The 1987 stock-market crash that saw the Dow Jones Industrial Average fall 22.6% in one day was Black Monday.
It occurred on 19 October 1987 and remains the largest one-day percentage decline in the Dow’s history. The sell-off was global: markets in Asia, Europe and North America dropped sharply within a short period. The decline followed a powerful five-year bull market and growing concern about valuations, interest rates and international trade.
Many accounts also point to computerized portfolio-insurance strategies and program trading, which could amplify selling once prices began falling. The crash was not caused by one universally accepted event, however. Black Monday is often confused with the 1929 Wall Street Crash, but the two happened nearly six decades apart. Regulators later introduced circuit breakers and other safeguards intended to slow extreme intraday declines.