October 19, 1987, the record one-day fall in the 1987 global stock-market crash, is known as Black Monday.
The Dow Jones Industrial Average plunged 22.6%, its largest one-day percentage decline. Selling spread rapidly across international markets: Hong Kong fell first, followed by Europe and the United States. The fall was especially striking because it occurred without an economic depression comparable to the 1930s.
Analysts have linked the crash to overvalued shares, rising interest rates, trade tensions, and computerized portfolio-insurance strategies that encouraged further selling. Regulators responded with measures including trading halts, later known as circuit breakers. Black Monday is sometimes confused with October 28, 1929, which was also called Black Monday, but the 1987 event is the famous modern usage.