Vienna’s stock exchange suffered a major collapse at the start of the Panic of 1873.
The crisis began with the Vienna Stock Exchange crash on 9 May 1873, a day known in German-speaking financial history as Gründerkrach. A speculative boom had encouraged heavy investment in companies, property, and railway projects. When confidence broke, prices plunged and many ventures failed.
Financial stress then spread through Germany and to the United States, where the failure of the investment firm Jay Cooke & Company contributed to a banking panic in September 1873. The resulting depression lasted for years in many countries and is often described as the Long Depression.
Vienna is the specific answer for the opening exchange collapse. The later U.S. panic is an important connected event, but it did not begin the international crisis.