _________ _________ ________ 10 _________ _________ ________ 11 _________ _________ ________ 12 _________ _________ ________ 13 _________ _________ ________ 14 _________ _________ ________ 15 _________ _________ ________ 16 _________ _________ ________ 17 _________ _________ ________ 18 _________ _________ ________ 19 _________ _________ ________ 20 _________ _________ ________ Average _________ _________ ________
Value of a one year call option when the strike price is $60 as a function of the current price.
Current Intrinsic Value if Price Value Held to Exp. 1 _________ _________ ________ 2 _________ _________ ________ 3 _________ _________ ________ 4 _________ _________ ________ 5 _________ _________ ________ 6 _________ _________ ________ 7 _________ _________ ________ 8 _________ _________ ________ 9 _________ _________ ________ 10 _________ _________ ________ 11 _________ _________ ________ 12 _________ _________ ________ 13 _________ _________ ________ 14 _________ _________ ________ 15 _________ _________ ________ 16 _________ _________ ________ 17 _________ _________ ________ 18 _________ _________ ________ 19 _________ _________ ________ 20 _________ _________ ________
Value of a one year call option when the strike price is $60 as a function of the current price. Use the Callval program to collect the data on present value. Intrinsic value is the maximum of (Current Price - Exercise Price) and zero. Present Current Intrinsic Value if Price Value Held to Exp. 1 __0________ _________ ________ 2 _10________ _________ ________ 3 _20________ _________ ________ 4 _30________ _________ ________ 5 _40________ _________ ________ 6 _50________ _________ ________ 7 _60________ _________ ________ 8 _70________ _________ ________ 9 _80________ _________ ________ 10 _90________ _________ ________ 11 100________ _________ ________ 12 110________ _________ ________ 13 120________ _________ ________ 14 130________ _________ ________ 15 140________ _________ ________ 16 _________ _________ ________ 17 _________ _________ ________ 18 _________ _________ ________ 19 _________ _________ ________ 20 _________ _________ ________
The risk-premium of the stock, rp, will also affect call value. The program CALLS is set up to allow to choose these variables. Use as a base case S=$65, X=$60, T=1 year, rp=0.08, vol = 0.2, and rf=0.03. The middle item for each case is the base case. You need to do the base case only once and enter the result for the middle item in each case. Hold all variables except one at these base case values and vary that one variable to levels above and below the base case. Sketch a little graph of the results.
| Current Stock Price | Call Price | Delta |
|---|---|---|
| S |
C/ S | |
| $60 | ||
| $65 | ||
| $70 |
Delta | S C _C/_S | $60 _____ _____ | $65 _____ _____ | $70 _____ _____ |___________________ 60 65 70 S Exercise Price | | X C _C/_X | $55 _____ _____ | $60 _____ _____ | $65 _____ _____ |___________________ 55 60 65 X Time to Expiration | Theta | T C _C/_T | 11 months _____ _____ | 12 months _____ _____ | 13 months _____ _____ |___________________ 11 12 13 T Volatility o | Vega | o C _C/_o | 0.1 _____ _____ | 0.2 _____ _____ | 0.3 _____ _____ |___________________ 0.1 0.2 0.3 o Risk-free Interest Rate | Rho | rf C _C/_rf | 0.02 _____ ______ | 0.03 _____ ______ | 0.04 _____ ______ |___________________ 2% 3% 4% rf
Use the B&S progam in the Econ137B subdirectory to compute the value of a call for the following data (which is the same as in Assignment Six) S=$65, X=$60, T=1 year, o=0.2, and rf=0.03.
The middle item for each item below is the base case. You need to do the base case only once and enter the result for the middle item in each case. Hold all variables except one at these base case values and vary that one variable to levels above and below the base case. Sketch a little graph of the results.
