The 1987 one-day stock-market collapse in which the Dow Jones Industrial Average fell 22.6% was called Black Monday.
On 19 October 1987, the Dow dropped 508 points, equal to 22.6% of its value. Major markets around the world also suffered steep losses, making the event a global crash rather than an isolated American decline. Hong Kong’s market fell first because of time-zone differences, followed by markets in Europe and North America.
Several factors were discussed afterward, including high valuations, rising interest rates, a weakening dollar, trade concerns, and automated portfolio-insurance strategies. No single cause fully explains the scale of the fall. The crash also led regulators to develop circuit breakers, temporary trading halts designed to slow extreme price movements. Black Monday is distinct from the 1929 Wall Street crash, even though both names draw on the traditional association of market disasters with weekdays.