Which stock exchange crash helped begin the worldwide Panic of 1873?

The Vienna Stock Exchange crash helped begin the worldwide Panic of 1873.

On May 9, 1873, often called Black Friday in Vienna, speculative share prices collapsed on the Vienna Stock Exchange. The decline followed a period of aggressive expansion and speculation in Austria-Hungary, especially in railways, construction, and property.

Financial stress then spread through interconnected European and American markets. In the United States, the failure of the banking firm Jay Cooke & Company in September 1873 helped trigger a banking panic and the closure of the New York Stock Exchange for ten days.

The Panic of 1873 ushered in a long economic downturn sometimes called the Long Depression. It was not a single identical crash everywhere: different countries experienced separate banking failures, market declines, and industrial contractions at different times.