Current Stock Price |
Delta |
S C _C/_S |
$60 _____ _____ |
$65 _____ _____ |
$70 _____ _____ |___________________
60 65 70 S
Exercise Price |
|
X C _C/_X |
$55 _____ _____ |
$60 _____ _____ |
$65 _____ _____ |___________________
55 60 65 X
Time to Expiration |
Theta |
T C _C/_T |
0.917 yr _____ _____ |
1.000 yr _____ _____ |
1.083 yr _____ _____ |___________________
11 12 13 T
Volatility o- |
Vega |
o C _C/_o |
0.1 _____ _____ |
0.2 _____ _____ |
0.3 _____ _____ |___________________
0.1 0.2 0.3 o
Risk-free Interest Rate |
Rho |
rf C _C/_rf |
0.02 _____ ______ |
0.03 _____ ______ |
0.04 _____ ______ |___________________
2% 3% 4% rf
Gamma: Gamma is the rate of change of the delta of an option per unit change in stock price; i.e.,
Current Stock Price
Delta Gamma
S _C/_S _Delta/_S
$60-65 _____
_______
$65-70 _____
Perfectly Hedged Portfolios:
A portfolio can be created such that its value is unchanged when the price of the stock changes. Suppose Stock A has a current price of $60 and all of the other data of the base case apply. Consider a portfolio containing 100 written calls with exercise price of $60 plus H share of stock A, where H is equal to the delta of the option.
Price of Stock Value of Stock Value of Calls Value of Portfolio
$60 _________ __________ __________
$65 _________ __________ __________
$70 _________ __________ __________
Newspapers give the price at which options are traded. These options may or may not fit the conditions under which the Black-Scholes formula is valid. In this assignment I want you to pick out a number of options and compare their market values with the values you get using the Black-Scholes program. The current price, exercise price, month of expiration and market value of the options are given in the newspaper listing. Options expire on the third Friday of the month of expiration. Use 3.5 percent for the risk-free interest rate. We do not have convenient estimates of the volatilities of the underlying stocks and so I want you use the average volatility of all stocks, which is 0.215. Then, by trial and error, find the volatility that make the Black-Scholes value equal to the market value. This figure is called the "implicit" volatility for the option.
Company Current Exercise Time to Volatility B&S Market Implicit Name Price Price Expiration Value Price Volatility _____ ______ ______ _______ _____ _____ _____ _______ _____ ______ ______ _______ _____ _____ _____ _______ ______ ______ _______ _______ _____ _____ _____ _______ ______ ______ _______ _______ _____ _____ _____ _______ ______ ______ _______ _______ _____ _____ _____ _______ ______ ______ _______ _______ _____ _____ _____ _______ ______ ______ _______ _______ _____ _____ _____ _______ ______ ______ _______ _______ _____ _____ _____ _______ ______ ______ _______ _______ _____ _____ _____ _______ ______ ______ _______ _______ _____ _____ _____ _______ ______ ______ _______ _______ _____ _____ _____ _______ ______ ______ _______ _______ _____ _____ _____ _______ ______ ______ _______ _______ _____ ____ _____ _______ ______ ______ _______ _______ _____ _____ _____ _______ ______ ______ _______ _______ _____ _____ _____ _______ ______ ______ _______ _______ _____ _____ _____ _______ ______ ______ _______ _______ _____ _____ _____ _______ ______ ______ _______ _______ _____ _____ _____ _______ ______ ______ _______ _______ _____ _____ _____ _______ ______ ______ _______ _______ _____ ____ _____ _______ ______ ______ _______ _______ _____ _____ _____ _______ ______ ______ _______ _______ _____ _____ _____ _______ ______ ______ _______ _______ _____ _____ _____ _______
The procedure for generating prices is to use the rate of return, a random variable with a normal rate of return, to compute the price at one time period from the previous time period; i.e.,
pt = pt-1 (1 + rt).
However in comparing prices at different time periods it is essential to deal in discounted values, thus
PVpt = PVpt-1(1+rt)/(1+rd).
The question is what is the appropriate discount rate rd. Two possibilities are the risk-free interest rate and the expected value of rt.
Complex Options A "long" Straddle is created by buying a put and a call on the same stock with the same exercise price and the same expiration date. A "short" straddle is created by selling (writing) a put and a call instead of buying them. If the exercise price of the call is higher than the exercise price of the put, the combination is fancifully known as a strangle.
A spread involves two of the same type of option (put or call) for the same expiration date but different exercise prices and one being a purchase and one being written. The usual case involves call options, say buying a call at an exercise price of $60 and selling a call with an exercise price of $70.
The terms bulls and bears have a special meaning in the stock market. A bull is someone who thinks the price of a stock is going to go up. A bear is someone who thinks it will go down.
A "bull" spread is a combination of options which will produce a profit for the holder if the price of the underlying stock increases. A "bear" spread is a combination that will produce a profit if the price of the underlying goes down.
