What was the name of the U.S. market crash on October 24, 1929?

The U.S. market crash on October 24, 1929, was called Black Thursday.

Black Thursday was the first major day of the Wall Street Crash of 1929. Panic selling produced heavy losses and unusually high trading volume on the New York Stock Exchange. A group of leading bankers tried to restore confidence by purchasing shares, and the market temporarily stabilized after their intervention.

The apparent calm did not last. Black Monday followed on October 28, and Black Tuesday came on October 29. The later day produced the largest volume and one of the steepest percentage losses of the sequence, which is why many people remember it more readily than Black Thursday.

The crash occurred during a period of widespread stock speculation, including purchases made with borrowed money. It contributed to a collapse in confidence, but historians identify several economic and financial causes behind the Great Depression rather than assigning the depression to one trading day alone.