They expire into the next futures contract. Spy options expire into SPY stock. http://www.option911.com
Thanks Do serials trade up to 4:15 est Friday? (expiring into the next futures contract as you said earlier) vs 4:15 Thurs for quarterlies, which would expire into the 9:30 Friday AM print of the future expiring that day?
Yes, Serials expire at 4:15 of that Friday afternoon unlike quarterlies which expire 9:30 Friday morning.