A butterfly spread involves four options for the same underlying stock and same expiration date but at three different exercise prices X1, X2, and X3, where X1 < X2 < X3. To create a butterfly one buys a call option at an exercise price of X1, sells two calls at an exercise price of X2, and buys one at an exercise price of X3. This would be called a "long" butterfly spread.
A variation on the butterfly combination involving four different exercise
prices, X1 Another combination involving four exercise prices is the box spread.
A box spread is created by buying one call at X1, selling one
call at X2, buying one put at X3, and selling one put
at X4.
The purpose of this assignment is to gain an acquaintance with the
various speculative devices by keeping track of some and computing the rate
of return for holding them. The more complex ones are constructed as a
combination of simpler ones. Use the options quotations given in the
Wall Street Journal or other comparable newspapers.
I. Create a portfolio of blocks of 100 shares. Select any example of
each of the following:
The selection of the particular stocks and options should not concern
you. The goal is to record the details of the options and compute the
cost of acquiring the options.
Use Khouri's method even though some elements of it are outdated.
A security has value because provides cash payments in the future.
The price of a security should be equal to the present value of the future
cash payments. Typically a security will have a series of interest payments
and one large payment at maturity. For example, a five year bond might
pay $50 per year over the next five years and $1000 at maturity at the
end of the fifth year. This bond would be said to have a face value of
$1000 and a coupon interest rate of 5 percent. The coupon interest rate
is the interest payment as a percent of the face value. The market interest
rate could be an entirely different rate.
The discount factor for money to be received in year T is the amount of
money you would have to put in the bank now so that by year T it would grow
to be equal to $1. In other words, the discount factor for year T is the
present value of $1 in year T. The formula for the discount factor for
year T when the market interest rate is r and is constant over the next
T years is
Discount Factor = 1/(1+r)T.
I. Use a spread sheet such as Quattro Pro or Excel to determine the price of a five year bond with a
face value of $1000 and a coupon interest rate of 5 percent when the market
interest rate is at the following levels: 10 percent, 8 percent, 6 percent,
5 percent, 4 percent, 2 percent.
Compute the discount factor iteratively and use an absolute cell address
for the interest rate so you can change the interest rate without redoing
all of the commands.
II. Use the spreadsheet layout that you created for I to determine
which interest rate will make the present value of the payments on the
five year bond equal to a price of $900. This is called the yield rate.
Determine the yield rate for bond prices of $800 and $1200.
Compute the duration for the bond in part I when the market interest
rate is 4 percent, 6 percent, and 8 percent.
IV. There is relationship between the duration of a security and the
sensitivity of its price to changes in the interest rate. The formula is
(Proportional change in Price) = -Duration
(Change in interest rate) (1+r)
For example, if for the three bond considered above the market
interest increased from 12 percent to 13 percent, the bond price would
decrease from $951.96 by $22.79 to $929.17. This is a 2.4 percent decline
for a 1 percent increase in the interest rate. The ratio is then 2.4.
The duration of 2.7289 divided by 1.12 is also 2.4.
Check the formula for the first two cases in which you computed the
duration in part III. Use a one percent increase in the market interest
rate from 4 percent, and a one percent decrease from 6 percent.
Use the formula to estimate the percentage change in price due to a
two percent increase in the interest rate from 8 percent.
Duration
Some of the cash payment on a security may come in one year, some in
two years, and so on. The duration of a security is the average amount
of time the holder has to wait for the payments. The average is a
weighted average and the weights are the present value of the payments.
For example, for a $1000 three year bond with a coupon interest rate of
10 percent when the market interest rate is 12 percent this is the situation:
Duration = (sum of PVxTime)/(sum of PV) = 2.7289 years
Suppose interest rates are not constant over time but vary from year
to year. For example, suppose the interest rate rises from 5 percent
in the first year to 12 percent in the fourth year and then drops to
10 percent in the fifth year, as shown below in column B.
Column C shows the value $1 would have grown to earning those annual interest rates. For Year 1 the value is $1(1.05)=$1.05. For year 2 the value is $1.05(1.08)=$1(1.05)(1.08)=$1.134. So $1 at Time 0 is equal to $1.134 at the end of Year 2. Then the amount of money that would have to be invested at Time 0 in order to have $1 at the end of Year 2 is 1/(1.134)=0.8818. In other words, the present value (i.e. value at Time 0) of $1 at the end of Year 2 is $0.8818. This is also called the discount factor for payments received at the end of Year 2.
