On Tuesday, the United Arab Emirates, one of OPEC+'s largest producers, announced it will leave the oil producers' alliance on 1 May.

The UAE's withdrawal from the Organization of the Petroleum Exporting Countries (OPEC) weakens the group's control over global oil markets and potentially risks widening a rift with Gulf neighbor Saudi Arabia, the de facto leader of the crude producers' organization.

But what is OPEC, how does it differ from OPEC+, and how does it affect oil prices?

What are OPEC and OPEC+?

OPEC was founded in 1960 in Baghdad by Iraq, Iran, Kuwait, Venezuela and Saudi Arabia with the aims of coordinating petroleum policies and securing fair and stable prices. By 2026 it included 12 countries, mainly from the Middle East.

The UAE, which joined in 1967, is the fourth nation to leave the group in recent years, and by far the biggest producer. Angola, which joined OPEC in 2007, quit the bloc at the start of 2024, citing disagreements over production levels. Ecuador quit OPEC in 2020 and Qatar in 2019.

The group produced over half of global crude in the 1970s, according to Reuters calculations, before the onset of non-OPEC supply sources such as the North Sea. In later decades, OPEC's share stood at between 30% and 40% but record output growth from rivals such as the United States has steadily eaten into that share.

OPEC in 2016 sought to regain influence by forming an alliance with 10 non-members, including Russia, which it called OPEC+. As a result, its market share increased to around 51.15 million barrels per day (bpd), or nearly 50% of global oil and oil liquids production, in 2025, according to the International Energy Agency.

In March, a month into the Iran war, that share fell to about 44%.

US-Iran war reduces UAE production

Before the start of the US-Iran war at the end of February, the UAE was producing 3.3 million bpd and had capacity to be able to produce as much as 4.5-5.0 million bpd of crude and oil liquids.

Its importance in OPEC in the past was increased because, together with leading OPEC member Saudi Arabia, it had spare capacity that it could add to the market if required.

That has become academic since the unprecedented oil market disruption caused by the effective closure of the Strait of Hormuz since the Iran war.

Gulf OPEC+ crude oil production fell by nearly 8 million barrels per day in March versus February as Saudi Arabia, the UAE, Kuwait and Iraq cut output, according to OPEC.

The cuts were necessary because they were limited in how much they could export, although both have some ability to bypass the Strait of Hormuz. Saudi Arabia has a 7 million bpd pipeline to the Red Sea while the UAE can export 1.5-1.8 million bpd through a pipeline to the port of Fujairah.

OPEC and global oil prices

OPEC+ says it cuts and raises oil production to balance the markets. Its critics say the group manipulates prices, which OPEC denies.

During the 1973 Arab-Israeli War, Arab members of OPEC imposed an embargo against the United States in retaliation for its decision to re-supply the Israeli military, as well as other countries that supported Israel. The embargo banned petroleum exports to those nations.

The oil embargo pressured an already strained US economy that had grown dependent on imported oil. Oil prices jumped, causing high fuel costs for consumers and fuel shortages. The embargo also brought the United States and other countries to the brink of a global recession.

US President Donald Trump has accused the organization of "ripping off the rest of the world" by inflating oil prices. Trump has also linked US military support to the Gulf with oil prices, saying that while the US defends OPEC members, they "exploit this by imposing high oil prices".

However, it was Trump who helped to convince OPEC+ to cut output in 2020 during the COVID pandemic as crude oil prices slumped and US oil producers suffered.

In 2025, OPEC crude exports accounted for about 47% of global crude seaborne exports, according to Kpler. In March, that share shrunk to 34.7%, Kpler data show.

Which countries are OPEC members?

With the UAE leaving, the current members of OPEC are: Saudi Arabia, Kuwait, Iraq, Iran, Algeria, Libya, Nigeria, Congo, Equatorial Guinea, Gabon and Venezuela.

Non-OPEC countries in the global alliance of OPEC+ are represented by Russia, Azerbaijan, Kazakhstan, Bahrain, Brunei, Malaysia, Mexico, Oman, South Sudan, Sudan and Brazil.