Which 1929 trading day is called Black Tuesday because of its massive U.S. stock sell-off?

The 1929 trading day called Black Tuesday because of its massive U.S. stock sell-off was 29 October 1929.

On Black Tuesday, about 16 million shares changed hands on the New York Stock Exchange, a record at the time. The Dow Jones Industrial Average fell 12 percent, following major declines on Black Thursday and Black Monday. The selling marked the collapse of the speculative boom that had driven U.S. share prices during the 1920s.

The crash did not by itself create every feature of the Great Depression. Banking failures, falling demand, deflation, debt problems, and policy mistakes helped turn a market collapse into a prolonged worldwide economic disaster. The crash nevertheless destroyed wealth and confidence and became its most recognizable financial symbol.

Black Tuesday is often confused with Black Thursday, 24 October, the first major day of the 1929 breakdown. Both dates matter, but 29 October is the canonical date associated with the dramatic final wave of selling.