Reserves of crude oil that are held by the Paris-based International Energy Agency (IEA), which is an independent agency that is aligned with the Organization for Economic Cooperation and Development, a think-tank and economic development agency for Europe. The stocks of oil remain the property of the European countries that contributed them, along with the United States. The reserves are released during times of supply disruption, such as the Gulf War in 1991. They also can be released at other times.