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The time an option contract lapses.
The date by which an option contract is abandoned and becomes worthless unless it is exercised. In an option contract, the holder has the right, but not the obligation, to buy or sell (depending on the type of option) the underlying asset within a certain period of time. The expiration date is the time at which the holder will lose the right to exercise the option. A European option can only be exercised on the expiration date, while an American option can be exercised at any point prior to the expiration date.
The relinquishment of the rights of an options contract by permitting the contract to terminate on the expiration date. Also called abandonment.