What name is given to the severe U.S. stock-market collapse that began in October 1929?

The severe U.S. stock-market collapse that began in October 1929 was the Wall Street Crash of 1929.

During the 1920s, share prices rose rapidly while many investors bought stocks with borrowed money, a practice known as buying on margin. The market became increasingly vulnerable when economic growth slowed, corporate profits weakened, and investors tried to sell at the same time.

The crash unfolded over several dramatic trading days. October 24 became known as Black Thursday, while October 29 became Black Tuesday. The Dow Jones Industrial Average continued falling after October and eventually lost nearly 89 percent from its 1929 peak to its 1932 low.

The crash did not by itself cause every part of the Great Depression, but it intensified financial stress and damaged confidence. Bank failures, falling prices, unemployment, and reduced international trade followed. The event is broader than any single trading day.