Which U.S. stock index lost nearly 90% of its value during the Great Depression crash?

The Dow Jones Industrial Average lost nearly 90% of its value from its 1929 peak to its 1932 low.

The Dow reached a record high in September 1929 before the Wall Street Crash and subsequent economic contraction. It did not reach its pre-crash closing high again until 1954, roughly a quarter-century later.

The decline reflected more than one dramatic trading day. Banking failures, reduced industrial production, falling prices, unemployment, and shrinking demand reinforced one another during the Great Depression.

The Dow is a price-weighted index of selected major U.S. companies, so its performance is not identical to that of every American share. The S&P 500 did not yet exist in its modern form during the 1929 crash, another reason the Dow is the standard index for this historical comparison.