Black Monday was the 1987 market crash that caused major stock exchanges worldwide to suspend or restrict trading.
On October 19, 1987, equity prices collapsed across international markets. The FTSE 100 fell 26.45% that day, while the Dow Jones Industrial Average lost 22.6%. The shock was global: markets in Hong Kong, Australia, and Europe suffered major declines before or alongside Wall Street.
Trading restrictions and temporary closures were used to manage disorderly conditions. After the crash, regulators developed coordinated circuit breakers and other procedures designed to pause trading during extreme price movements. Black Monday is distinct from the 1929 Wall Street crash, even though both events use a weekday-and-color nickname and are often confused in popular summaries.