The 1987 global stock-market crash that began with extreme selling on October 19 was called Black Monday.
On that day, markets plunged across the world, with the Dow Jones Industrial Average falling 22.6%, its largest one-day percentage decline. The selling began in Asia, spread through Europe, and reached the United States during a tightly connected sequence of trading sessions.
Analysts have linked the crash to overvalued shares, trade and interest-rate concerns, and computerized portfolio-insurance strategies that accelerated selling. Unlike the 1929 crash, it did not lead to a Great Depression.
The episode prompted major changes in market infrastructure. U.S. exchanges later adopted circuit breakers designed to pause trading during exceptionally rapid declines, giving investors time to assess new information.