Triple Witching Hour occurs four times a year, on the third Friday of March, June, September, and December.

It occurs when the contracts for stock index futures, stock index options and stock options all expire on the same day. It is sometimes referred to as "Freaky Friday".

The final trading hour for that Friday is the hour known as triple witching. In this final hour the markets are quite volatile as traders quickly offset their option/futures order before the closing bell. If you are a long-term investor, triple witching has minimal impact.

Moments of extreme volatility on these days were common in the 1980's, but a series of changes in market structure, changes in the timing of expiration and settlement, and, most importantly, broader dissemination of information have largely diffused this phenomenon.