The 1873 financial panic that followed the collapse of Jay Cooke and Company was called the Panic of 1873.
Jay Cooke and Company was a major U.S. investment bank that helped finance government borrowing during and after the American Civil War. On September 18, 1873, the firm failed after it could not attract enough investors for Northern Pacific Railway bonds. The failure shook confidence in banks and railroads.
The New York Stock Exchange closed temporarily, and a wave of bank failures and business failures followed. Railroad overbuilding, speculative investment, and monetary pressures had already made the financial system vulnerable. The downturn spread internationally, including to Europe.
In the United States, the prolonged economic slump that followed is often called the Long Depression. That label describes the broader depression, while Panic of 1873 identifies the financial crisis that triggered it.