The 1987 market crash began in Hong Kong before spreading through international exchanges and is known as Black Monday. Hong Kong's stock market fell sharply on 19 October 1987, followed by heavy selling in Europe and the United States.
The Dow Jones Industrial Average recorded its largest one-day percentage decline, falling 22.6% on 19 October. Markets in Australia, the United Kingdom and other countries also suffered major losses.
Researchers have discussed several contributing factors, including program trading, portfolio insurance, overvaluation and international market linkages. No single explanation accounts for every feature of the crash.
The name Black Monday is also used for other market events, including 28 October 1929. The 1987 date and the 1929 date therefore need to be distinguished carefully.