Strait of Hormuz blockade triggers largest oil supply shock in history

Brent crude hit $108.11 per barrel on 27 April 2026—the highest in 18 months—as the Strait of Hormuz blockade entered its ninth week with shipping traffic still paralysed despite a nominal ceasefire. Just seven vessels crossed the strait in the past 24 hours, a 95% drop from the pre-crisis norm of 140 daily passages, according to Insurance Journal. The chokepoint—normally handling 20-25% of global seaborne oil and 20% of liquefied natural gas—has effectively ceased functioning, creating what the International Energy Agency calls the largest supply disruption in oil market history.

The crisis began 28 February following a US-Israel military campaign against Iran that culminated in the assassination of Supreme Leader Ali Khamenei. Iran immediately closed the strait and attacked commercial vessels; the United States imposed a naval blockade on 13 April after peace talks in Islamabad collapsed. Though Iran declared the waterway “open” on 17 April and a two-week ceasefire was announced 8 April, traffic has not recovered. “The strait is still not open, despite the Iran war ceasefire, because Iran is restricting and conditioning traffic,” Abu Dhabi National Oil Company CEO Sultan Al Jaber told reporters.

Supply shock cascades through energy markets

Global oil supply plummeted 10.1 million barrels per day to 97 million in March, with OPEC+ production falling 9.4 million barrels per day, according to IEA data. Spare production capacity collapsed to a record low of 320,000 barrels per day—eliminating the buffer that typically stabilises prices during disruptions. At least 230 loaded oil tankers remain trapped inside the Persian Gulf, holding roughly 14-15 million barrels, while an estimated 500 million barrels of crude have been removed from markets in the first 50 days of the crisis.

The IEA released a record 400 million barrels from emergency reserves in March, the largest coordinated drawdown in the agency’s history. “The cure is opening up the Strait of Hormuz,” IEA Executive Director Fatih Birol said in an interview with Fortune on 23 April. “We are gaining some time, but I don’t claim that this will be a solution, our stock release.”

Brent prices surged from $65 per barrel in late February to above $126 in early March before settling near current levels as strategic reserve releases provided temporary relief. The US Energy Information Administration projects prices will remain above $100 through the second quarter, with peak forecasts reaching $115 per barrel if the strait remains closed.

Shipping costs explode, insurance markets freeze

Very Large Crude Carrier rates hit an all-time high of $423,736 per day in early March, imposing a $20 per barrel Shipping premium from the Middle East to China, according to CNBC. War-risk insurance premiums surged 200-300%, from 0.02-0.05% of vessel value to 0.5-1%—translating to $600,000-1.2 million per single tanker trip, up from $40,000 before the crisis, per Euronews.

The US Central Command redirected 37 vessels since the blockade began 13 April, forcing oil flows onto longer alternative routes via the Cape of Good Hope or overland pipelines with far lower capacity. Refineries have responded by cutting runs: Middle East and Asia facilities reduced throughput by approximately 6 million barrels per day to 77.2 million in April, compressing margins after an initial spike when middle distillate cracks reached record highs.

Macro spillovers: dollar strength, inflation risks

The crisis triggered a flight to safety that strengthened the US dollar approximately 2.5-3% against the euro and yen in early March, with the DXY index hitting a 2026 high of 99.18 on 8 April. Two-year Inflation breakevens spiked from 2.8% to 3.2% as markets reassessed inflation trajectories following the oil surge, creating tension ahead of the Federal Reserve’s 29 April policy decision.

The energy shock has revived inflation concerns just as central banks believed they had contained post-pandemic price pressures. President Donald Trump has taken a hard line, stating the strait is “sealed up tight, until such time as Iran is able to make a deal,” per CNBC. The stance leaves negotiations at an impasse with no clear timeline for resolution.

Renewable transition accelerates as energy security hedge

The blockade has accelerated the strategic case for energy independence through renewables. Chinese solar exports reached a record 68 gigawatts in March—50% above the previous peak—while global electric vehicle adoption reduced oil consumption by 1.7 million barrels in 2025, according to CNN. Renewables accounted for 85% of new global power capacity in 2025, with solar meeting over a quarter of primary energy demand growth for the first time.

“I expect one of the responses to this crisis will be an acceleration of renewables,” Birol told CNBC in March. “Not only because they are helping to reduce emissions but also, they are a homegrown domestic energy source.” The IEA chief’s comments reflect a broader strategic reassessment: chokepoint vulnerability is now priced as existential risk rather than tail scenario.

What to watch

The immediate catalyst is progress—or lack thereof—in US-Iran negotiations, with Trump administration officials shuttling between Gulf capitals this week. Any breakthrough would need to address mine clearance, liability frameworks for shipping insurers, and Iranian demands for sanctions relief—technical hurdles that could take weeks even if political will exists. The Federal Reserve’s 29 April decision will signal how seriously policymakers view energy-driven inflation persistence versus treating the shock as transitory.

Medium-term, watch for cracks in OPEC+ cohesion as Gulf producers outside the blockade zone capture windfall profits while bearing none of the supply curtailment. Saudi Arabia and the UAE have alternative export routes via the Red Sea, creating incentives to maximise output at current prices. If the blockade extends past June, when strategic reserve buffers thin, expect renewed price spikes and potential demand destruction in price-sensitive Asian economies. The cleanest leading indicator: daily ship counts through the strait, currently stuck at single digits with no recovery trend visible.