Glossary term
American Option
An American option is an option contract that can be exercised at any time before or on its expiration date.
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What Is an American Option?
An American option is an option contract that can be exercised at any time before or on its expiration date. This exercise feature distinguishes it from a European option, which can be exercised only at expiration.
Many listed U.S. equity options are American-style. The ability to exercise early can matter for dividends, interest rates, deep in-the-money options, and short-option assignment risk.
Key Takeaways
- American options can be exercised any time up to and including expiration.
- European options can be exercised only at expiration.
- Early exercise is a right, not always the best economic choice.
- Option sellers can face assignment before expiration.
- Exercise style affects pricing, risk management, and trading decisions.
How It Works
A call option gives the holder the right to buy the underlying security at the strike price. A put option gives the holder the right to sell at the strike price. If the option is American-style, the holder can exercise that right before expiration rather than waiting until the last day.
Exercising converts the option into the underlying position or cash settlement depending on the contract. Closing the option in the market is different from exercising it. Often, selling an option can preserve remaining time value better than early exercise.
When Early Exercise Can Matter
Early exercise may be considered when an option is deep in the money, has little remaining time value, or when a dividend affects a call option. Put holders may also consider early exercise when interest and intrinsic value dynamics make immediate exercise attractive.
The point is not that early exercise is common in every case. The point is that the right exists, so both holders and writers must manage the possibility.
Assignment Risk
Option writers have the opposite exposure. If a holder exercises, a short option seller may be assigned. A short call can result in selling shares at the strike price. A short put can result in buying shares at the strike price.
Assignment can happen before expiration for American-style contracts, which can surprise investors who focus only on the expiration date.
American Versus European Options
Exercise style | Exercise timing | Common relevance |
|---|---|---|
American | Any time before or on expiration | Many equity options; early exercise and assignment risk |
European | Only at expiration | Many index options; simpler exercise timing |
The Bottom Line
An American option gives the holder more exercise flexibility than a European option. That flexibility can be valuable, but it also creates early-assignment risk and makes option management more than a simple expiration-date question.