The 1987 global stock-market crash, remembered for its 19 October US trading session, was called Black Monday.
On 19 October 1987, major stock markets around the world fell sharply. The Dow Jones Industrial Average lost 508 points, a decline of about 22.6 percent, then the largest one-day percentage fall in its history. Markets in Hong Kong, Europe, Australia, and elsewhere also suffered severe losses.
Several factors were discussed afterward, including high valuations, rising interest rates, international trade tensions, portfolio insurance, and computerized selling. No single explanation fully accounts for the worldwide speed and scale of the decline. Market authorities later introduced or strengthened circuit breakers and other trading safeguards.
Black Monday is sometimes confused with Black Monday dates in other market crises, including 1929 and 2020. In stock-market history, the unqualified term usually refers to 19 October 1987, while the 1987 crash itself unfolded across several trading days and countries.