Options have expiration dates that differ according to the underlying asset. Stock options expire on the third Friday of the month. Futures options expire on different days depending on the contract. Sometimes, different options classes expire on the same day. These days, depending on the scenario, may be referred to as double-, triple-, or quadruple-witching days.
Quadruple-witching days refers to the scenario when all three classes of options expire (stock, stock index, and stock index futures options) along with single stock futures options.
Quadruple witching days occur on the third Fridays of March, June, September and December.