Strike Price Maturity Premium
$1.36/£ 30 days $0.00081/£
$1.34/£ 30 days $0.00021/£
$1.32/£ 30 days $0.00004/£
$1.36/£ 60 days $0.00333/£
$1.34/£ 60 days $0.00150/£
$1.32/£ 60 days $0.00060/£
Current spot rate (US$/£)$1.4260
Expected endings spot rate in 30 to 60 days (US$/£)$1.3200
Potential investment principal per person (£)£250,000.00
Put options on pounds Put #1 Put #2 Put #3
Strike price (US$/£)$1.36 $1.34 $1.32
Premium (US$/£)$0.0008 $0.0002 $0.0000
Put options on pounds Put #4 Put #5 Put #6
Strike price (US$/£)$1.36 $1.34 $1.32
Premium (US$/£)$0.0033 $0.0015 $0.0006
Issues for Arthur to consider:
1. Because his expectation is for “30 to 60 days” he should confine his choices to the 60 day options to be sure and capture
the timing of the exchange rate change. (We have no explicit idea of why he believes this specific timing.)
2. The choice of which strike price is an interesting debate.
* The lower the strike price (1.34 or 1.32), the cheaper the option price.
* The reason they are cheaper is that, statistically speaking, they are increasingly less likely to end up in the money.
* The choice, given that all the options are relatively “cheap,” is to pick the strike price which will yield the required return.
* The $1.32 strike price is too far ‘down,’ given that Sydney only expects the pound to fall to about $1.32.
Net profit Net profit Net profit
Strike price $1.36000 $1.34000 $1.32000
Less expected spot rate (1.32000) (1.32000) (1.32000)
Less premium (0.00333) (0.00150) (0.00060)
Profit $0.03667 $0.01850 ($0.00060)
How many pounds does Arthur have? £250,000.00 £250,000.00 £250,000.00
What is a pound worth in dollars? $1.4260 $1.4260 $1.4260
So Arthur has how many dollars? $356,500.00 $356,500.00 $356,500.00
What does a put on a pound cost? $0.0033 $0.0015 $0.0006
So Arthur can buy puts on how many pounds? £107,057,057.06 £237,666,666.67 £594,166,666.67
Expected profit, in total (profit rate x notional): $3,925,782.28 $4,396,833.33 -$356,500.00
Problem 7.10 Arthur Doyle at Baker Street
Arthur Doyle is a currency trader for Baker Street, a private investment house in London. Baker Street’s clients are a collection of
wealthy private investors who, with a minimum stake of £250,000 each, wish to speculate on the movement of currencies. The investors
expect annual returns in excess of 25%. Although officed in London, all accounts and expectations are based in U.S. dollars.
Arthur is convinced that the British pound will slide significantly — possibly to $1.3200/£ — in the coming 30 to 60 days. The current
spot rate is $1.4260/£. Arthur wishes to buy a put on pounds which will yield the 25% return expected by his investors. Which of the
following put options would you recommend he purchase. Prove your choice is the preferable combination of strike price, maturity, and
up-front premium expense.