Which day saw the Dow Jones Industrial Average lose 12.8% on October 28, 1929?

Black Monday was the day the Dow Jones Industrial Average lost 12.8% on October 28, 1929.

The collapse came after a sharp decline on Black Thursday, October 24, when heavy selling overwhelmed the New York Stock Exchange. Prices briefly recovered, but selling intensified again on October 28 and continued on Black Tuesday, October 29. The Dow fell another 11.7% on Black Tuesday.

The two late-October sessions are often grouped together when people discuss the Wall Street Crash of 1929. The crash did not happen in one moment, however: the market had been weakening after its September 1929 peak, and the decline continued for years. The Dow ultimately reached its low in July 1932, about 89% below its 1929 high.

A common mix-up is calling October 29 Black Monday. October 29 is Black Tuesday; October 28 is Black Monday. Both dates were among the most severe sessions in the crash.