The worldwide stock-market collapse of October 19, 1987, is most commonly called Black Monday.
On that Monday, the Dow Jones Industrial Average fell 508 points, or 22.6%, in a single session. The decline spread rapidly to markets in Europe, Asia, Australia, and elsewhere, making the event a genuinely international crash rather than a problem confined to New York.
Several factors were blamed, including computerized program trading, portfolio-insurance strategies, high valuations, trade tensions, and concerns about the dollar and interest rates. No single cause fully explains the speed and scale of the selling.
Black Monday is often confused with the 1929 crash’s Black Tuesday. The names refer to different events: Black Tuesday occurred on October 29, 1929, while Black Monday occurred on October 19, 1987. The 1987 crash also led regulators to develop circuit breakers and other trading safeguards.