The 1873 market collapse that helped begin a long international depression was the Panic of 1873.
The panic began in Vienna in May 1873 and reached the United States later that year after the failure of the banking firm Jay Cooke & Company. Jay Cooke had helped finance Northern Pacific Railway bonds, and the railroad boom had encouraged heavy borrowing and speculation.
The crisis caused bank failures, falling investment, and a prolonged economic downturn often called the Long Depression. Its effects were international because financial markets and credit networks had become increasingly connected during the nineteenth century.
The panic is sometimes described as the start of the Long Depression, although historians debate the precise duration and severity of that depression. It was not the same event as the U.S. Panic of 1893, which also involved railroad finance.