American-Style Option

American-style option

An option contract that can be exercised at any time between the date of purchase and the expiration date. Most exchange-traded equity options are American style.

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American Option

An option contract that may be exercised at any time on or before the expiration date. For example, if one buys an American call giving him/her the right to buy shares in X expiring on the final Friday in March, the call may be exercised at any time on or before the final Friday in March. The differentiating feature of an American option is the fact that its value varies according to the value of the underlying asset over the life of the contract. This means that a holder may wait for an advantageous price and exercise the option. This contrasts with a European-style option, which may only be exercised on the expiration date.

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American-style option. A listed option that you can exercise at any point between the day you purchase it and its expiration date is called an American-style option. All equity options are American style, no matter where the exchange on which they trade is located.

In contrast, you can exercise European-style options only on the last trading day before the expiration date, not before. Index options listed on various US exchanges may be either American- or European-style options.