What event is widely viewed as the immediate trigger of the 1907 U.S. financial panic?

The Knickerbocker Trust collapse is widely viewed as the immediate trigger of the 1907 U.S. financial panic. On October 22, 1907, depositors withdrew funds from the New York institution after its president, Charles T. Barney, was linked to an unsuccessful attempt to corner United Copper stock.

The failed speculation damaged confidence in trust companies, which were important financial intermediaries but held less cash than traditional commercial banks. A run on Knickerbocker Trust quickly spread concern through New York's banking system, while stock prices fell and credit became difficult to obtain.

Banker J. P. Morgan organized private support for threatened institutions and helped coordinate a response. The panic exposed the absence of a U.S. central bank able to provide emergency liquidity. It contributed to the creation of the Federal Reserve System in 1913.