The U.S. stock-market crash that began on October 19, 1987, after a record 22.6% Dow decline was Black Monday.
The date became famous because the Dow Jones Industrial Average suffered its largest one-day percentage loss in its history. Selling was not confined to the United States: equity markets in Europe, Asia, and other regions also fell sharply during the episode.
Analysts identified several contributing conditions, including high valuations, rising interest rates, trade tensions, and automated trading strategies. No single explanation fully accounts for the speed and breadth of the collapse.
The name can be confusing because 1929 also produced famous “Black” market days. October 24, 1929, was Black Thursday, October 28 was Black Monday, and October 29 was Black Tuesday. The 1987 event is specifically Black Monday because it occurred on a Monday.