The 1980s U.S. crash associated with the October 1987 collapse was called Black Monday.
Black Monday refers specifically to October 19, 1987, when the Dow Jones Industrial Average fell 22.6 percent. Markets in Hong Kong, Australia, the United Kingdom, and other countries also suffered dramatic losses, making the event a global crash rather than an isolated New York episode.
Several forces were present before the collapse, including high valuations, concerns about interest rates, a widening U.S. trade deficit, and uncertainty about currency markets. Computerized trading strategies may have accelerated the selling, although historians and economists continue to debate the relative importance of each factor.
Black Monday is easily confused with Black Tuesday, the key selling day of the 1929 crash. The two names describe different events: Black Monday was in 1987, while Black Tuesday was in 1929.