Quad witching
The quarterly third Friday of March, June, September and December, when stock options, index options and index futures expire together.
On the third Friday of March, June, September and December, stock options, stock index options and stock index futures all expire on the same day. That quarterly overlap is called triple witching. The older name quadruple witching also counted single-stock futures, which expired on the same Fridays after their 2002 U.S. launch; U.S. single-stock futures stopped trading when OneChicago closed in 2020, and CME Group listed new ones in July 2026.
Trading volume on witching days is commonly well above a typical session, as traders close or roll expiring futures and options positions.
Illustrative example (hypothetical numbers, not a real trade): a trader holds 2 December index futures and 10 December $150 calls on a stock trading at $155. On the December witching Friday both expire, so the trader either rolls the 2 futures to March or lets them settle, and the 10 calls, $5.00 in the money, are worth $500 each in intrinsic value, all on the same day.