The 1987 global stock-market crash, whose U.S. peak selling day was October 19, was called Black Monday.
On October 19, 1987, major stock markets around the world fell sharply. The Dow Jones Industrial Average dropped 508 points, or 22.6 percent, its largest one-day percentage decline. The fall followed substantial market gains earlier in the decade and was associated with concerns about economic conditions, currency markets, valuation levels, and trading practices.
Computerized program trading and portfolio insurance were widely discussed after the crash. These systems could generate or amplify selling when prices moved lower, although historians and economists do not treat one single cause as a complete explanation. The crash also encouraged exchanges and regulators to develop circuit breakers and other measures intended to slow extreme trading conditions.
Black Monday is sometimes confused with other market days carrying the same nickname. The 1929 crash included Black Thursday, Black Monday, and Black Tuesday, while the 1987 event is specifically identified with Monday, October 19.