Part I: Use a spread sheet, such as Excel or Quattro Pro, to make the calculation of present values and discount factors for the following pattern of interest rates.
Consider Table One again. We might ask what was the average interest rate over two years, three years and so on. We want to know what constant interest rate over two years would give the same cumulative value of 1.134. The answer is: the interest rate r such that (1+r) 2 = 1.134.
We can find r by taking the square root of both sides to find that 1+r=1.0649 and so the two year interest rate is 6.49 percent. Note that this is not exactly the arithmetic average of
the interest rates in the first and second years. The average interest rates for the other periods are as follows:
Part II: Construct a corresponding table for the interest rates in Part I.
In Assignment Fifteen we had the interest rates that were expected to
prevail in a number of years in the future and we computed the discount
factors for each of those years. Here we have the discount factors and
want to compute the expected future interest rates (these are often called
the forward rates).
A pure discount bond is one that pays no interest before maturity. At
maturity a pure discount bond pays its face value.
Since the pure discount bond sold at a price below its face value the
payment made at maturity covers the accrued interest. The ratio of the
price of a pure discount bond to its face value is the same as the
discount factor for the period of time until maturity. For example, if
a $1000 face value pure discount bond which has two years to go before
maturity sells for $800, then the discount factor is 0.8. From the
discount factor we could solve for the yield rate r we need to.
If we have the discount factor for three years and for two years we
can find the forward rate for the third year. Since
________1_________ = DF3
(1+r1)(1+r2)(1+r3)
_____1______ = DF2
(1+r1)(1+r2)
the ratio of DF2 to DF3 is equal to (1+r3).
Find the discount factors and from them determine the forward interest
rates for years 1 through 7 from the following data.
Definitions:
A repurchase agreement (usually called a repo) is an
arrangement in which one party sells securities with a committment to
rebuy them at later time. The most common form of such agreeements is
for one day, which is called an overnight repurchase. The interest rate
on these is called the repo rate. It is just slightly above the
T-Bill rate.
A forward interest rate is the interest rate now for a loan over
some period in the future. For example, the interest rate on loans starting
on January 1, 1999 which have to be repaid on December 31, 1999 is the
forward rate for 1999. A company may know that it needs $10 million for
one year starting on January 1, 1999 and want to get a committment on that
loan and its interest rate now. The interest rate it gets would be called
a forward rate.
The duration of a security is the weighted average of the times its
return is paid. The weights are the present values of the payments.
The maturity is the time until the last payment is made.
A pure discount bond is a bond that pays no interest but pays
its face value amount at maturity.
The average interest rate over a period of time is the interest
rate on a pure discount bond that reaches maturity at the end of that period.
For example, the three year interest rate is the interest rate for a pure
discount bond that matures in three years.
The the term structure of interest rates or yield curve is a graph
that shows the relationship between the average interest rate over a period
of time and the period of time to maturity.
Review Problem:
There is five year bond with a face value of $5,000 and a coupon rate
of 6 percent. What are the payments made for this bond?
Year 1 2 3 4 5
Payment ______ ______ _______ _______ _______
Given the following forward interest rates determine the discount
factors for the different years and use them to compute the present value
of the payments made for the above bond.
The same computations can be made using the average interest rates over
different periods. If rT is the average interest rate over T
years then the discount factor for T years is
1/(1+rT)T.
Use the following average interest rates to compute the discount factors
and verify that they are essentially the same as those computed using the
forward rates.
Find the term structure of interest rates; i.e., plot the average
interest rate versus time to maturity.
The previous three assignments dealt with the concepts of forward
interest rates and average interest rates over various periods, such as
a two year rate, a three year rate and so forth. It was shown that you
can get the averages from the forward rates and you can get the implied
forward rates from the averages.
The term structure of interest rates is the relationship between the
interest rate on pure discount bonds and their duration. In other words,
the term structure of interest rates is the relationship between the
interest rates on short term securities and and long term securities.
