What was the 24 October 1929 US market sell-off commonly called?

The 24 October 1929 US market sell-off is commonly called Black Thursday.

Black Thursday marked the first major panic session of the Wall Street Crash. Trading volume reached a then-record level, and the Dow Jones Industrial Average fell sharply. A group of leading bankers later met at J.P. Morgan & Co. and bought selected shares to support prices, temporarily calming the market.

The relief did not last. Black Monday occurred on 28 October, followed by Black Tuesday on 29 October, when selling intensified and the Dow suffered another major fall. These sessions are often grouped together under the broader name Wall Street Crash of 1929.

Black Thursday did not by itself cause the entire Great Depression. The market collapse interacted with bank failures, debt problems, declining production, unemployment, and contraction in international trade. The date is also sometimes confused with Black Tuesday, the session most closely associated with the crash’s climax. The 1929 episode remains one of the most studied financial crises in modern history.