What nickname was given to the 1987 stock-market crash because of its date?

The 1987 stock-market crash was nicknamed Black Monday because its most dramatic session occurred on Monday, 19 October 1987. The Dow Jones Industrial Average plunged 508 points, equal to 22.6%.

The crash was international rather than confined to the United States. Large losses appeared in markets including London, Hong Kong, Australia, and Canada. Investors had become concerned about valuation levels, interest rates, trade disputes, and the possibility that automated selling strategies could accelerate declines.

The weekday nickname can cause confusion because other major market disasters also carry “Black” labels. Black Tuesday usually refers to 29 October 1929, the most famous day of the Wall Street Crash, while Black Thursday refers to 24 October 1929. The 1987 name is tied specifically to the calendar date and to the unprecedented percentage fall in the Dow. Trading rules were later revised, including the development of circuit breakers designed to slow panic selling during exceptionally rapid declines.