A swap is a transaction that trades one stream of financial
obligations for another. The most common swap is an interest rate swap,
but foreign currency swaps are also popular, and the market has made
available a wide variety of other swaps. The standard interest rate swap,
commonly known as a plain vanilla swap, is one in which a floating
interest rate obligation is exchanged for a fixed rate obligation. Suppose
a company has a $5 million debt with a five year maturity on which it must
pay an interest rate that is adjusted to the one year T-note rate plus 2
percent. This means the company's interest payment is variable and it is
exposed to an interest rate risk. It may prefer to have a known, fixed
financial payment and so it would seek a swap in which some other party
(called the counterparty) agrees to pay the floating rate payments in
return for receiving a fixed rate payment.
In this assignment you compute the expected present value of the
floating rate payments and compare it to the present value of the fixed
rate payments. The future T-note rates are unknown but the forward rates
are what the market expects the one year rates to be. Assume in the
computation that the T-note rates + 2 percent are the market interest
rates for the risk class of the company's debt, and use these rates to
compute the discount factors.
Expected Present Value of the Floating Rate Obligation
Suppose the swap counterparty wants an 11 percent fixed rate payment.
What is the annual payment? What is the present value of the fixed rate
payments? The fixed rate of 11 percent is a coupon rate and should not be
used for determining the discount factors. Use the discount factors you
computed in the above problem to make this computation. Since the payment
is the same in each year all you have to do to get the present value of the
fixed payments is to multiply the fixed payment times the sum of the
discount factors.
Plain Vanilla Currency Swaps
Suppose Company A in Germany has DM 25 million (Deutsche marks) and Company
B in the U.S. has $10 million. Company A has a need for $10 million for
three years and Company B has a need for 25 million marks for three years.
The current exchange rate is 2.5 DM/$ so they could simply convert their
currency for the one they need. But they both know that after the three
years are up they will want to convert their foreign currency holdings back
to their own currencies. If they simply exchanged their current holding
they would be exposed to an exchange rate risk during their three projects.
They may want a swap in which they trade their current holdings for
foreign currency now and trade them back after three years. During the
three years each party to the swap pays the interest that the other would
be receiving. The interest rate in the U.S. is 10 percent and in Germany
it is 8 percent. The interest rates in both countries are expected to
remain constant over the three year period. The problem is to find out if
the swap is fair to both parties and if not how much one part should pay
the other to make it a fair deal for both.
The first thing to do is to project the exchange rate of marks for
dollars. If the level of risk in Germany is about the same as in the U.S.
and the tax rates are the same then the difference in interest rates
reflects differences in the expected rates of inflation. A 10 percent
rate in the U.S. and an 8 percent rate in Germany indicates that the rate
of inflation in the U.S. is expected to be about 2 percent higher in the
U.S. than Germany. This means the mark will appreciate in value relative
to the dollar. More precisely the rate of change of the exchange rate
is expected to be [(1+0.1)/(1+0.08)-1]=0.0185; i.e., the marks required
to buy one dollar will decline 1.85 percent per year.
The total of the present values comes out to 0.001=$1,000, but this is
due to the rounding that took place during the computation. The exact
answer is 0, indicating that the swap is fair for both parties.
Compute the net value of the swap for Company A in marks.
Compute the net value of the swap another way.
Evaluate a ten year swap of 50 million marks for $20 million when the
interest rates are 12 percent for the U.S. and 10 percent for Germany.
The current exchange rate is 2.5 marks per dollar.
Pineapple Computers has an investment opportunity in Germany. It
requires an initial investment of $800,000 and gives a return in marks as
shown below.
The riskfree interest rate in the U.S. is 6 percent and the rate of
inflation is 3 percent. In Germany the riskfree rate is 9 percent.
Pineapple Computers estimates that the appropriate cost of capital for
this investment, considering the risks, is 10 percent dollar return.
In order to analyze this project you will have to forecast the exchange
rate of marks for dollars. The forward rate exchange rate for one year
gives us the "growth factor" (1+g) for the exchange rate since:
E(SDM/$)/SDM/$ = FDM/$/SDM/$.
If FDM/$/SDM/$ is not known, we can find it
because we know that it is the same as
E(1 which is the same as (1+rL)/(1+r$).
Once we know the growth factor for the exchange rate (1+g) then we
can estimate the exchange rate new year by:
E(SDM/$) = (1+g)SDM/$.
For the second year in the future we apply the same growth factor to
the estimate of the exchange rate next year, and so on to the third, fourth
and beyond years.
