TRIPLE WITCHING
Plain English
Imagine three school buses dropping students at the same narrow doorway at the exact same time. Teachers check attendance, kids search for friends, everyone squeezes through at once — chaos for ten minutes, then normal. Triple witching is that doorway for markets: stock-index options, single-stock equity options, and index derivatives all expire on the same Friday (third Friday of March, June, September, December). Hedgers, market makers, and arbitrage desks all rush to close or roll positions simultaneously. The surge creates unusual volume, wider spreads, and last-minute price swings that can change your P&L or assignment risk.
Going deeper
Triple witching occurs on the third Friday of March, June, September, and December when three classes of derivatives expire simultaneously: (1) US stock-index futures (ES, NQ, RTY) — their final settlement price is calculated from the SOQ (Special Opening Quotation) of the underlying index computed from opening prices Friday morning; (2) stock-index options (SPX, NDX, RUT) — European-style, cash-settled at the same SOQ; (3) single-stock equity options — American-style, settle in shares. Because index futures stop trading at 9:30 AM ET for final settlement while equity options trade until 4 PM ET, market makers must manage delta across different closing windows. Institutional investors roll futures positions to the next quarterly contract, creating large volume spikes. Bid-ask spreads on equity options frequently widen in the final hour. ATM positions face elevated gamma risk as small stock moves cause large delta swings near expiration.
Examples
Closing a Short Put Early to Avoid Spread Widening
Wednesday before June witching, AAPL trades at $195. You are short a June 190 put at $0.42 bid / $0.50 ask. Historical data shows this strike widens to $0.20 × $0.75 on witching Fridays after 2:30 PM. You close Wednesday at $0.50 to avoid paying $0.75 two days later.
SPX Overnight Risk Into the SOQ
Thursday 3:55 PM, SPX is at 4,492. You are short one SPX June 4,500 call at $6.20. Since it's European-style, you cannot be assigned tonight. But the SOQ is set from Friday morning's opening prices — if ES gaps up 0.5% overnight, intrinsic value at the SOQ could jump to $22.
Rolling Futures on Triple Witching
You are long two ES September contracts from 4,430. The contract stops trading Friday at 9:30 AM. If you haven't rolled to December by then, the position closes at the final settlement price. You roll Thursday afternoon: sell 2 ES Sep 4,448, buy 2 ES Dec 4,452, paying a 4-point roll cost to maintain your market exposure.