PSTAT 170, QUIZ 1 INTRODUCTION TO MATHEMATICAL FINANCE 2022
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PSTAT 170, QUIZ 1
INTRODUCTION TO MATHEMATICAL FINANCE
JANUARY 20, 2022
Problem 1. You have purchased one call option expiring in one year with a strike price of $40. The current price of the underlying is $40, the interest rate is zero, and the premium for the call option is $2.28.
(1) (5 points) Draw the payof and P&L diagrams for the call option at expiration.
(2) (5 points) What is the P&L on the option at expiration if the underlying is $57.50 (i.e. S1 = 57.5)?
Problem 2. You have purchased ten call options expiring in one year with a strike price of $100. Simultaneously you enter a short position on the corresponding under- lying for ten shares. The current price of the underlying is $100. The interest rate is 3% efective for one year. Due to some market data errors, the premium for the call option is zero.
(1) (5 points) What is the P&L for your position after one year?
(2) (5 points) Instead of taking a short position in the underlying for ten shares you have decided to go short on a forward contract for 10 shares expiring in one year. As before, the current price of the underlying is $100. What is the P&L for your position after one year?
Problem 3. The S&R index spot price is $200 and the continuously compounded risk-free rate is T = 5%. You observe a 15-month forward price of $210.
(1) (4 points) What dividend yield is implied by this forward price?
(2) (6 points) Suppose you believe the dividend yield over the next 15 months will be 0.5%. What arbitrage would you undertake? Create a table to show your synthetic forward and how you efect the arbitrage.
Problem 4. The S&P 500 total return index is currently trading at 4, 400. The continuously compounded risk-free rate is T = 0.045. The price of a European call option on the S&P 500 total return index expiring in one year with a strike price
of 4, 400 is 525. You have decided to invest $5,000 in an equity-linked CD maturing in one year that guarantees the return of your original investment plus a certain percentage of any upside gain in the S&P 500 total return index over the year. If the market is arbitrage-free, what percentage of any upside gain in the S&P 500 total return index over the year do you expect to receive? i. e. what is the participation rate?
1. Solution
Problem 1 . (1) The payof from the call option is the function
Payof = (S1 — 40)+
and the proit and loss (P&L) from the long call option investment is the function P&L = (S1 — 40)+ — 2.28
(2) The P&L on the option investment at expiration if the underlying is $57.50 is (57.50 — 40)+ — 2.28 = $15.22.
Problem 2. (1) Today, we will pay $0 for call and earn $1000 cash and put it into bank to earn the interest as
Interest = $1000 * 0.03 = $30
After one year, we will exercise the call if the underlying price is higher than $100 and return it. otherwise we will just buy 10 shares to return.
P&L = 10 * (100 — S1 )+ + 30
(2) Today, we will pay or earn nothing for the call and forward. After one year, we will exercise the call if the underlying price is higher than $100 and give it out. otherwise we will just buy 10 shares for the forward.
P&L = 10 * (100 — S1 )+
And the diference is just the interest.
Problem 3. (1) From the formula F0,T = S0 e(r —6)T, we can derive the following equa-
tion:
6 = T — 1T log(F0,T/S0 )
Note F0,T = 210,S0 = 200,T = 0.05,T = 1512, we can calculate 6 = 1.1%
(2) In this case, the theoretical price is
0,T = S0 e(r —6)T = 211.57 > Ftrue = 210,
which means the market price is under-priced, so we can buy the forward can create a synthetic forward in the table below:
|
0 |
T |
Short sell S0 e —6T stock lend S0 e —6T long forward |
+S0 e —6T -S0 e —6T 0 |
— ST +S0 e(r —6)T ST — F |
So we can make arbitrage at time T with amount 0,T — Ftrue = 1.57.
Problem 4 . You must set aside $5, 000 e —0.045 = $4, 779.99 in a bank account to meet the gauranteed return of your original investment of $5,000.
That leaves $5, 000 — $4, 779.99 = $220.01 for investment to create exposure to the S&P 500 total return index. This amount of $220.01 allows you to purchase 220.01/525 = 0.4191 at the money call options on the S&P 500 total return index (i. e. call options on the S&P 500 total return index with strike price 4,400).
The payof at the end of the year from this investment strategy is
5, 000 + 0.419067 (S1 — 4, 400)+ = 5, 000 [ 1 + 0.41915,000 (S1 — 4, 400)+] = 5, 000 [ 1 + 0.41915,000 4, 400 ( S14,400 — 1)+] = 5, 000 [ 1 + 0.3688 ( S14,400 — 1)+]
Answer = 0.3688 or 36.88%
2022-09-05