A call (or call option) is a contract that gives the holder the right to buy a stated number of units of the “underlying” asset at a given price (which is called the exercise price or strike prile, here we denote the price by X) from the counterparty (called the writer of the option).In the case of a European option,this right can be exercised on a given maturity date T,while for an American option it can be exercised at any time until the terminal date T.+ G# f" s, S8 o l: w
Depending on the underlying asset on which the option is written, a call can be an option on a stock,a stock market index, a currency, a commodity, a bond, or an interest rate,or even a futures contract or a swap (“swaption”). Currency option is popular.5 A( U, `5 H8 O( x6 c4 R: z$ ^7 f% ~9 R
A call option allows you to obtain only the “nice” part of a forward purchase. Rather than paying X for the foreign currency (as in a forward purchase),you pay no more than X, and possibly less than X |