Which U.S. market index lost nearly 90% from its 1929 peak during the Great Depression?

The Dow Jones Industrial Average lost nearly 90% from its 1929 peak during the Great Depression.

The Dow reached a pre-crash high of about 381 points in September 1929. It then plunged during October, with especially dramatic sessions on Black Thursday, Black Monday, and Black Tuesday. The index eventually reached a low of about 41 points in July 1932.

The collapse was part of a broader economic catastrophe, not an isolated stock-market event. Bank failures, falling prices, reduced investment, and unemployment deepened the downturn. The crash helped destroy confidence, although historians generally view it as one cause of the Great Depression rather than its sole cause.

The Dow tracks a small group of major U.S. companies, so it is not identical to the entire stock market. The S&P 500 did not yet exist in its modern form, and the NASDAQ was founded decades later. The Dow finally regained its 1929 closing high in 1954.