Why the US-Iran War Continues to Disrupt Oil Markets

Almost six months into the war between the US-Israel coalition and Iran, global oil markets remain caught in one of the most severe and prolonged supply shocks in modern history. The latest US government estimate, reported by Bloomberg on August 11, projects that oil supply disruptions tied to the conflict will persist at around 600,000 barrels per day through the end of 2027 — a sobering signal that this isn't a crisis nearing resolution, but one settling into a long, grinding stalemate.

How It Started

The war began on February 28, 2026, when the US and Israel launched a joint military operation against Iran that killed Supreme Leader Ali Khamenei and other senior officials. Iran retaliated with missile and drone strikes on US military installations and embassies across the Middle East, including in Jordan, the UAE, and Qatar, and began targeting oil infrastructure and vessels in the Strait of Hormuz — the narrow waterway through which roughly a fifth of the world's oil trade normally passes.

A Historic Supply Shock

The scale of the disruption has been extraordinary by historical standards. The International Energy Agency characterized the early phase of the conflict as the "largest supply disruption in the history of the global oil market," estimating that around 7.5% of worldwide oil supply was affected within the first two weeks. Oil transported through Hormuz collapsed from an average of 21.6 million barrels per day in the last quarter of 2025 to just 4.9 million barrels per day in the second quarter of 2026 — a decline of more than 75%. At various points, the IEA has said more than 14 million barrels per day of global oil supply has been affected by Iran-related disruptions.

Why the Disruption Keeps Persisting

Several overlapping factors explain why this crisis hasn't resolved despite periodic ceasefire attempts and diplomatic pushes. First, Iran has repeatedly attempted to reroute shipping through its own territorial waters rather than established international shipping lanes, and has attacked vessels that don't comply — turning even the strait's partial reopening into a high-risk proposition for commercial shippers and insurers. Second, oilfields and refineries damaged by strikes take significant time to repair; industry analysts have noted that restoring shut-in production can take days, weeks, or months depending on field age and the type of shutdown involved. Third, both sides appear willing to bear substantial economic and military costs rather than concede core demands — Iran wants an end to the US naval blockade, sanctions relief, and war reparations, while the US has pushed for guarantees around Hormuz security and Iran's nuclear program.

A brief ceasefire reached on April 7, 2026, halted major combat operations but never resolved the underlying standoff over the strait, and periodic Iranian attacks against shipping alongside retaliatory US strikes have continued to disrupt traffic for most of the past five months.

The Ripple Effects Beyond Oil Prices

The consequences have extended well beyond crude prices at the pump. The disruption triggered fuel shortages and rationing across parts of Asia that rely heavily on Gulf oil supplies, with countries like Vietnam experiencing panic buying at fuel stations. Concerns have also spread to food security, as fertilizer shortages and rising costs tied to the energy crisis have compounded agricultural pressures in several regions. Global core inflation, while projected to remain broadly stable, has shown significant regional divergence as energy-dependent economies absorb the shock unevenly.

A "War of Endurance"

Analysts increasingly describe the conflict as a war of attrition, where the central question isn't military victory but which side's economy cracks first — Iran's, the broader global market's, or the United States' domestically, given rising political pressure ahead of the November midterm elections. Voters have grown increasingly sensitive to energy costs and skeptical of continued foreign military entanglement, adding a political dimension to how long Washington is willing to sustain the current standoff.

What Would It Take to Fix This?

Congressional analysis suggests the current status quo could persist as long as both the US and Iran assess they can absorb the ongoing economic and military costs of the strait's effective closure. A durable resolution would likely require a verifiable security framework — potentially the Iran-Oman shipping arrangement currently under negotiation — that both guarantees safe passage for commercial vessels and satisfies Iran's core demands around sanctions and the naval blockade. Until then, oil markets are expected to remain highly reactive to every diplomatic headline, tanker attack, and shift in rhetoric from Washington or Tehran.

For ongoing analysis of the conflict's economic impact, see the Congressional Research Service's report on the Strait of Hormuz.

With Washington's own estimates now projecting disruptions lasting into 2027, the message from US officials is increasingly clear: this is no longer a short-term shock markets simply need to ride out, but a structural feature of the global energy landscape that traders, governments, and consumers will likely be navigating for a long time to come.