Which U.S. stock index lost almost 90% of its value from its 1929 peak to its 1932 low?

The Dow Jones Industrial Average lost almost 90% of its value between its 1929 peak and 1932 low.

The Dow reached a record closing level of 381.17 on 3 September 1929. After the Wall Street Crash began in October, it continued falling during the early years of the Great Depression and reached 41.22 on 8 July 1932. That represented a decline of about 89.2% from the peak.

The crash itself is commonly associated with Black Thursday on 24 October, Black Monday on 28 October, and Black Tuesday on 29 October. Those dramatic sessions were part of a longer collapse rather than the entire bear market.

A common mistake is to say the Dow recovered quickly after 1929. It did not return to its 1929 closing high until November 1954, more than 25 years later.