Which event marked the first day of the 1987 global stock-market crash?

Black Monday marked the first day of the 1987 global stock-market crash.

Black Monday was 19 October 1987, when markets around the world suffered exceptionally large declines. The Hong Kong market fell first in the sequence of major market shocks, and the selling then spread westward through Europe and North America. The Dow Jones Industrial Average dropped 22.6% in the United States.

The crash was not caused by one universally accepted event. Concerns about valuations, interest rates, currency movements and trade imbalances combined with computerized trading and portfolio-insurance strategies. These mechanisms could generate additional selling once prices began to fall.

The date is sometimes confused with Black Tuesday, a name used for other market disasters, including 29 October 1929. In the 1987 episode, Black Monday specifically refers to 19 October and became the standard name for the crash’s opening shock.