Black Monday identifies the 19 October 1987 global stock-market collapse, when the Dow Jones Industrial Average fell 22.6% in one session.
The decline began in Hong Kong and spread through financial markets in Europe and North America. On the New York Stock Exchange, the Dow lost 508 points, the largest one-day percentage fall in its history. Other major indexes also suffered exceptionally sharp losses.
Program trading, portfolio insurance, market psychology, and international market links were among the factors examined after the crash. Unlike the 1929 crash, Black Monday did not lead to a decade-long depression. Central banks supplied liquidity, and regulators introduced or strengthened circuit breakers designed to pause trading during extreme movements.
Black Monday is sometimes confused with the 28 October 1929 Black Monday, when the Dow fell about 13%. The same nickname therefore refers to major crashes in different years, making the date essential when identifying the 1987 event.