Which U.S. stock-market crash began after the speculative boom that peaked in September 1929?

The Wall Street Crash of 1929 began after the speculative boom that peaked in September 1929.

The Dow Jones Industrial Average reached a record closing high on September 3, 1929. After weeks of weakening prices, heavy selling intensified in late October, producing Black Thursday, Black Monday and Black Tuesday.

The crash is closely associated with the start of the Great Depression, but historians generally describe the Depression as the result of multiple interacting forces. Bank failures, reduced spending, debt, deflation and weaknesses in international finance all contributed to the severity and length of the downturn.

The crash was not the first U.S. financial panic and was not confined to one trading session. The Dow continued falling for years and reached its bear-market low in July 1932. That longer decline is why the 1929 event is best understood as a prolonged market collapse rather than a single day.