Black Tuesday, the climax of the 1929 Wall Street Crash, occurred on October 29, 1929.
On that Tuesday, investors sold roughly 16 million shares on the New York Stock Exchange, overwhelming the market and accelerating the collapse that had begun the previous week. The Dow Jones Industrial Average fell about 12% during the session, following another sharp decline on Black Monday.
The crash ended a period of heavy speculation and margin buying in U.S. stocks. Buying on margin allowed investors to control large positions with borrowed money, so falling prices forced many to sell in order to meet loan demands. That selling intensified the downward spiral.
Black Tuesday did not by itself create the entire Great Depression. The depression had several causes, including banking failures, reduced industrial production, and international economic weakness. The crash is nevertheless remembered as a major turning point and a powerful symbol of the decade's economic breakdown.