The 1929 Wall Street Crash’s worst single-day percentage fall occurred on October 29, 1929, known as Black Tuesday.
On that day, about 16 million shares changed hands on the New York Stock Exchange, a record at the time. The Dow Jones Industrial Average fell 12.82%, following a 12.34% decline on Black Monday, October 28. The two-day collapse intensified the panic that had begun after the market’s September peak.
The crash did not cause the entire Great Depression by itself. Other factors included banking failures, falling demand, debt problems, protectionist policies, and weakness in international trade. The crash did, however, destroy wealth and damage confidence in the financial system.
Black Tuesday is sometimes confused with Black Thursday, October 24, when heavy selling first made the crisis nationally famous. The market continued falling after October 29, and the Dow eventually lost nearly 89% from its 1929 peak to its 1932 low.