During the Panic of 1907, the New York Stock Exchange fell nearly 50% from its 1906 peak.
The panic followed a period of speculation and tightening credit. A failed attempt to corner the stock of United Copper Company helped expose weaknesses in the banking system, and depositors began withdrawing funds from trust companies. The crisis intensified when the Knickerbocker Trust Company collapsed.
J. Pierpont Morgan coordinated private support for banks and trust companies, helping prevent an even wider breakdown. The episode also strengthened arguments for a central bank, contributing to the creation of the Federal Reserve System in 1913.
The figure describes the broad market decline from the previous high, not a single trading-day loss. The Panic of 1907 is therefore an important example of a major cumulative crash rather than one dramatic day like 1929 or 1987.