In F&O market parlance, ‘expiry date’ or simple ‘expiry’ means the last day that an options or futures contract is valid. Once an options or futures contract passes its expiration date, the contract is invalid

When an investor buys an option, the contract gives them the right but not the obligation to buy or sell an asset at a predetermined price, called a strike price, within a given time period, which is on the expiry date. If the investor chooses not to exercise that right, the option expires and becomes worthless and the investor loses the money paid to buy the option.

A futures contract expires on a pre-specified date i.e. the expiry date of the contract. On expiry, futures can be settled by delivery of the underlying asset or cash. In India, only cash settlement is permitted.

The expiration date for all listed stock options in the India States is the last Thursday of the contract month, which is the month when the contract expires. However, when that Friday falls on a holiday, the expiration date is on the Wednesday immediately preceding the last Thursday.

Expiry date of F&O contracts for the month of April 2013 falls on Thursday, 25^th April 2013.