The Dow Jones Industrial Average declined approximately 89% from its 1929 peak to its 1932 trough.
The Dow reached a closing high of 381.17 on September 3, 1929, before the market began a prolonged collapse. It ultimately fell to 41.22 on July 8, 1932. That peak-to-trough decline was close to 89 percent, making the episode one of the deepest major-market collapses in modern financial history.
The sharp losses reflected more than one day of panic. The market had been supported by speculation, margin borrowing, and confidence that prices would continue rising. As prices fell, leveraged investors faced margin calls and were forced to sell, creating additional downward pressure. Bank failures, deflation, unemployment, and contracting production deepened the wider economic disaster.
The Dow did not recover its 1929 closing high until November 1954. A common mistake is to use the roughly 12 percent fall on Black Tuesday as the total crash; the 89 percent figure measures the entire peak-to-trough decline through 1932.