Black Monday was the day in 1987 that saw the largest one-day percentage fall in the Dow Jones Industrial Average.
Black Monday occurred on October 19, 1987. The Dow fell 22.6%, a record one-day percentage decline that has not been surpassed. Unlike the 1929 crash, the 1987 event unfolded in a highly computerized market and spread rapidly across international exchanges.
Several factors were involved, including elevated valuations, worries about economic conditions, trade disputes, and portfolio-insurance strategies that automatically sold futures as prices declined. The precise interaction among these forces remains an important subject in financial-market history.
The crash led exchanges and regulators to strengthen market safeguards. Circuit breakers became a lasting feature of trading infrastructure, intended to provide time for information and liquidity to return during extreme moves.