Forward Forward
T-note T-note Interest Discount Present
Year Rate + 2% Payment Factor Value
1 5% 7% $350,000 0.93458 $327,102.80
2 8 10 _500,000 0.84962 _424,808.84
3 10 12_ _600,000 0.75859 _455,152.32
4 12 14_ _700,000 0.66543 _465,799.16
5 10 12_ _600,000 0.59413 _356,478.95
Total $2,029,342.07
10.674% af=3.80235
Explanatory Notes for Some of the More Complex Options
Horizontal (Time) Spreads: The simultaneous purchase and sale of the
same type of option (put or call) with the same exercise price but
different expiration dates. Consider the purchase of a 90 day call and
a 120 day call on a stock for which the Black and Scholes method is valid
which is now selling for $100 with an exercise price of $120. The rate of
interest is 12% per year and the standard deviation of the rate of return
is 0.3. The o t variable is (0.3)(.25) = 0.15. The present value of the
exercise price is 120/(1.12)1/4= 116.65 so the ratio of current
price to the PV of the exercise price is 0.86. The Black-Scholes table
gives the value of the call equal to 1.3 percent of the current price or
$1.30 per share. For a call option with a maturity of 120 days the values
for the B&S table are .17 and .87. Interpolating in the table gives a value
for the call option of 2 percent of current price, about $2 per share. If
the second call option is written then the net value of the combination is
($2.00-1.30) or $0.70 per share.
If the current price of the stock is $120 then the ratio of the current
price to the present value of the exercise price for the 90 day option is
0.97 so the value of the call is about 4.65 percent of 120 or $5.58. The
value of the call sold is about 5.65 percent of 120 or $6.78. Thus the
net value of the combination is $1.20.
For a current price of $140 the value of the 90 day call option is
$24.36 whereas the 120 day call has a value of $25.20. The net value of
the combination of buying the 90 day option and selling the 120 day option
is $0.84.
We may also excess the value of the combination as a function of the
price of the stock on the expiration date of the 90 day option. On that
day the call option will have a value of zero for any price at or below
the exercise price. At that time the other option will have 30 days(=0.0833)
years left before expiration. Its value is determined from o t = 0.3
0.0833 =.087 and P/(PVX). At a current price of $100 this ratio is 0.84.
The value is about 1.7 percent of share price; i.e., 17 cents. Since this
is the option that was sold (written) the net value of the combination
is -$0.17.
A swap is a transaction that trades one stream of financial
obligations for another. The most common swap is an interest rate swap,
but foreign currency swaps are also popular, and the market has made
available a wide variety of other swaps. The standard interest rate swap,
commonly known as a plain vanilla swap, is one in which a floating
interest rate obligation is exchanged for a fixed rate obligation. Suppose
a company has a $5 million debt with a five year maturity on which it must
pay an interest rate that is adjusted to the one year T-note rate plus 2
percent. This means the company's interest payment is variable and it is
exposed to an interest rate risk. It may prefer to have a known, fixed
financial payment and so it would seek a swap in which some other party
(called the counterparty) agrees to pay the floating rate payments in
return for receiving a fixed rate payment.
For a current price of $160 the value of the 90 day option is $42.72
and that of the 120 option is about $44.80 so the net value of the
combination is
Modigliani and Miller's proposition that, in the absence of differential
taxes on interest and dividends, the value of a corporation is independent
of its capital structure.
