Expiration cycles and exercise style

Two features on the contract spec decide a lot of what happens to you: when the option dies, and whether the holder can use it before then.

Expiration cycles

For decades, listed equity options expired on the third Friday of the month, and each stock belonged to one of three quarterly cycles (Jan/Apr/Jul/Oct, Feb/May/Aug/Nov, Mar/Jun/Sep/Dec) plus the nearest two months. That structure still exists, and the third-Friday contracts are still called the monthlies. They usually carry the deepest open interest.

On top of that:

• Weeklies expire every Friday on most actively traded stocks and ETFs. On the largest index products there are expirations on Monday, Tuesday, Wednesday and Thursday as well, so effectively every trading day. An option expiring today is a 0DTE (zero days to expiration) contract; Module 8 covers what that means in practice.
• Quarterlies expire on the last trading day of a calendar quarter on some index products.
• LEAPS (long-term equity anticipation securities) are simply options with more than about nine months to expiration, listed out to two or three years. They are ordinary options; the name is a marketing label.

The last trading day for a standard equity option is the expiration Friday itself (if Friday is a holiday, the Thursday before). Trading stops at the regular 4:00 pm ET close for most equity options; some ETF and index options trade until 4:15 pm ET. Check the spec, because a fifteen-minute difference can matter on expiration day.

Which expiry to pick

The later the expiration, the more time value you pay for and the slower it decays per day. The trade-off is explored in Module 5, but the mechanical facts are:

American versus European exercise

American-style options can be exercised on any business day up to and including expiration. Almost all US equity and ETF options are American.

European-style options can only be exercised at expiration. Most cash-settled index options (SPX, NDX, RUT and the like) are European.

The practical difference is for sellers. A short American option can be assigned early, any day it is in the money, and the seller has no say in the timing. A short European option cannot; the seller knows exactly when the obligation can be triggered. For buyers, the difference is nearly irrelevant, because exercising early throws away whatever extrinsic value the option still has; selling the option in the market is almost always better than exercising it. The exceptions (deep in-the-money calls before a dividend, deep in-the-money puts when interest rates are high) are covered in Module 7.

What happens at expiration

If you hold an option at the close on expiration day:

• In the money by $0.01 or more: the OCC exercises it automatically. A long call becomes 100 long shares per contract at the strike; a long put becomes 100 short shares per contract. Your account has to be able to carry that stock position over the weekend.
• Out of the money: it expires worthless and disappears from the account.
• Exactly at the strike: nothing happens automatically.

You can submit a "do not exercise" instruction for an in-the-money long option, and you can submit an exercise request for an out-of-the-money one (rarely sensible). Both go through your broker, usually by a cut-off around 5:30 pm ET on expiration day.

A worked case. You own two $50 calls on XYZ expiring today. XYZ closes at $50.30. You forget about them. On Monday morning you own 200 shares bought at $50, which is $10,000 of stock you may not have the cash for. If XYZ opens at $48 because of weekend news, you are down $400 before you have had coffee. The fix is simple: close or make an explicit decision on every expiring option before the close.

Key idea: Expiration is not just a deadline; it is a conversion event. In-the-money options turn into stock positions automatically, so decide what you want before the last bell, not after.

The after-hours problem

Auto-exercise is decided by the 4:00 pm ET closing price, but the exercise cut-off is later. If XYZ closes at $49.90 and then jumps to $51 in after-hours trading on news, a holder of the $50 call can still submit an exercise request and take delivery at $50. A seller of that call, who watched it close out of the money and assumed it was dead, can be assigned. This is rare, but it is a real reason to close short options that are near the strike on expiration day rather than letting them "expire worthless" by assumption.

Try it: Find the exchange's contract specification for one equity option and one cash-settled index option. Write down for each: exercise style, last trading time, settlement type, and multiplier. Keep the notes; you will want them when Module 8 talks about pin risk.

Recap

• Monthlies expire on the third Friday; weeklies add every Friday and, on big index products, every weekday.
• Longer-dated options cost more time value and decay more slowly per day.
• American options can be exercised (and short ones assigned) any business day; European options only at expiration.
• In-the-money options are auto-exercised at expiration and become stock positions; close or decide before the bell.
• After-hours moves on expiration day can trigger exercise on options that closed out of the money.