When we point clients to the EIA’s latest forecast for a global oil surplus of roughly 5 MMBbl/d in 2027, the response is often disbelief or skepticism. Given the continued disruption to Gulf production and Strait of Hormuz traffic, how does the agency arrive at a surplus of that magnitude? Whether or not the forecast ultimately proves correct, it reflects a specific set of assumptions. Here is how the EIA gets there.
The July Short-Term Energy Outlook (STEO) shows global inventories drawing by 5.1 MMBbl/d in 2Q26 and another 2.2 MMBbl/d in 3Q26. The balance then swings to a 2.7 MMBbl/d build in 4Q26 before averaging a 5 MMBbl/d surplus in 2027.
What assumptions underpin the EIA's 2027 balance?
The annual supply and demand figures side by side make the imbalance easier to see. Global supply falls to 101.89 MMBbl/d in 2026 before rebounding nearly 8 MMBbl/d to 109.84 MMBbl/d in 2027. Demand recovers by only about 2 MMBbl/d, rising from 102.78 MMBbl/d to 104.81 MMBbl/d. Put differently, supply is projected to increase nearly four times as much as demand in 2027.
The projected surplus begins with the return of OPEC+ barrels that were shut in during 2026. Output falls from 39.35 MMBbl/d in 2025 to 35.30 MMBbl/d in 2026 as Gulf producers shut in barrels, then rebounds to 39.88 MMBbl/d in 2027. That represents a 4.58 MMBbl/d increase from 2026, but only 0.53 MMBbl/d of growth from 2025. OPEC+ production recovery is part of the story, but the larger source of new supply lies outside the group.
The larger source of incremental supply comes from non-OPEC+ producers. As the chart above shows, non-OPEC+ supply rises by 3.36 MMBbl/d between 2026 and 2027. The UAE increases from 3.97 MMBbl/d to 5.05 MMBbl/d after leaving OPEC, while the US, Canada, Brazil, Argentina and Guyana each add production. Other non-OPEC+ producers also add barrels, including Qatar as Hormuz flows normalize. No single country creates the glut. Instead, the projected surplus results from production gains across many countries.
The July STEO was completed on July 1, before hostilities resumed and the MoU collapsed. The next outlook may therefore push back the assumed normalization of Hormuz flows and revise the projected global balances to reflect the renewed geopolitical disruption. Still, the July forecast illustrates what could happen if Gulf production recovers, non-OPEC+ supply continues growing and demand rebounds only modestly. Ultimately, the projected glut hinges on whether supply returns as quickly as the EIA assumes.