World War I prompted the New York Stock Exchange to close for four months in 1914.
The exchange suspended trading on July 31, 1914, shortly after the conflict began in Europe. Officials feared that heavy selling by foreign investors would drain gold from the United States and destabilize international finance. The closure was an exceptional response to wartime uncertainty and pressure on the global payments system.
Trading in bonds resumed in November, while unrestricted stock trading returned on December 12, 1914. The interruption lasted nearly five months from the initial suspension, although it is often described as a four-month closure in historical summaries.
This event is distinct from a single-day crash such as the 1987 Black Monday. It was a market shutdown connected to the outbreak of a major war. The closure also encouraged the development of alternative trading arrangements, including curb-market activity outside the exchange.