Black Tuesday was the 29 October 1929 crash day associated with record trading volume on the New York Stock Exchange at that time.
On Black Tuesday, the Dow Jones Industrial Average fell 30.57 points, or 11.73 percent. About 16 million shares changed hands, overwhelming the exchange’s systems and dramatically exceeding previous records. The selling followed Black Monday’s collapse, when the Dow had already dropped 12.82 percent.
The crash ended the speculative boom of the 1920s and became the best-known symbol of the Wall Street Crash. Many investors had bought shares on margin, using borrowed money. Once prices fell, brokers demanded more collateral, and forced sales pushed prices still lower.
Black Tuesday is not identical to the entire 1929 crash. Prices had begun declining earlier, and the market continued to fall after October. Nor did the day alone cause the Great Depression: bank failures, reduced production, unemployment, and international economic policies all contributed to the broader crisis.