To close a strait, one pictures mines, fast patrol boats, warships. In February 2026, one of the vital arteries of world trade emptied to four-fifths of its traffic without any permanent physical blockade being put in place. The weapon was not a cannon, but a line in a contract: the insurance premium. Made prohibitive, it was enough to immobilize the ships. Welcome to war by premium.
1 A blockade without a blockade
Closing a vital route without firing a single shot.
The paradox
The strait that empties itself
The Strait of Hormuz is one of the most strategic passages on the planet: about 20% of the world's oil, nearly 20 million barrels a day, transits through it, with very few overland alternatives. A conventional blockade would require mining the strait, sinking or boarding ships — a costly and enduring military commitment. In February-March 2026, however, traffic collapsed by more than 80% without any such force being maintained. The mechanism was of a different order: a surge in insurance premiums that made passage economically impossible. A blockade, without a blockade.
2 No insurance, no ship
The mechanism: a cargo ship does not sail without triple cover.
The lock
Making insurance impossible means closing the route
A merchant ship cannot put to sea without insurance. It needs three covers: hull and machinery, civil liability (the so-called "P&I clubs"), and, in a contested zone, an additional war-risk premium (AWRP). Without these three elements, the chain seizes up: ports refuse entry, banks will not finance the cargo, charterers will not sign. The system is binary: an insured ship sails, an uninsured ship stays at the quay. There is therefore no need to sink a vessel to stop it: it is enough to make its insurance unobtainable, or too dear for the voyage to be profitable. Insurance is the true lock of the strait.
3 Hormuz, February 2026
The triggering event, dated and factual.
The spark
Strikes, then the flight of ships
On 28 February 2026, coordinated strikes by the United States and Israel targeted Iran. In retaliation, Iran struck bases and ships in the Gulf and announced the closure of the strait, targeting several commercial vessels. The insurance market's reaction was immediate. The additional war-risk premium, which hovered around 0.125% to 0.25% of the hull value, jumped to 2.5%, up to 5% for the most exposed ships, and higher still in extreme cases — a multiplication by five to sixty depending on the vessel and the date. For some tankers, the premium alone on a single voyage exceeded the freight it earned: the transit became a losing proposition. Ships stopped passing through.
Collapse in transits
> 80%
drop in traffic within a few days (February-March 2026).
War-risk premium
×5 to ×60
from 0.125-0.25% to 2.5-5% of hull value, or more.
4 The committee that draws the forbidden zones
A private body that, without being a state, acts like one.
The Joint War Committee
A private designation with the effect of a state decision
At the heart of the mechanism sits the "Joint War Committee" of the Lloyd's market in London, which publishes the list of high-risk areas. On 3 March 2026, it extended that list to the whole of the Gulf. This committee is not a government body; its decisions rest on underwriting judgment, not on foreign policy. Yet one of its designations has the operational effect of an exclusion zone imposed by a state. An important point: the insurance clubs did not withdraw their cover; they repriced it to extreme levels — on the order of $30,000 a week for a guarantee that previously cost $25,000 a year. As the trade press put it, shipowners did not lose access to insurance, but access to affordable insurance, which amounts to the same thing.
5 The weapon that needs no enforcer
The decisive property: it requires no continuous force.
Self-execution
The system imposes the closure on itself
A naval blockade must be held day and night: the moment the fleet withdraws, the route reopens. The insurance weapon, by contrast, requires no continuous military action after the initial strikes. Once the risk is declared, each link in the chain reacts according to its own interests: reinsurers raise their rates, clubs adjust their terms, the committee lists the zone, shipowners abstain, charterers turn away. As one analyst puts it, "the adversary does not have to enforce the closure: the system imposes it on itself." It is a self-executing weapon, at near-zero military cost: a finite kinetic investment produces an open-ended, self-sustaining disruption.
6 Insurance, an early sensor of risk
The counterintuitive angle: premiums see war coming.
The early signal
The insurance market prices conflict before the exchanges
War-risk premiums are not only a weapon: they are also a sensor. They readjust faster, and sometimes more finely, than oil prices, stock indices or sovereign-debt spreads. At Hormuz, they had already risen by about 60% above their 2024 level by mid-2025, months before the strikes. The precedent is instructive: the Lloyd's committee had classed part of the Black Sea as a high-risk area on 15 February 2022, nine days before the invasion of Ukraine. In both cases, the insurance market "priced" the conflict before it broke out. The underwriter's ledger is a real-time thermometer of geopolitical risk.
