What nickname was given to the October 1987 worldwide stock-market collapse?

The October 1987 worldwide stock-market collapse was nicknamed Black Monday.

The name usually refers specifically to Monday, October 19, 1987, when markets around the world plunged. Hong Kong fell first, followed by major European exchanges and the United States. The Dow Jones Industrial Average lost 22.6%, its largest one-day percentage decline.

The episode was international rather than limited to New York. Australia, Canada, Hong Kong, the United Kingdom, and other markets recorded severe losses. Researchers have linked the crash to stretched valuations, macroeconomic worries, portfolio insurance, and trading mechanisms that could reinforce selling.

“Black Monday” can also refer to later market declines, including October 27, 1997, and October 19, 1987 remains the best-known usage. It should not be confused with Black Tuesday, the nickname commonly associated with October 29, 1929.