Quick Answer
American-style options let the holder exercise any time before expiration, while European-style options allow exercise only at expiration. Most equity options are American style, and most index options are European style. The names describe exercise timing, not geography, and the early exercise right means an American-style option is never worth less than a matching European-style one.
Building on the equity vs. index distinction, let's look more closely at the two exercise styles, because when you can exercise an option significantly affects its value and how it's used.
Memory Aid: American = Any time. European = Expiration only.
American Style Options
- Can be exercised any time before or at expiration
- The holder has maximum flexibility
- This flexibility means an American-style option is never worth less than an otherwise identical European-style option, and it usually carries a higher premium
- Most U.S.-listed equity options are American style
- American-style options carry early exercise risk for sellers, which is why they usually command a higher premium (a call on a stock that pays no dividend before expiration is worth the same in either style)
European Style Options
- Can only be exercised at expiration
- The holder cannot exercise early, even if the option is deep in-the-money
- Never worth more than an otherwise identical American-style option, and usually priced lower, because of reduced flexibility
- Most index options are European style
- Both styles can be bought and sold (traded) at any time before expiration; the restriction for European style is only on exercising, not on trading
Exam Tip: Gotchas
- European-style options can still be traded (bought and sold) at any time. The restriction is on exercising, not trading.
- Exercise style and settlement type are separate concepts. American-style equity options use physical delivery; European-style index options use cash settlement. These are independent features that happen to pair together in practice.
Comparison Table
| Feature | American Style | European Style |
|---|---|---|
| Exercise timing | Any time before or at expiration | Only at expiration |
| Common usage | Equity options | Index options |
| Premium | Never lower; usually higher (more flexibility) | Never higher; usually lower (less flexibility) |
| Early exercise risk for sellers | Yes | No |
Exam Tip: Gotchas
- "American" and "European" have nothing to do with geography. An American-style option can trade in Europe, and a European-style option can trade in the U.S. The names refer solely to exercise timing. This misconception is frequently tested.
- Both styles trade on U.S. exchanges. The terms refer to exercise timing, not where the option is listed.
What Should You Check on Exam Day?
- Can you explain the difference between American-style and European-style exercise timing?
- Do you know which option type, equity or index, is usually American style versus European style?
- Can you explain why American-style options carry early exercise risk for sellers and are never worth less than otherwise identical European-style options?
- Do you know that European-style options can still be bought and sold at any time, even though exercise is restricted to expiration?
- Can you explain why "American" and "European" refer to exercise timing, not geography?