Expiration Date

The expiration date is the last day an option contract exists; after it, the option is either exercised or gone. Standard monthly equity options expire on the third Friday of the month, and liquid names also list weeklies expiring every Friday. Major indexes like SPX now expire every trading day.

Expiration is when the accounting settles. Options that finish $0.01 or more in the money are auto-exercised by the OCC unless the holder opts out; everything else expires worthless. Time value drains toward zero as the date approaches, which is why the same 5%-out-of-the-money call costs far more with 60 days left than with 2.