There are more than half a billion barrels of oil left unsupplied by OPEC+, raising concerns about the group’s ability to balance the global market.  OPEC+ members produced 2.7 million barrels a day less than their target in May, bringing their compliance rate with the deal to 256%, Bloomberg reported.

Some members are having difficulty delivering the volumes of oil they have promised to the market due to diminished investment and operational concerns.

Spare capacity is only available to the core members in the Persian Gulf, and even their untapped reserves could be dwarfed by the losses brought on by the sanctions imposed on Russia in punishment for its invasion of Ukraine. However, it’s currently unclear exactly how much more supply OPEC+ may provide to the market.

At the G-7 summit on Monday, US President Donald Trump was informed by French President Emmanuel Macron that UAE ruler Sheikh Mohammed bin Zayed had stated that the two major oil exporters in OPEC+ are already pumping nearly as much as they can. Suhail Al Mazrouei, the oil minister of the UAE, responded by stating that the country’s crude output is close to the OPEC+ agreement’s production cap at 3.17 million barrels per day.