OPEC’s 1973 embargo contributed to the global stock-market downturn.
Several Arab members of the Organization of the Petroleum Exporting Countries imposed an oil embargo in October 1973 against countries viewed as supporting Israel during the Yom Kippur War. Oil prices rose sharply, creating inflation, energy shortages, and economic stress in importing countries.
The resulting crisis contributed to a broader period of stagflation and falling equity markets. In the United States, the bear market that began in 1973 continued into 1974, while inflation and recession weakened corporate profits and investor confidence. The oil shock was an important cause, but not the only one; monetary conditions and pre-existing economic imbalances also mattered.
OPEC itself was founded in 1960, well before the embargo. The embargo was imposed by Arab members, so “OPEC” identifies the organization associated with the event rather than claiming every member took identical action.