Organization of Petroleum Exporting Countries - OPEC

What Does Organization of Petroleum Exporting Countries - OPEC Mean?
An organization consisting of the world's major oil-exporting nations, OPEC was founded in 1960 to coordinate the petroleum policies of its members and to provide member states with technical and economic aid. OPEC is a cartel that aims to manage the supply of oil in an effort to set the price of oil on the world market, in order to avoid fluctuations that might affect the economies of both producing and purchasing countries.

Investopedia explains Organization of Petroleum Exporting Countries - OPEC
OPEC membership is open to any country that is a substantial exporter of oil and that shares the ideals of the organization. OPEC has 11 member countries, including founder members Iran, Iraq, Kuwait and Venezuela.

OPEC member nations currently supply about 40% of the world's crude oil and 16% of its natural gas. At the end of 2003, OPEC nations possessed about 78% of the world's total proven crude oil reserves.