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 3rd Friday of the expiration month; however, broker age 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.
EXPIRATION DATE
Meaning of EXPIRATION DATE in English
Campbell R. Harvey. Hypertextual finance English glossary. Английский словарь гипертекстовых финансов. 2012