Often associated with volatility, the final trading hour of the 3rd Friday of March, June, September, and December as contracts for stock index futures, stock index options and stock options all expire at the same time.

Occurs on the third Friday in March, June, September, and December, when the S&P futures contract, S&P index option contract, and options on individual stocks, all expire simultaneously. Triple Witching happens at these particular intervals because these investment instruments can be purchased in 3,6,9, and 12 month durations. On Triple Witching, markets are unusually very active as traders try to close out their positions, long or short, in the option they have or in the underlying stock. Dramatic price swings often occur on Triple Witching and even more so in the final hour of trading.

Quarterly, simultaneous expiration of stock options, stock futures and options on stock indexes. Typically creates tremendous volatility in the stock market for the day as dealers and investors "square" their positions.