Iran War Oil Shock: Tanker Attacks, Insurance and the Fed

A war fought with cheap drones over a twenty-one-mile channel is now setting the terms of monetary policy in Washington and Frankfurt.

Six months after American and Israeli aircraft opened the campaign on February 28th, killing Ayatollah Ali Khamenei, the conflict has settled into a rhythm that markets find harder to price than a decisive outcome would be. Brent crude closed above $88 a barrel on July 31st, a gain of more than a fifth over the month, having traded near $72 in mid-June when a memorandum of understanding promised an end to the fighting.

That memorandum is dead. Washington revoked the licence that had waived sanctions on Iranian crude, reimposed its naval blockade, and the war has begun to pull in states that hoped to sit it out. A drone struck the American-owned floating LNG vessel Energos Winter at Egypt’s Damietta port in late July, igniting a fire that spread to a tanker alongside. Saudi Arabia admitted for the first time that it had joined direct strikes on Iranian-backed militias in Iraq. Kuwaiti air defences intercepted Iranian drones on August 1st.

Iran’s strategy is legible even where its leadership is not. Mojtaba Khamenei, elevated by the Assembly of Experts in March, is judged harder line than his father, and the interval since has been spent rebuilding a theory of victory rather than a military.

Two senior Revolutionary Guard officers told the New York Times on August 1st that the Quds Force used the April ceasefire to hold calls with Hizbullah, Houthi and Iraqi militia commanders, coordinating an expansion designed to raise the war’s cost to President Donald Trump.

Reuters has reported covert IRGC cells established in Iraq for attacks on Gulf states hosting American forces. Abbas Araghchi, the foreign minister, calls the doctrine eye for an eye; Major-General Ali Abdollahi has told Gulf hosts of American bases that they will burn.

The aim is cost imposition. Iran cannot contest the air. It can make a fifth of the world’s seaborne oil expensive to move, with equipment costing a fraction of the defence against it.

Defence Secretary Pete Hegseth put the direct Pentagon bill for the war at $37.5bn before the Senate Appropriations Committee on July 21st, up from $25bn in late April. That figure covers operations and the replenishment of munitions but excludes rebuilding the American bases Iran has damaged; the Pentagon’s internal estimate, reported by NBC News, runs to $80bn-$100bn. The White House is asking Congress for $67bn more.

Attacks on shipping are the war’s most economically consequential feature. On July 7th three vessels were struck within twenty-four hours, the heaviest single day since April according to the International Maritime Organisation. The Qatari LNG carrier Al Rekayyat lost its engine room to a drone and broadcast a mayday off Oman; a Saudi crude tanker was damaged the same night.

On July 31st a projectile disabled the engine room of the Bermuda-flagged Gaslog Shanghai off Limah. The IRGC claims to have disabled two American-escorted tankers attempting the strait. Explosive-laden unmanned surface vessels, the weapon Ukraine industrialised in the Black Sea, are now being used against Gulf tankers.

Traffic tells the story. Roughly 130 vessels transited Hormuz daily before the war; at the low point, two. American countermeasures, including the aerial campaign begun on March 19th and the blockade imposed on April 13th, have restored partial flow without restoring confidence.

Marine war-risk insurance is the cleanest real-time gauge of that confidence, and it is flashing red. Additional war risk premiums for Gulf transits ran at 0.10% to 0.25% of hull value before the war. They reached 7.5% to 10% in mid-March, eased to about 1% by late March, then climbed back to 3% to 10% in July. Here’s the chart that shows it all: