Black Monday, when the Dow Jones Industrial Average fell a record 22.6% in 1987, occurred on October 19, 1987.
The Dow dropped 508 points, its largest one-day percentage decline in its history. Selling spread rapidly through international markets: Hong Kong fell first, followed by European exchanges and Wall Street. The crash was especially striking because it happened without a banking collapse or a prolonged economic depression immediately beforehand.
Several factors contributed, including high share valuations, rising interest rates, a widening trade deficit, and computerized portfolio-insurance programs that automatically sold futures as prices declined. Those automated strategies may have intensified the downward spiral, although historians and regulators identify multiple causes rather than one simple trigger.
The crash is often confused with the 1929 Wall Street Crash because both are associated with a Monday or Tuesday panic. Unlike 1929, however, the United States entered neither a Great Depression nor a long-term collapse after 1987, and the market eventually recovered.