Which Vienna exchange event began the worldwide Panic of 1873?

The Vienna Stock Exchange crash began the worldwide Panic of 1873.

A speculative boom in Austria-Hungary ended abruptly on May 9, 1873, a day remembered as Black Friday in Vienna. Share prices collapsed after years of rapid credit expansion, railway speculation, and optimistic investment. Bank failures and losses among investors damaged confidence across the empire.

The shock spread through interconnected European financial markets and soon reached the United States. In September 1873, the failure of the banking firm Jay Cooke & Company helped trigger a major American panic. The resulting depression was long and international, affecting industrial production, construction, trade, and employment.

The Panic of 1873 is sometimes treated as a purely American event because U.S. banking failures are prominent in many accounts. Its opening stock-market break, however, occurred in Vienna. The crisis also helped end the speculative boom associated with railway finance and contributed to a lengthy period later called the Long Depression.