The May 1873 Vienna Stock Exchange collapse was commonly called Black Friday and helped trigger the Panic of 1873.
On May 9, 1873, panic selling hit Vienna after a period of speculative investment and rapid expansion. Several financial institutions failed, and confidence weakened across markets connected to European and American capital.
The panic spread internationally, reaching the United States later in 1873. The New York banking firm Jay Cooke & Company failed in September, contributing to a suspension of trading on the New York Stock Exchange. The resulting downturn became a long economic depression in many countries.
Black Friday here refers to the Vienna event, not the later U.S. retail shopping day. It is also separate from the 1869 U.S. gold-market crisis that carried the same nickname.