The Yom Kippur War helped trigger the oil shock that deepened the 1973–1974 global stock-market crash.
Egypt and Syria attacked Israel on October 6, 1973, beginning the Yom Kippur War. In response to U.S. support for Israel, Arab members of OPEC imposed an oil embargo on the United States and some other countries and reduced production.
Oil prices rose sharply, creating inflation and raising costs for businesses and consumers. The shock arrived alongside weak economic growth, contributing to the period known as stagflation. Equity markets around the world suffered during the extended bear market.
The war was an important catalyst for the oil crisis, but the market decline had additional causes, including inflation, monetary tightening, and the end of the postwar economic expansion. The S&P 500 fell substantially from its January 1973 peak to its October 1974 low.