The 1873 financial panic that began with a Vienna stock-market collapse was the Panic of 1873.
On 9 May 1873, the Vienna Stock Exchange crashed in an event remembered in German-speaking Europe as Black Friday. The shock followed years of speculative investment, especially in railways, property, and construction. Confidence weakened, and financial failures spread beyond Austria-Hungary.
The panic became part of a broader international depression often called the Long Depression. Bank failures and falling investment affected Germany, the United States, Britain, and other economies. In the United States, the failure of the banking firm Jay Cooke & Company in September 1873 helped trigger a major Wall Street crisis and a long suspension of stock trading.
The name can cause confusion because “Black Friday” has also been used for later market events and retail shopping. In this historical context, it refers specifically to the Vienna crash of 9 May 1873, not to a modern shopping date.