What was the nickname of the severe U.S. stock-market fall on 28 October 1929?

The severe U.S. stock-market fall on 28 October 1929 was nicknamed Black Monday. The Dow Jones Industrial Average dropped 12.8% that day as selling accelerated after weeks of instability.

Black Monday was followed by Black Tuesday on 29 October, when the market suffered another enormous decline on record trading volume. Together, the two sessions became the most famous phase of the Wall Street Crash of 1929. The crash did not by itself cause the entire Great Depression, but it severely damaged confidence and helped worsen economic conditions.

The date is sometimes confused with Black Monday in 1987, which describes a different worldwide crash. The 1929 Black Monday occurred in late October, while the 1987 event occurred on 19 October. The repeated nickname reflects the convention of using “black” days to describe exceptionally destructive market sessions.