The Expiration is the last day (in the case of American-style) or the only day (in the case of European- style) on which an option may be exercised. For stock options, this date is the Saturday immediately following the 3d Friday of the expiration month; however, brokerage firms may set an earlier deadline for notification of an option holder's intention to exercise. If Friday is a holiday, the last trading day will be the preceding Thursday.