The 1987 market crash that began in Hong Kong before spreading rapidly to Europe and the United States was Black Monday.
On October 19, 1987, the Dow Jones Industrial Average fell 22.6%, its largest one-day percentage decline. The sell-off followed sharp drops in Hong Kong and other markets, then moved across time zones to Europe and North America.
Several factors contributed, including high valuations, concerns about interest rates and trade, portfolio insurance strategies, and automated selling. The crash exposed how linked global exchanges had become.
Black Monday is often confused with Black Tuesday, October 29, 1929, one of the major collapse days of the Wall Street Crash of 1929. Despite the similar names, the 1987 crash did not produce a Great Depression-scale economic contraction.