The Panic of 1873 was the stock-market crash associated with the collapse of the Vienna Stock Exchange boom and the start of the Long Depression.
The Vienna market crashed on May 9, 1873, a date remembered in German-speaking Europe as Black Friday. The panic followed intense speculation in property and railway companies, especially during the expansion that accompanied the early-1870s boom. When confidence broke, prices fell sharply and financial failures spread.
The shock reached other markets, including Germany and the United States. In the United States, the failure of the banking firm Jay Cooke & Company in September 1873 helped trigger a major panic and the closure of the New York Stock Exchange for several days. The resulting downturn is often called the Long Depression, although its severity and duration varied by country.
The term can cause confusion because “Black Friday” is also used for later market crises and for a retail shopping day. In the 1873 context, it refers specifically to the Vienna crash of May 9.