Iran War Flips Global Oil Market From Crisis Shortage to Looming Glut

A Market Turned Upside Down

When the Iran War erupted in late February, the world braced for an oil crisis unlike anything in modern history. Prices spiked, tankers were rerouted, and energy markets went into a tailspin. Now, just months later, the International Energy Agency is warning of the opposite problem: too much oil. The same conflict that triggered the worst supply shock on record has simultaneously destroyed so much demand that the global market could be drowning in crude by next year.

The oil supply shock caused by the Iran War has eroded global demand for crude — but a lasting resolution to the conflict could drive a surge in supply volumes and trigger a major oil overhang next year, the IEA said on Wednesday. It's a remarkable reversal that underscores just how deeply the war has warped the global energy system.

The Numbers Tell a Stark Story

In its latest monthly oil market report, the IEA slashed its 2026 demand outlook to 1.1 million barrels a day year-over-year — a 700,000-barrel-per-day downgrade from last month's estimate, after deliveries plunged by 5 million barrels per day in the second quarter. That is an extraordinary collapse in consumption by any measure.

The drop in demand reflects the combined pressure of elevated fuel prices and shortages of refined products, underscoring how the conflict has moved beyond a straightforward supply shock. The conflict caused the restriction of nearly all traffic through the Strait of Hormuz, leading to what the IEA characterized as the "largest supply disruption in the history of the global oil market," with the head of the agency describing it as the "greatest global energy security challenge in history."

Observed global inventories fell by 143 million barrels in May, accelerating the 74 million barrel draw in April, with inventories shedding about 3.8 million barrels per day since the conflict began in February. The IEA warned that further declines in the coming months "could still take global oil stocks to historic lows before the market balance shifts to surplus towards the end of the year."

Peace Could Trigger a Different Kind of Problem

Supply is expected to surge by around 8 million barrels per day to roughly 110 mb/d, heavily outweighing a modest recovery in global oil demand of 2 million barrels per day to 105.3 million barrels per day in 2027. In plain terms: if peace holds and Gulf oil flows resume, the world could find itself with far more oil than it needs.

The report comes as investors weigh how the agreement between the U.S. and Iran to end the conflict, and a potential reopening of the Strait of Hormuz, will impact energy markets. "If the deal holds, exports and production from the Gulf should see a gradual recovery — not least because Iranian oil exports can fully resume once the U.S. blockade is lifted," the IEA wrote.

However, the IEA warned that a full recovery may not be immediate. "Mines will have to be removed from the main shipping lanes and supply chains will take time to normalize," the agency added. Shipments through the Strait rebounded sharply earlier this month, supported by ship-to-ship transfers in the Gulf of Oman, which helped boost total flows from a May low of 9.6 mb/d to around 12 mb/d.

What Comes Next

Analyst Tamas Varga of PVM Oil Associates noted that despite deep inventory drawdowns, oil prices are now "within spitting distance" of their late February levels. That suggests markets are already pricing in a post-war recovery — perhaps optimistically so. Global supply is now expected to drop by 3.9 mb/d year-on-year in 2026 to 102.4 mb/d, before rebounding strongly to 110.3 mb/d next year.

The IEA's analysis reveals an energy market caught between two extremes. The war hollowed out demand through high prices, flight cancellations, and industrial shutdowns — and now a peace deal threatens to flood a weakened market with supply. As the IEA put it, "Our first look at 2027 balances shows a significant overhang emerging next year." For consumers, lower prices may eventually follow. For oil-producing nations, the road ahead looks considerably bumpier than the crisis itself suggested.