1. Expiration for Index and Equity Options is the Saturday immediately following the 3rd Friday of the expiration month (except when Friday is a holiday, then the expiration date brings fwd 1 day to Thursday).
2. American Style Option (usually the case)
– can be exercised at any time prior to expiration, up to the 3rd Friday of the expiration month
3. European Style Option
– last trading day is Thursday
– Although an option can be assigned/ exercised any time, the majority of options are assigned the week of expiration