Black Monday describes the 1987 worldwide stock-market crash that began with the U.S. market’s dramatic fall.
The term usually refers to October 19, 1987, when the Dow Jones Industrial Average dropped 22.6%. Markets in Europe, Asia, Australia, and elsewhere also experienced severe declines, making the episode a genuinely international crash rather than an isolated New York event. The exact size and timing of losses varied by market and time zone.
Several explanations have been proposed, including elevated valuations, concerns about interest rates and exchange rates, portfolio-insurance strategies, and rapidly growing computer-assisted trading. No single cause explains every market’s movement. Afterward, exchanges and regulators developed circuit breakers and other procedures intended to slow trading during extreme volatility.
Black Monday is a reusable label, so the year matters. October 19, 1987, is the famous global crash date; later market declines have also been called Black Monday. It should not be confused with Black Tuesday, October 29, 1929, a key day in the earlier Wall Street Crash.