Returns a numerical value, indicating the expiration date of the financial instrument the study is applied to. The date is calculated based on the expiration rule selected in the symbol root and is indicated in the ''YYYMMdd'' format, where YYY is the number of years since 1900, MM is the month, and dd is the day of the month.
For example, the value returned for the date of October 30th, 2008 will be 1081030, and for April 2nd, 1999 will be 990402.