What Is the Definition of an ‘American-Style’ Option?

An American-style option grants the holder the right, but not the obligation, to exercise the option at any time between the purchase date and the expiration date. This contrasts with European-style options, which can only be exercised on the expiration date.

This flexibility in exercise timing makes American options generally more valuable than their European counterparts, all else being equal. This style is common in stock options and is sometimes used in crypto options markets.