The Insurance War

The Five Locks That Closed the Strait of Hormuz — and Why No Government Can Reopen Them

Insurance markets did not close the Strait — mines, missiles, and fast boats did. What the insurance market did was lock that closure in place, creating a normalization timeline governed by actuarial committees rather than admirals. The distinction matters: military conditions can change in hours, but insurance market conditions change in weeks to months.

The Mechanism Nobody Is Watching

The standard narrative of the Hormuz crisis focuses on Iranian mines, missiles, and fast-attack boats. This is understandable — kinetic threats are visible and dramatic. But the actual mechanism that shut down 20% of global oil transit was neither kinetic nor dramatic. It was a series of insurance exclusion endorsements issued by five Protection & Indemnity clubs between March 2 and March 5, 2026.¹

On March 5, Gard, Skuld, NorthStandard, the London P&I Club, and the American Club all issued exclusion endorsements removing the Persian Gulf and Strait of Hormuz from their war-risk extensions — effectively withdrawing coverage for vessels transiting the region. Within 48 hours, daily transits collapsed from 153 to near-zero.² The world’s most important energy chokepoint was effectively closed — not by a naval blockade, but by an insurance market one.³

Understanding why this happened, why it cannot be easily reversed, and what it means for the duration of the crisis requires examining a system most analysts have never encountered: the interlocking architecture of maritime insurance, crew labor law, flag state regulation, and ship financing.⁴

The Five Locks

A commercial vessel transiting a war zone requires five independent conditions to be met simultaneously. The removal of any single condition makes transit impossible. Think of it as five locks on a door — all must be open for a ship to sail.

Lock 1: Hull & Machinery Insurance

The shipowner insures the vessel itself — hull, engines, propulsion systems — through Hull & Machinery (H&M) policies, typically placed at Lloyd’s or through large commercial insurers. A modern VLCC is worth $80–120 million. War-risk premiums, charged as an additional premium on top of standard H&M coverage, spiked from 0.25% to 1–3% of hull value per seven-day period.⁵ On a $100 million ship, that is $1 million per week — painful but commercially absorbable given that the cargo (2 million barrels at $100/barrel) is worth $200 million.

But availability matters more than price. When underwriters withdraw entirely, there is no premium at which coverage can be purchased. The ship cannot legally operate.

Lock 2: P&I Club Coverage

Protection & Indemnity clubs are mutual associations that cover third-party liabilities: crew death and injury, pollution, collision damage, cargo claims. P&I coverage is not optional — ports will refuse entry to uninsured vessels, and flag states will deregister them. When the five major clubs issued exclusion endorsements removing Gulf coverage, they didn’t just raise costs. They removed the legal authority for ships to operate in the region.¹ Clubs may reinstate coverage at elevated premiums — potentially 5–10% of hull value — even before mine clearance is complete, if kinetic threats diminish. But reinstatement requires committee approval, actuarial review, and a sustained observation period without incident.

Lock 3: Cargo Insurance

Cargo insurance is typically arranged by the charterer or cargo owner — the oil company or trading house that owns the oil on board. Cargo war-risk has its own market and its own cancellation dynamics. Even if a shipowner can find hull coverage, the cargo may be uninsurable — and an oil major will not ship $200 million of crude without coverage.⁶

Lock 4: Crew Consent

This is the lock most people miss. Under the International Bargaining Forum agreement activated in early March 2026, seafarers on IBF-covered vessels have the legal right to refuse to enter the designated Warlike Operations Area. If they refuse, they are entitled to repatriation at the company’s expense plus compensation equal to two months’ basic wages.⁷ For a Filipino able seaman earning $1,500/month, the refusal package ($3,000 plus a flight home) is a rational economic choice against the risk of transiting a mined, missile-threatened waterway. The most experienced officers and engineers — the ones you need for a dangerous transit — are also the ones with the most career options and family obligations. You can insure the ship, but you cannot force the crew to sail it.⁸ Refusal rates vary by contract type and crew nationality; Filipino crews, who comprise the largest single nationality in global shipping, may be more likely to exercise refusal rights than Eastern European crews with fewer employment alternatives.

Lock 5: Financing Covenants

Most commercial vessels are financed with maritime loans. The lending banks — Deutsche Bank Shipping, Citi Maritime, DNB, Nordea — require continuous insurance coverage as a condition of the loan. Loss of war-risk coverage triggers a technical default on the financing agreement. The bank can demand immediate repayment or seize the vessel. Even a shipowner willing to self-insure and absorb the risk cannot do so without the lender’s consent — which the lender will not grant because the lender’s own risk models do not permit exposure to uninsured war-zone transits.

The result is an interlocking system where the failure of any single component — insurance, crew consent, financing — cascades through the entire chain and makes transit impossible. Iran did not need to sink a single ship. It needed only to make the insurance market flinch.

