A foreign currency option is a financial derivative instrument that gives the buyer the right —but not the obligation — to buy (in a ‘call’ option), or to sell (in a ‘put’ option) the contracted currency at a set price or exchange rate (known as the ‘strike price’), on a predetermined expiration date. The seller of the option must fulfill the contract if the buyer so desires. Because the foreign currency option has value, the buyer must pay the seller a premium in exchange for the right to exercise the option. An ‘American’ call or put option can be exercised at any time up to the expiration date; a ‘European’ option can be exercised only at maturity. When hedging regular foreign currency inflows and outflows, forward contracts are more widely used than foreign currency options. However, foreign currency options can be an efficient tool when contingent business events are hedged.