OPEC, Its Members and OPEC+
OPEC was founded in Baghdad in 1960 and is based in Vienna. It has 11 members since the UAE left. How it is run, how targets are calculated, OPEC+ and the 2026 Hormuz crisis.
OPEC, the Organization of the Petroleum Exporting Countries, is an intergovernmental body founded in Baghdad on 14 September 1960 to coordinate the oil policies of its members. Its headquarters are in Vienna. Since the United Arab Emirates left on 1 May 2026 it has had 11 members: Algeria, the Republic of the Congo, Equatorial Guinea, Gabon, Iran, Iraq, Kuwait, Libya, Nigeria, Saudi Arabia and Venezuela.[1][2] The wider OPEC+ group, which includes Russia, has set output jointly with it since 2016. OPEC does not fix the oil price. It influences supply through production targets, and the price forms in the market.
Foundation and Structure
The five founders were Iran, Iraq, Kuwait, Saudi Arabia and Venezuela. At the time, crude prices were largely set by the posted prices of the international oil companies, and the founders wanted a common position against them. The secretariat began in Geneva and moved to Vienna on 1 September 1965.[1] Austria hosts the organisation and has never been a member.
The supreme authority is the Conference, where delegations are normally led by oil ministers. It meets at least twice a year. Each member has one vote and decisions generally require unanimity, which means one objection can stop a decision.[1] A Board of Governors and a Secretariat headed by the Secretary General handle day-to-day management. The organisation also publishes the OPEC Reference Basket, a price built from members' export grades.
Membership Record
The list has changed many times, which explains why older references give different member counts. Türkiye has never belonged. Russia, Kazakhstan, Azerbaijan and Mexico are also outside OPEC and take part in decisions through OPEC+.
| Country | Membership | Status |
|---|---|---|
| Iran, Iraq, Kuwait, Saudi Arabia, Venezuela | Since 1960 | Founder |
| Libya | Since 1962 | Member |
| Algeria | Since 1969 | Member |
| Nigeria | Since 1971 | Member |
| Gabon | 1975 to 1995, again since 2016 | Member |
| Equatorial Guinea | Since 2017 | Member |
| Republic of the Congo | Since 2018 | Member |
| Qatar | 1961 to 2019 | Left |
| Indonesia | 1962 to 2009, briefly in 2016 | Suspended |
| Ecuador | 1973 to 1992, 2007 to 2020 | Left |
| Angola | 2007 to 2024 | Left |
| UAE | 1967 to 2026 | Left |
Source: Wikipedia, OPEC entry, and the UAE's 2026 announcement.[1][2]
The reasons for leaving differ. Qatar wanted to concentrate on LNG and Angola left over a quota dispute. The UAE announced on 28 April 2026 that it would quit both OPEC and OPEC+. Its capacity had reached about 5 million barrels a day while its quota sat between 3 and 3.5 million.[2] For a low-cost producer that keeps expanding, a quota means investment that cannot be used. The same disagreement lay behind the July 2021 deadlock, when the UAE demanded a higher reference level.
Production Targets and the Quota Calculation
Production targets are OPEC's main tool. A member's target is its reference production less an agreed percentage. The April 2020 deal shows the arithmetic clearly. The group agreed a cut of 9.7 million barrels a day, roughly 10% of world output, with the reference for Saudi Arabia and Russia set at 11 million barrels a day. A 23% reduction took each of them to about 8.5 million.[1] That is why reference levels are fought over at every negotiation. With the same percentage cut, a higher reference leaves a higher right to produce.
The weight of a cut is judged against demand. OPEC puts world oil demand above 105 million barrels a day in 2025.[3] A change of 1 million barrels a day is therefore about 1% of demand. The share looks small, but demand responds weakly to price in the short term, so a small move in supply can produce a larger move in price. Spare capacity matters for the same reason. The term describes idle output that can be brought on quickly and held for some time. Most of it sits in Saudi Arabia, which makes the kingdom the de facto leader even though the statute says nothing of the kind.
OPEC has no sanction to enforce its targets and members exceed them from time to time. Economics textbooks use it as an example of a cartel, a label the organisation rejects.
OPEC+ and the Declaration of Cooperation
The price slide that began in 2014, driven in part by US shale, pushed OPEC to seek a deal with outside producers. In September 2016, in Algiers, it agreed its first cut since 2008. The Declaration of Cooperation followed in December 2016, bringing in ten countries: Russia, Kazakhstan, Azerbaijan, Bahrain, Brunei, Malaysia, Mexico, Oman, Sudan and South Sudan.[1] The combined reduction came to 1.8 million barrels a day.