A note on scope: The Five Locks framework describes the constraints facing Western-insured commercial shipping. Chinese-flagged vessels operating under separate insurance and regulatory frameworks continue limited transits — an estimated 20–40% of pre-war volumes — as documented in our companion assessment (No Clean Exit). The Strait is functionally closed to the global commercial fleet — but not hermetically sealed. Additional constraints — including port willingness to accept vessels with Gulf transit exposure and sanctions compliance requirements — may operate independently of the five locks identified here, but fall outside the scope of this framework. A sovereign government could theoretically bypass Locks 1, 3, and 5 simultaneously through full government indemnification — which is the mechanism the DFC program attempts. As the following section explains, the attempt has not succeeded in practice because it addresses only some of the locks.

Why the US Government Cannot Fix This

The Trump administration’s response has been to create a $20 billion reinsurance program through the Development Finance Corporation (DFC), with Chubb as the primary underwriter.⁹¹⁰ This addresses Lock 1 (hull insurance) and partially addresses Lock 3 (cargo). But it does not address Locks 2, 4, or 5:

— P&I clubs are mutual associations governed by their own boards, not by US government directive. The DFC cannot order them to reinstate coverage.

— Crew refusal rights are enshrined in international maritime labor law (MLC 2006) and the IBF framework. The US government cannot override them.

— Financing covenants are private contracts between shipowners and banks. The DFC reinsurance does not satisfy bank risk models because the underlying risk (active combat, mines, missiles) has not changed.

A sovereign indemnification program could theoretically bypass multiple locks simultaneously — this is the mechanism the DFC’s $20 billion reinsurance facility was designed to exploit. Its failure to restart traffic demonstrates that even government-backed solutions cannot override crew consent (Lock 4) or the institutional decision-making processes of mutual P&I clubs (Lock 2). The gap between sovereign intent and commercial behavior is the defining feature of this crisis.

Moreover, the US Navy has privately told tanker executives there is “presently no availability” for escort missions.¹¹ Even in a best case, escorts could move 3–4 ships per day with 7–8 destroyers — against a normal flow of 153 transits daily. The capacity gap is roughly 40:1.

Framework scope: The Five Locks address the commercial and regulatory prerequisites for transit. Physical prerequisites — principally mine clearance — constitute an independent constraint analyzed separately below and in our companion paper on the normalization sequence from ceasefire to commercial transit (The Normalization Sequence).

The Mine Lock

Even if insurance, crews, and financing could be reassembled, the physical mine threat creates an independent barrier. Iran has laid “a few dozen” mines in the Strait as of March 12 and retains 80–90% of its minelaying capability.¹² The US Navy decommissioned its last four dedicated Gulf minesweepers in September 2025¹³ — five months before the war — and now relies on LCS ships with less-proven mine countermeasure packages.¹⁴

Mine clearance is the slowest variable in the normalization sequence. Historical precedents are sobering:

— Suez Canal (1974): Mine clearance operations ran from March 1974 through mid-1975, with British re-search operations extending well beyond the initial US-Egyptian effort. The canal did not fully reopen until June 5, 1975 — 15 months after clearance began.¹⁵

— Kuwait (1991): Sea mine clearance operations took six and a half months after the end of hostilities.

— World War II North Sea: Mines are still being discovered and detonated eighty years later.

Estimated mine clearance costs range from $100–500 million based on historical precedents — though all prior operations occurred without active opposition from the mine-laying state, a condition that cannot be assumed here.

Current clearance operations face an additional complication: they are being conducted during active combat. Iranian fast boats, drones, and anti-ship missiles threaten the minesweeping assets themselves. Multiple sweeps of the same area are required, and you never reach 100% confidence that all mines have been neutralized. The insurance industry understands this — even after a ceasefire, residual mine risk will keep war-risk premiums elevated for years.¹⁶

The mine problem is the physical lock that makes normalization slow even in the best-case diplomatic scenario. You can negotiate a ceasefire in a day. You cannot clear a minefield in a day.

The Perverse Economics of Being Trapped

The crisis has created a counterintuitive economic landscape where some market participants benefit from the closure persisting. Understanding who pays — and who profits — requires examining the charter structures that govern the trapped fleet. Approximately 80 VLCCs with an estimated 160 million barrels of crude worth roughly $16 billion at current prices are currently stranded or rerouted.

Who Pays While the Ships Sit

The global VLCC fleet splits roughly 52% time charter and 48% spot/voyage charter (Clarkson Research, subscription data).¹⁷ But the trapped population skews heavily toward spot — perhaps 55–60% — because spot vessels were more likely to be mid-loading at Iraqi, Kuwaiti, or Saudi Gulf terminals when Hormuz closed. Iraq’s Basra and Khor al-Amaya terminals have been closed due to combat operations as of March 12, removing an additional 2.9 million bbl/day of export capacity. Time-charter operators, typically working for sophisticated oil majors and large traders, were more likely to have paused or diverted before the closure became total.

