The severe global stock-market crash of October 1987 is commonly called Black Monday.
The name usually refers specifically to Monday, October 19, 1987, when markets around the world fell sharply. In New York, the Dow Jones Industrial Average lost 22.6%, a record one-day percentage decline that remains a standard reference point in market history.
The crash followed a long rise in share prices and occurred amid concerns about interest rates, currency values, trade disputes, and economic growth. Computerized trading and portfolio-insurance programs helped turn selling pressure into a rapid cascade.
The phrase can cause confusion because several other market crises have been called Black Monday. The 1987 event is distinguished by its date and by the worldwide scale of the losses. Trading rules were later changed to improve information flow and permit temporary pauses.