OPEC+'s ability to steer global oil markets has weakened six months into the conflict between Iran, Israel and the U.S., with the cartel's share of world oil output dropping to around 40% in July from more than 48% before the late-February attacks. Analysts attribute part of the decline to the United Arab Emirates' withdrawal from OPEC in May, which accounted for roughly 4 to 5 percentage points of the reduction.
The core group of seven OPEC+ producers—including Saudi Arabia and Russia—now accounts for just a quarter of global output, down from a historical peak of about 50% in the 1970s. The cartel's influence has eroded steadily since then, falling to around 30% by the mid-1980s. Recent geopolitical disruptions, including the effective shutdown of the Strait of Hormuz, have further diminished OPEC+'s control over supply flows, turning the central question from production decisions to physical export capacity.
China, the world's largest oil importer, has reduced purchases by roughly 400 million barrels since the war began compared with the same period last year, according to market data. Analysts at Sparta Commodities describe China as the new "swing demand centre," replacing OPEC+'s traditional role in balancing supply and demand. The shift reflects both reduced Chinese buying and logistical constraints that have limited exports from key OPEC members such as Saudi Arabia, Iraq and Kuwait.
Despite announcing six output increases since March, the core OPEC+ group has largely maintained existing production levels due to blockades and infrastructure disruptions. Brent crude futures were trading near $88.28 per barrel on Thursday, little changed from the prior session.
The erosion of OPEC+'s market influence comes as the cartel faces structural challenges, including the rise of non-OPEC supply and shifting trade patterns. The war's disruption of key shipping routes has compounded these pressures, leaving the cartel with diminished leverage over price-setting mechanisms that once defined its dominance.