This split determines who bears the financial burden. On a time charter, the charterer — usually an oil major like Shell or a large commodity trader like Vitol — pays the daily hire rate whether the ship moves or not. That is their contractual risk. The shipowner collects regardless. On a voyage charter, the shipowner bears the delay cost through demurrage provisions, typically $40,000–80,000 per day for a VLCC. But demurrage clauses have time limits and force majeure carve-outs that were never designed for an indefinite closure. We are entering uncharted contractual territory.

The Hedging Trap

Most Gulf crude is priced around the bill of lading date — the moment oil is loaded onto the vessel, not when it is delivered.¹⁸ This means the trapped cargoes were purchased at pre-war levels, roughly $75–85 per barrel. With Brent now trading above $100, cargo owners are sitting on oil that is appreciating daily — a mark-to-market windfall, assuming it eventually gets delivered.

But here is where the economics turn perverse. Refiners and sophisticated buyers routinely hedge their crude purchases by selling futures or buying put options. A refiner who bought a Gulf cargo at $80 and hedged by selling a Brent future at $82 is now facing margin calls on the short futures position as Brent rises above $100 — while the physical cargo that would offset the loss sits trapped behind Hormuz.¹⁹ The hedge and the physical have become disconnected by force majeure. This is a classic basis risk nightmare: the paper position is underwater, the physical position is inaccessible, and the margin calls are immediate. To illustrate: a trader short 5 million barrels faces daily margin calls of approximately $100 million for every $1/barrel rally in Brent — a sum that can trigger liquidity crises even at well-capitalized firms.

Industry reporting suggests several mid-size commodity trading houses are seeking emergency credit facilities to meet these margin calls, though the specific firms have not been publicly identified. The large houses — Vitol, Trafigura, Glencore — have the balance sheets to absorb it. Smaller traders may not. The risk of a forced liquidation cascade, where margin-strained traders dump futures positions into an already dislocated market, is non-trivial.

Winners and Losers

— Cargo owners sitting on oil: A trader who loaded 2 million barrels at $82/barrel (pre-war Brent) now holds cargo worth $200 million at $100/barrel — a $36 million paper gain. The longer the crisis persists and oil prices rise, the more their trapped inventory appreciates. For unhedged or lightly hedged cargo owners, there is no urgency to force ships through the Strait.

— Shipowners on time charter: Vessels on time charter earn the daily hire rate whether moving or stationary. The charterer pays; the shipowner collects. For these owners, being “trapped” is commercially tolerable — even profitable if they have low operating costs.

— Tanker operators on non-Gulf routes: VLCC spot rates hit an all-time high of $423,736/day.²⁰ Ships operating on Atlantic, West African, or US Gulf routes are earning unprecedented returns precisely because Gulf-loading capacity is frozen.

— Hedged refiners: The worst-positioned participants. They cannot deliver the physical oil to offset their hedge, face daily margin calls on short futures, and must choose between crystallizing losses by closing the hedge or funding the margin indefinitely. Their pain is real and compounding.

The parties who want the Strait reopened — refiners, utilities, end consumers, governments facing inflation — are not the ones who control the ships, the insurance, or the cargo. The parties who control those assets are, in many cases, profiting from the status quo.

What This Means

For the Duration of the Crisis

The insurance mechanism means the Strait will not reopen on a military timeline. Even if the US Navy establishes dominance over Iranian surface threats, the five-lock system requires simultaneous restoration of insurance, crew willingness, bank consent, port acceptance, and mine clearance. These operate on different timelines and are controlled by different actors, most of whom are not subject to US government authority.

For Oil Markets

The IEA’s 400-million-barrel reserve release covers approximately 26 days of the Gulf supply shortfall. If the insurance mechanism keeps the Strait closed beyond that window — which the structural analysis strongly suggests — the supply picture deteriorates sharply. The forward curve is flattening toward contango, indicating the market is beginning to price a sustained disruption rather than a short-term spike.

For the Post-War Environment

Marsh projects hull insurance rates will remain 50% above pre-war levels permanently, even after a ceasefire.¹⁶ The mine risk premium will compound this. Gulf shipping economics are being structurally repriced. The Saudi East-West Pipeline and UAE ADCOP bypass pipeline will attract massive new investment. Trade route diversification away from the Gulf — already underway via the Cape of Good Hope — will accelerate.

For Investors

The insurance mechanism is the single most important variable for predicting when oil prices normalize. Watch the P&I clubs, not the Pentagon. The day Gard and Skuld reinstate Gulf coverage is the day the crisis begins to resolve. Everything else — military operations, diplomatic negotiations, mine clearance — is upstream of that signal.

All claims cross-referenced against minimum two independent sources. Estimates presented as ranges where data conflicts.

Originally published March 12, 2026. Updated March 15, 2026.