What was the nickname of the severe stock-market plunge on October 19, 1987?

The severe stock-market plunge on October 19, 1987, was nicknamed Black Monday.

Black Monday is the standard name for the global stock-market crash that began on October 19, 1987. The date fell on a Monday in the United States, where the Dow Jones Industrial Average dropped 22.6%. Hong Kong's market fell first because of time-zone differences, and losses then spread through Europe and North America.

The event is often remembered alongside Black Monday in 1929, but the two crashes were separated by 58 years and had different economic settings. The 1987 episode was not followed by the prolonged banking collapse and mass unemployment associated with the Great Depression.

Researchers have identified several contributing factors rather than one universally accepted cause. These included stretched valuations, macroeconomic uncertainty, international currency tensions, and computer-driven trading strategies. The crash prompted exchanges and regulators to create coordinated trading halts, commonly known as circuit breakers.