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

The catastrophic U.S. stock-market collapse that began in October 1929 is commonly called the Wall Street Crash of 1929.

The crash followed a long period of heavily speculative buying, particularly in shares purchased with borrowed money. Stock prices reached a peak in September 1929, then began falling as confidence weakened and investors rushed to sell. The most famous sessions were Black Thursday on October 24, Black Monday on October 28, and Black Tuesday on October 29.

The crash did not single-handedly cause the Great Depression, but it severely damaged banks, businesses, and household wealth. Falling share prices reduced investment and spending, while bank failures and credit contraction made the downturn much worse. Economic conditions also varied significantly between countries.

A common mix-up is treating the crash and the Great Depression as identical events. The crash was a financial shock; the depression was the prolonged worldwide economic crisis that followed. U.S. share prices did not return to their pre-crash peak until 1954.