___________________ __________________________
X1 X1
X2
straddle strangle
______________________ __________________________
X1 X2 X1
X2
bull spread bear spread
______________________ __________________________
X1 X2 X3
X1 X2 X3 X4
butterfly spread
condor spread
Assignment Thirteen
A. Buying a call
B. Writing a call
C. Buying a put
D. Writing a put
E. Buying shares
F. Selling short shares
G. Buying a straddle
H. Writing a straddle
I. Buying a bull spread
J. Writing a bull spread
H. Buying a bear spread
I. Writing a bear spread
J. Buying butterfly spread
K. Writing a butterfly spread
L. Buying a condor spread
M. Writing a condor spread
N. Buying a box spread
O. Writing a box spread
Assignment Fourteen
Security Prices, Yields, and Duration
III. Some of the cash payment on a security may come in one year, some in two years, and so on. The duration of a security is the average amount of time the holder has to wait for the payments. The average is a weighted average and the weights are the present value of the payments. For example, for a $1000 three year bond with a coupon interest rate of 10 percent when the market interest rate is 12 percent this is the situation:
Time Payment Disc. Fac. PV PVxTime
1 100 0.8929 89.29 89.29
2 100 0.7972 79.72 159.44
3 1100 0.7118 782.95 2348.87
Totals 951.96 2597.60
Duration = (sum of PVxTime)/(sum of PV) = 2.7289 years
Time Payment Disc. Fac. PV PVxTime
1 100 0.8929 89.29 89.29
2 100 0.7972 79.72 159.44
3 1100 0.7118 782.95 2348.87
Totals 951.96 2597.60
Assignment Fifteen:Trends and Fluctuations in Interest Rates And
the Term Structure of Interest Rates
Table One
A B C D
Interest Cumulative Present
Time Rate Value Value of $1
0 $1.0000 1.0000
1 5% 1.0500 0.9524
2 8% 1.1340 0.8818
3 10% 1.2474 0.8017
4 12% 1.3971 0.7158
5 10% 1.5368 0.6507
Time(yrs) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Interest
Rate 6% 9% 10% 11% 13% 10% 8% 6% 4% 6% 5% 6% 5% 6% 6%
Table Two
A B C D
Interest Cumulative Average
Years Rate Value Rate
1 5% 1.0500 5.00 %
2 8% 1.1340 6.49
3 10% 1.2474 7.65
4 12% 1.3971 8.72
5 10% 1.5368 8.89
Assignment Sixteen
Pure Disc Face Discount Forward
Year Bond Price Value Factor Interest Rate
1 $952.38 $1000 ______ _______
2 $865.80 $1000 ______ _______
3 $773.04 $1000 ______ _______
4 $702.76 $1000 ______ _______
5 $650.70 $1000 ______ _______
6 $608.13 $1000 ______ _______
7 $579.18 $1000 ______ _______
Assignment Seventeen
Forward
Interest Discount Present
Time Rate Factor Payment Value
1 5% ______ _______ _______
2 8% ______ _______ _______
3 10% ______ _______ _______
4 12% ______ _______ _______
5 10% ______ _______ _______
Average
Interest Discount
Maturity Rate Factor
1 5.00% ______
2 6.49 ______
3 7.65 ______
4 8.72 ______
5 8.89 ______
Assignment Eighteen
Forward Forward Expected
T-note T-note Interest Discount Present
Year Rate + 2% Payment Factor Value
1 5% 7% $350,000 0.93458 $327,102.80
2 8 ___ ________ _______ ___________
3 10 ___ ________ _______ ___________
4 12 ___ ________ _______ ___________
5 10 ___ ________ _______ ___________
Total ___________
Present Value of the Fixed Rate Obligation
Assignment Nineteen
Expected Cash Flows for Company A
Expected
Exchange Equivalent Discount Present
Time Dollars Marks Rate Dollars Factor Value
(millions) (millions) (DM/$) ($millions) @10% (mill)
0 10 -25 2.500 0.000 1.000 0.000
1 -1 2 2.455 -0.185 0.909 -0.168
2 -1 2 2.410 -0.170 0.826 -0.140
3 -1-10=-11 2+25=27 2.366 0.412 0.751 0.309
Total 0.001
Assignment Twenty
Equiv $ Present
Cash Flow Forecast Cash Flows Value
Year (000s DM) (000s $) xr DM/$ (000s $) (000s $)
0 0 800 1.60 ______ ______
1 500 0 ____ ______ ______
2 600 0 ____ ______ ______
3 700 0 ____ ______ ______
4 700 0 ____ ______ ______
5 700 0 ____ ______ ______
L)/E(1
$)
Determine the NPV of the project. __________________
Is the investment worthwhile? ___________ What is the Internal Rate of
Return (IRR) of the project? ________
What should the appropriate cost of capital in Germany is be? ____
Compute the NPV in marks. _____________
What is the dollar value of this NPV converted at the current spot rate of
DM/$? _____________ Is the project worthwhile? _________
________________________________________________________________
In the above problem what is the real rate of interest in the U.S.?
_____________
If this is also the real rate of interest in Germany, what is the expected
rate of inflation in Germany? _________
If 10 percent is the risk adjusted cost of capital for Pineapple, what is
the risk premium? ____________
If the same risk premium applies to the cost of capital in Germany and the
riskfree rate is 9 percent, what is the appropriate risk-adjusted cost of
capital for the marks cash flow?__________
Expected Present Value of the Floating Rate Obligation
Swaps