Which U.S. market index fell 23% in the October 1987 crash, according to the Brady Commission report?

The Dow Jones Industrial Average fell about 23 percent in the October 1987 crash, according to figures associated with the Brady Commission’s review.

On October 19, 1987, the Dow lost 22.6 percent, while other major U.S. indexes also suffered exceptionally large declines. The crash followed a steep rise in share prices and occurred amid concerns about interest rates, currency values, trade imbalances, and market liquidity.

The President’s Task Force on Market Mechanisms, chaired by Nicholas Brady, examined the causes and mechanics of the collapse. Its report highlighted the interaction of computerized trading, portfolio insurance, and fragmented market systems.

The Dow is a price-weighted index of 30 major U.S. companies, so its percentage move is not the same as the performance of every listed stock. The 1987 episode remains notable because the decline was unusually synchronized across global markets.