What name is given to the 29 October 1929 trading-day collapse in U.S. stocks?

The 29 October 1929 trading-day collapse in U.S. stocks is known as Black Tuesday.

Black Tuesday followed the heavy selling of Black Thursday, 24 October, and Black Monday, 28 October. On 29 October, about 16 million shares changed hands on the New York Stock Exchange, a record at the time. Prices fell sharply as investors rushed to sell, often using borrowed money.

The crash did not by itself cause the entire Great Depression, but it became its most famous financial symbol. Banking failures, falling consumer demand, deflation, and policy decisions deepened the economic contraction during the following years.

Black Tuesday is sometimes incorrectly used as a name for the entire 1929 Wall Street Crash. More precisely, it identifies the final and most dramatic trading day of that October sequence; the broader crash unfolded over several weeks.