A way of exercising specific rights attached to an instrument/ security/ contract or any other set-up which can take place any time prior to expiration, including on expiration date. For example, an American-style option (American option) gives the holder the right, but not the obligation, to buy (American call option) or sell (American put option) an underlying asset at an agreed-upon price on or before the expiration date of the contract, regardless of the prevailing market price of that asset at the time of expiration or exercise.

American-style exercise allows investors to secure profit as soon as the underlying price moves favorably, while taking advantage of dividend payouts as well. Most listed stock options (exchange-traded options) including those on European markets, are American-style.

Other examples of American-style instruments/ securities include American-style bonds.