The arrangement broke down in March 2020, when Russia and Saudi Arabia could not agree on a further cut during the pandemic. A short price war ended with the April deal. The cuts were unwound in stages through 2021 and 2022, and a new reduction of 2 million barrels a day came in October 2022. Eight countries made extra voluntary cuts in 2023 and began reversing them in April 2025. The UAE's exit reduced that group to seven: Saudi Arabia, Russia, Iraq, Kuwait, Kazakhstan, Algeria and Oman.[4]
At the end of 2025 the group also adopted a method for assessing each country's maximum sustainable capacity, and the 2027 reference levels will rest on it.[5] In its statement of 4 October 2026, the seven held their required production for November at the September level. The same decision had been taken for October, which paused the increases after four consecutive monthly rises.[4]
The 2026 Hormuz Crisis
The Iran war that began on 28 February 2026 and the disruption in the Strait of Hormuz exposed the limit of production targets. OPEC+ announced a 206,000 barrel a day increase for April and 188,000 barrels a day for later months, but with the sea route shut a higher target did not turn into supply. By early July shipping through the strait was recovering only slowly.[5][6] On 1 November 2026 Saudi Arabia, Russia, Iraq, Kuwait, Kazakhstan, Algeria and Oman chose to leave their December targets unchanged. Quotas for 2027 are expected to come up at the OPEC+ meeting on 29 November.[8] The crisis also showed the value of capacity that can reach the open sea by pipeline. The region's place in shipping is covered in Persian Gulf.
The 1973 Crisis and After
OPEC's global reach was most visible in 1973. In October the Gulf producers raised posted prices by 70%, and in December by a further 130%. The embargo against the United States and the Netherlands came from a separate body of Arab exporters, OAPEC. First Oil Shock 1973 gives the full account. Much of the new income went into Western banks and was lent on to other countries, the cycle known as petrodollar recycling. The OPEC Fund for International Development was set up in 1976 to support developing countries.
In the 1980s consumers turned to efficiency and other energy sources while non-OPEC output grew. OPEC began assigning production targets in 1982. After 1985, when Saudi Arabia stopped defending the system alone, official prices collapsed and trade moved to market benchmarks. Oil is priced today through references such as Brent.
Reserves and Production Shares
The organisation weighs more in reserves than in output. OPEC's 2025 bulletin puts world proven crude reserves at 1.567 trillion barrels at the end of 2024, with members holding 1.241 trillion, or 79%.[3] That count includes the UAE. Removing its roughly 113 billion barrels brings the share to about 72%. These figures rest on national declarations and remain disputed, since many members lifted their reserves sharply in the 1980s, when quotas were tied to them.
| 2025 crude output | World share | Without the UAE |
|---|---|---|
| OPEC (about 28 million barrels a day) | 35% | 31% |
| OPEC+ | 46% | 42% |
Source: US Energy Information Administration.[7] The same data show the United States as the largest producer, at 13.6 million barrels a day.
Effect on Marine Fuel
No formula links OPEC decisions to bunker prices. The effect arrives by two routes. The first is the cost of crude. The second is quality. Cuts usually fall on the medium, heavy and sour grades of the Gulf, which feed residual fuel production, so a cut can tighten the supply of high sulphur fuel oil. The spread between distillate and residual fuels can therefore move differently from crude after the same decision. The chain from crude to fuel is described in Petroleum.
Frequently asked questions
What is OPEC?
OPEC, the Organization of the Petroleum Exporting Countries, is an intergovernmental body founded in Baghdad on 14 September 1960 to coordinate the oil policies of its members.
Where is OPEC's headquarters?
In Vienna, Austria. The secretariat began in Geneva and moved on 1 September 1965. Austria hosts the organisation and has never been a member.
What is the difference between OPEC and OPEC+?
OPEC is an organisation with a statute and a secretariat, and it has 11 members. OPEC+ is a looser framework joining those members with partners such as Russia under the 2016 Declaration of Cooperation.
Is Türkiye a member of OPEC?
No, and it never has been. Türkiye is a net oil importer, while OPEC brings exporters together.
Why did the UAE leave OPEC?
The gap between capacity and quota had grown too wide. Capacity was approaching 5 million barrels a day while the quota stayed between 3 and 3.5 million.
Does OPEC set the oil price?
Not directly. It affects supply through targets. The price forms in the market along with demand, inventories and non-OPEC output.
How many countries are in OPEC?
Eleven since 1 May 2026: Algeria, the Republic of the Congo, Equatorial Guinea, Gabon, Iran, Iraq, Kuwait, Libya, Nigeria, Saudi Arabia and Venezuela.
Is Russia in OPEC?
No. Russia is outside OPEC and takes part in output decisions through OPEC+.
Sources
- Wikipedia. OPEC: foundation, structure, membership table, Declaration of Cooperation and the April 2020 deal (secondary source).
- Enerdata. UAE Announces Exit from OPEC Effective 1 May 2026, 2026; Hydrocarbon Engineering. UAE to Leave OPEC, 28 April 2026.
- OPEC. Annual Statistical Bulletin 2025, 2 July 2025; Rigzone. OPEC Report Shows Oil Demand Reached over 105 MMbpd in 2025, May 2026.
- OPEC. Saudi Arabia, Russia, Iraq, Kuwait, Kazakhstan, Algeria, and Oman Reaffirm Commitment to Market Stability, 4 October 2026; Nairametrics. OPEC+ Keeps November Oil Production Unchanged, 5 October 2026.
- Argus. OPEC+ Agrees Mechanism to Set New Production Baselines, November 2025; Pakistan Today (Reuters). OPEC+ Approves Minor Oil Hike, March 2026; IANS. OPEC+ Output Quota Increase, May 2026.
- Brussels Signal. OPEC+ Raises Oil Output for Third Month as Hormuz Shipping Recovers, July 2026.
- US Energy Information Administration. Today in Energy, May and June 2026.
- UA.NEWS (citing Channel NewsAsia and Reuters). OPEC+ Keeps December Output Targets Unchanged, 1 November 2026.