7 Insurance, the bottleneck of globalization
A control point of trade, already an instrument of sanction.
The chokepoint
Whoever controls insurance controls who may sail
Insurance is not merely a weapon of crisis: it is a permanent chokepoint of world trade. The oil price cap on Russian crude, decided by the G7, is enforced not by naval force but through access to Western insurance and reinsurance, dominated by London and the P&I clubs: no cover if the barrel is sold above the cap. Russia's response illustrates the limit of this lever: a "shadow fleet" of several hundred tankers has formed, one that self-insures or turns to alternative insurers. The principle remains: whoever holds insurance — London, the clubs, the reinsurers — holds, in effect, who may put to sea. An invisible strait, doubling the straits of geography.
8 The hidden counterpart
The mirror of gold: here the risk is not destroyed, only displaced.
Where the risk goes
A weapon that does not destroy the danger, it relocates it
All insurance is a promise: the promise of a third party to pay if the worst occurs. The hidden counterpart of the insurance weapon is that the risk it drives off is never destroyed: it is displaced, towards less visible bearers. Towards a parallel and opaque market, first: the shadow fleet sails barely insured; should one of its tankers sink, the oil spill is covered by no one — it is the environment and the coastal states that pay. Towards the state, next: when private insurers flee, public authority becomes the insurer of last resort — a US facility offered up to $40 billion of guarantee for Hormuz, and a London-led facility reinsured Ukrainian grain — and it is the taxpayer who, in silence, underwrites the risk. Towards the consumer, finally: the surcharge ends up in the price of oil and of everything that sails. War by premium claims no visible victim, but it carries a bill, a very real one.
The symmetry with gold
The parallel is striking with
the gold central banks are accumulating. Gold is prized because it has
no counterparty — no one can default on it. Insurance, by contrast, is a
pure counterparty — a promise to pay. To turn it into a weapon is to reverse that promise. But in both cases the same law operates: risk is not abolished, it shifts to wherever it is least seen.
9 The weapon's limits
Let us be rigorous: a surcharge, however enormous, is not a closure.
The counterpoint
Trade reroutes, it does not stop
The insurance weapon has real limits. Premiums eventually come back down as the market adapts and factors in protective arrangements. Trade reroutes, but does not dry up: despite the price cap, Russian oil exports fell only slightly, rerouted by the shadow fleet. Often, ships pass anyway, at a surcharge: during the Tanker War of the 1980s, despite more than four hundred vessels hit, less than 2% of Gulf traffic was actually interrupted. Finally, the "weapon" is ambiguous: the Lloyd's committee is not a government, and the scale of the Hormuz closure "exceeded what any party intended or controlled." It is as much a spontaneous reaction of a risk-averse market as a deliberate strategy — an effect an actor can trigger, but not fully steer.
10 War by premium
The most powerful chokepoint is not geographic.
The lesson
The underwriter's ledger, a new theatre of operations
We thought the world's bottlenecks were geographic: a strait, a canal, a pass. The most powerful turns out to be accounting: a line in an insurance policy. Closing Hormuz did not require sinking a ship, only making its insurance impossible. In a networked economy, the underwriter's ledger has become a theatre of operations — a place where one can, at near-zero military cost, halt the trade of an entire region. The hidden counterpart remains: the risk thus driven off has not vanished; it waits, displaced onto the environment, the taxpayer, the consumer. War by premium makes no noise; that is perhaps what makes it so effective.
The compass
①
The blockade by premium. A ship does not sail without insurance; making the war-risk surcharge prohibitive closes a route without a warship. At Hormuz, after the February 2026 strikes, transits fell by more than 80%.
②
A self-executing weapon and a sensor. The system imposes the closure on itself; and premiums "price" conflict before the markets (Black Sea, nine days before the 2022 invasion).
③
The hidden counterpart. The risk is not destroyed, only displaced: towards the shadow fleet and the environment, the state and the taxpayer, the consumer. This sheet sheds light on a debate; it does not constitute investment advice.
Read alongside: The reserve no government can freeze (the other face of the financial weapon) and The obscure metal (the chokepoint). Reference: abbreviations & acronyms (P&I, AWRP, LNG).