War Risk Premiums: How the Insurance Market Prices Hormuz
Before a single missile is fired, before a mine is laid, before a naval vessel changes course, the insurance market registers the threat. War risk premiums on tankers transiting the Persian Gulf are among the most sensitive geopolitical indicators available. They move faster than official statements, faster than military repositioning, and faster than most news coverage. The underwriters at Lloyd’s of London are not strategists, but their pricing reflects a continuous aggregation of threat intelligence that rivals most government assessments.
The mechanics are straightforward. Shipowners purchasing war risk insurance pay a base rate that reflects normal operating conditions. When political or military conditions deteriorate in a designated war risk zone — and the Persian Gulf, along with the wider Arabian Sea corridor, qualifies — additional premiums are assessed per voyage or per period. These additional premiums can multiply the baseline cost several times over during acute crises. During the peak of tanker attacks in 2019, some operators reported war risk additions running to seven figures per voyage for large crude carriers transiting toward the strait.
What the premium pricing captures that headline analysis often misses is the layered nature of the risk. The direct risk of a vessel being struck is one component. The consequential risk — that a struck vessel blocks the fairway, closes the port, or triggers a broader military escalation that shuts the entire corridor — is another, and it is priced separately. Underwriters have learned from the tanker wars of the 1980s that the secondary effects of a single successful attack frequently exceed the primary damage. A VLCC on fire in the main shipping channel is not just one ship. It is a potential blockage of a lane that 17 million barrels of oil per day depends on.
The geographic granularity of war risk pricing reveals how the market understands the threat topology. Premiums are higher for vessels calling at Iranian terminals than for those transiting toward UAE or Omani ports. They are higher for slower tankers, which present easier targeting solutions. They are higher for vessels lacking AIS transponders — which creates a perverse incentive, since ships running dark to avoid detection also become more expensive to insure when detected. The market has internalized the operational logic of the IRGCN.
Club coverage — the mutual insurance arrangements through which most major shipping companies cover their liability exposure — adds another dimension. P&I clubs can invoke war exclusion clauses that leave shipowners uncovered for losses in designated zones, effectively pricing some operators out of the route entirely regardless of what war risk underwriters are willing to charge. During the worst periods of the tanker attacks, some clubs provided coverage only with explicit governmental backing from flag states, connecting the insurance market directly to diplomatic and military posture.
The political consequences of premium spikes are underappreciated. When war risk additions become large enough, they appear in the delivered cost of oil in importing nations. Refiners in Japan, South Korea, and India — all of which depend on Gulf crude for a substantial portion of their throughput — track these costs closely. A sustained premium elevation of even a fraction of a percent on a multi-billion-dollar crude import bill becomes a macroeconomic issue. It also creates domestic political pressure that governments cannot ignore, which is why Iranian officials understand that premium manipulation — not through actual attacks, but through credible threat posture — is itself a form of economic leverage.
The strait is a chokepoint in the physical sense. The insurance market is where its chokepoint status is continuously priced and repriced by people with money at stake. Those prices deserve more attention than they typically receive.