The heavy-selling day of October 24, 1929, was called Black Thursday.
Black Thursday was the first major panic day of the Wall Street Crash. Trading volume surged as prices plunged, and the market's decline alarmed investors across the United States. A group of major bankers bought shares to support prices and temporarily restore confidence.
The intervention did not end the crisis. Selling returned in the following trading sessions, including Black Monday on October 28 and Black Tuesday on October 29. The crash contributed to a wider economic collapse, although historians do not treat it as the sole cause of the Great Depression.
Black Thursday is often confused with Black Tuesday because both dates belong to the same 1929 crash. Black Thursday specifically refers to October 24, the first dramatic day of the panic. Black Tuesday refers to October 29, when the market experienced another devastating sell-off.