London’s underwriters set the true price for ships in Hormuz as navies posture

Two flags confront the Strait of Hormuz this week. Donald Trump states that American forces control the waterway and floats taking charge of the Omani territory; Tehran maintains that ships must seek its permission to enter, with Al Jazeera covering the dispute on August 20. The contest is for authority over a channel that, in practice, is governed elsewhere.

A tanker may follow the corridor set by Washington or Tehran, but passage depends on coverage from London’s underwriters, whose rate cards are now the true gatekeepers. Their judgment is that Hormuz is closed to anyone unwilling to pay a private toll—a decision made weeks before memoranda were signed.

Rates for hull war-risk cover before the US-Israel war on Iran stood near 0.25 percent of a $100 million vessel’s value, or about $250,000, according to Marsh’s Marcus Baker speaking to S&P Global Platts on July 22. As hostilities spread, cover climbed to 1–3 percent, then surged again to 7.5–10 percent. S&P Global Platts reported that a single crossing now costs $3 to $10 million, with spot cover withdrawn and Chubb and Lloyd’s syndicates assembling a $400 million facility—half hull/liability, half cargo—to preserve capacity, per CruxBrief on August 13.

Oil desks watching Brent price at $92.90, noted by Al Jazeera on August 21, face an anomaly: the war-risk premium hasn’t decayed as crossings resume, breaking the usual pattern where rates drop after hostilities pause. The market isn’t pricing disruption expected to end; it is pricing a toll that will persist. Iran and Washington are still negotiating if Tehran can levy an official fee after the toll-free window of their memorandum expired around August 19–21, CruxBrief reported on August 13. The private toll arrived months before any diplomatic settlement.

Trump pursues headline-friendly control and cheap gasoline, enforcing a blockade of Iranian ports with the world’s largest navy. Al Jazeera detailed that the US fired Hellfire missiles at the Panama-flagged Vela Nova for attempting to dock at an Iranian port on August 20. Tehran asserts administrative rights, enforcing them with missiles against ADNOC tankers—fifteen vessels hit since the war began, one crew member killed and twenty injured, as ADNOC told Al Jazeera on August 20.

Oman insists on being paid or consulted, prompting Trump to threaten bombing a US ally rather than watch Muscat strike a deal with Tehran (Al Jazeera, Aug 20). For Lloyd’s, survival means always pricing for disaster.

Kpler tracked 236 ships through Hormuz between August 1–19: 83 used Iran’s route, 3 chose Oman’s US-backed corridor, 2 took the central channel, and 148—more than sixty percent—went dark or strayed, according to Kpler data cited by Al Jazeera on August 20. Of energy carriers, 112 transited and only two used Oman’s route openly. The world’s strongest navy hasn’t convinced shippers, who prefer risking Tehran’s corridor with their transponders off.

The immediate trigger is the expiration of the memorandum’s window and Trump’s assertion of control. The underlying pressure has precedent: in the 1980s Tanker War, Washington reflagged Kuwaiti tankers, but shipowners still obeyed the prices set in London. The difference now is magnitude—premiums run ten to forty times above baseline, dwarfing the modest multiples of the 1980s.

In the Red Sea since late 2023, Houthi missiles raised war-risk costs, but shippers rerouted around the Cape of Good Hope—a costly detour, but feasible since Suez has alternatives. Hormuz has none. Eagle Intelligence reported on June 30 that a Cape route from Ras Tanura adds 42 days and over a thousand tonnes in extra fuel, with no Gulf pipeline able to substitute the nineteen million barrels moved daily. This means premium alone decides which cargoes move.

The argument fails only if premiums collapse toward baseline within weeks of a signed memorandum or Lloyd’s syndicates start undercutting each other. If that happens, the toll was fear and the case falls apart.

Charterers pay first, then refiners, then consumers. Hapag-Lloyd booked an additional $600 million in Middle East costs in its Q2 results, as CruxBrief reported on August 13. Seafarers pay in risk. Shipowners offer six months’ extra wages to entice crews after two Dynacom tankers were struck and a third abandoned, following a projectile hit, reported by Eagle Intelligence on July 21. Underwriters collect seven-figure premiums per voyage, shadow-fleet operators run dark—Lloyd’s List, via the World Ports Organization, counted thirteen tankers crossing just after Monday, ten from sanctioned fleets, on August 22—and whoever manages the strait’s paperwork profits. When a chokepoint extracts fees, it becomes a business needing managers.

Three oil slicks now spread in the Persian Gulf and Gulf of Oman, with one reaching Iran’s Qeshm Island mangroves as ships collide in a corridor lacking traffic discipline, according to the New York Times on August 21. Beijing opposes American efforts to isolate Iran, but Chinese refiners aren’t able to lift oil their insurers won’t cover, ISW reported on August 21. The next Gulf casualty tally will be written not by naval missile exchanges but by darkened ships sailing in a lane absent formal owners.

Hormuz stopped being free as soon as rate cards rose. Everything else—the memos, the missiles, the flags—is just negotiation over who collects.