International Energy Agency countries are obliged to hold stock levels equivalent to at least 90 days of their net imports. Stocks are generally held either by industry or a combination of industry and a public entity, i.e. by the government and/or agency established to fulfil this role. Significant regional differences in stockholdings are evident. In IEA North America, over 65% of all stocks and virtually all public stocks are in the form of crude oil. IEA Europe holds a greater share of oil products, reflecting EU regulations on stockholding. In IEA Pacific, three-quarters of all stocks are in the form of crude oil and in IEA North America the vast majority of publicly held stocks (95%) are also crude oil. The aggregate stock level for IEA countries of 4.2 billion barrels is a significant increase from the mid-1980s, when these barely reached 3.0 billion barrels. The steady growth of aggregate stocks reflects the increase in oil demand and subsequent net imports resulting in larger stockholdings, political decisions by some member countries to increase their public stockholding, as well as increased IEA membership.
The oil stocks that the IEA 29 member countries must maintain not only aid energy security but also save money, according to a study contained in the new publication Energy Supply Security 2014.