The 1987 market crash that began in Hong Kong before spreading worldwide is known as Black Monday.
Hong Kong’s stock market fell sharply on October 19, 1987, after earlier weakness in international markets. The selling moved westward through Asian and European financial centers before reaching the United States. By the end of the global episode, many major stock markets had suffered their largest one-day percentage declines on record.
In the United States, the Dow Jones Industrial Average lost 22.6% on October 19. The crash exposed weaknesses in market coordination and in automated trading strategies, prompting regulators to reconsider how exchanges handled extreme volatility.
The label can be confusing because “Black Monday” has also been applied to other market declines, including the 1929 fall on October 28 and the 2020 market sell-off on March 9. The 1987 date is distinguished by its worldwide, extraordinarily rapid spread.