Some index options â DAX, Stoxx, FTSE â which do not trade on the quarterly cycle have expiration dates which do not correspond to an underlying future/future expiration date. Quarterly options and futures are December options/December future, March options/March future, June options/June futures. But what is the underlying for the remainder, eg January and February options? Iâve been calculating a future fair value for the underlying with the expiration date equal to the option expiration date. Now Iâm having doubts as to whether this is correct. Advice greatly appreciated. Grant.