The sharp global stock-market sell-off that began on October 19, 1987, is known as Black Monday.
The Dow Jones Industrial Average dropped 22.6% that day, while major markets in Europe, Asia, and elsewhere also recorded extraordinary losses. Because the fall occurred across interconnected financial centers, the event became one of the first clearly global modern market crashes.
Researchers identify several contributing conditions rather than one definitive trigger. Equity valuations were high, interest rates had risen, and investors worried about economic and trade conditions. Portfolio-insurance strategies and other computer-assisted trading practices could amplify selling once prices began falling.
The crash did not produce the prolonged economic collapse associated with the 1929 Wall Street Crash. Central banks, including the US Federal Reserve under Alan Greenspan, supplied reassurance and liquidity. Exchanges subsequently developed circuit breakers and coordinated procedures intended to slow panic and give participants time to assess rapidly changing prices.
The same nickname is also used for other market shocks, so the year is essential when identifying the 1987 event.