What name is given to the 1929 collapse of U.S. share prices that helped usher in the Great Depression?

The 1929 collapse of U.S. share prices is called the Wall Street Crash of 1929.

The crash followed a speculative boom in American equities during the 1920s. Many investors bought shares on margin, borrowing money to increase their exposure. When prices began falling, margin calls forced investors to sell, adding further downward pressure.

The crisis included several famous trading days, including Black Thursday on October 24, Black Monday on October 28, and Black Tuesday on October 29. The New York Stock Exchange was the central venue, although the effects spread internationally.

The crash is closely associated with the Great Depression, but historians generally describe the relationship as complex. Banking failures, reduced investment, falling demand, debt pressures, and policy decisions all contributed to the worldwide economic downturn. The stock-market collapse was a major catalyst and symbol, not the sole cause.