October 19, 1987, marked the 1987 Black Monday crash, when the Dow suffered its largest percentage drop.
The date was a Monday in New York, but the crisis was already global. Hong Kong’s market fell sharply first, followed by major declines in Europe and other financial centers. By the end of the New York session, the Dow had lost 22.6%, or 508 points, in a record one-day percentage collapse.
The crash was not caused by one universally accepted event. Analysts identified overvaluation, interest-rate concerns, trade imbalances, and automated portfolio-insurance selling as important pressures. Once prices began falling, computer-driven orders could add to the speed and scale of the decline.
Black Monday is sometimes confused with Black Monday dates in other market crises. The 1987 label specifically refers to October 19. Unlike the 1929 crash, the 1987 plunge was followed by a relatively quick economic stabilization, helped in part by central-bank reassurance and market reforms.