Quadruplewitching: A phenomenon that happens four times a year, when stock index futures, stock index options, stock options, and single-stock futures all expire on the same day. During these expiration days, the markets can be highly volatile, with some stocks rising or falling dramatically. This volatility is often attributed to the impact of institutional investors such as hedge funds making large investments or divestments to offset their derivatives positions. Despite the potential for risk, savvy traders can take advantage of Quadruplewitching to make profits.