Stocks could face another explosion of volatility Friday as $4 trillion of options expire in ‘quadruple witching’

Stocks have been on a wild ride this week, and conditions could still get weirder as traders brace for “quadruple witching” on Friday, when a flurry of equity options and futures contracts expire.

In particular, options contracts tied to $4 trillion in stocks, stock-index futures and exchange-traded funds are set to expire, making Friday potentially the busiest day for options traders this year, according to data compiled by Rocky Fishman, the head of index volatility research at Goldman Sachs.

The…