Which U.S. stock index lost nearly 90% of its value during the Wall Street Crash?

The Dow Jones Industrial Average lost nearly 90% of its value during the Wall Street Crash of 1929 and the subsequent bear market.

The Dow had reached a peak in September 1929 after years of rapid speculation and rising share prices. Selling intensified in October, with Black Thursday on October 24, Black Monday on October 28, and Black Tuesday on October 29 becoming the crash’s best-known sessions. The index continued falling after those dates and did not reach its ultimate low until July 1932.

The crash itself was not the sole cause of the Great Depression. Banking failures, falling demand, debt problems, deflation, and policy decisions deepened the economic collapse. Nevertheless, the market decline destroyed wealth and damaged confidence in businesses and financial institutions.

The Dow is a price-weighted index of selected major U.S. companies. Because its composition and calculation differ from broader indexes, claims about the 1929 crash should not be transferred automatically to the S&P 500 or other benchmarks.