LONDON, May 5, 2026 — The Strait of Hormuz, through which roughly a fifth of the world's seaborne oil supply transits annually, has remained a persistently elevated war-risk zone for tanker operators since Iran's acceleration of vessel seizure and harassment operations from 2019 onward, with hull war-risk breach premiums for Hormuz transits trending at elevated but contained levels in current conditions — below Red Sea peaks but structurally non-trivial for high-value VLCC and Suezmax cargoes.
Iranian Seizure and Harassment Incidents
Iran's Islamic Revolutionary Guard Corps Navy (IRGCN) has conducted a sustained campaign of vessel seizures, attempted boardings, and navigational harassment in and around the Strait of Hormuz, the Gulf of Oman, and the broader Persian Gulf. The pattern escalated markedly from 2019 and has continued with varying intensity since.
Documented incidents include the seizure of the British-flagged Stena Impero in July 2019; the seizure of the MV Advantage Sweet, a Marshall Islands-flagged tanker, in April 2023; and the temporary seizure of the Marshall Islands-flagged Niovi in the same period. Iranian forces have also targeted vessels linked to Israeli interests in the region in response to the broader Middle East conflict that escalated from October 2023.
The IRGCN has employed a combination of fast-attack craft, helicopter insertions, and legal pretexts (typically citing maritime law violations or vessel links to sanctioned entities) to justify seizures. Once detained, vessels have been held for periods ranging from days to months, creating not only physical loss exposure but extended loss-of-hire claims and crew welfare incidents.
US Navy and IMSC Presence
The International Maritime Security Construct (IMSC), a US-led coalition providing maritime security escorts and surveillance in the Gulf region, has maintained a presence in Hormuz approaches since 2019 under Operation Sentinel. The coalition includes vessels and maritime patrol aircraft from the US, UK, Australia, Bahrain, and several other nations.
The IMSC presence has provided some deterrence against the most overt seizure attempts but has not eliminated IRGCN harassment operations, which often occur in international waters outside the practical response window of coalition assets. The US Fifth Fleet, headquartered in Bahrain, maintains additional capacity through Combined Maritime Forces (CMF).
Underwriters assess the IMSC presence as a meaningful but not dispositive risk-reduction factor. The key variables in their modeling are: the size and flag state of the vessel transiting; whether it carries cargo with a known Israeli, US, or otherwise politically sensitive nexus; and the prevailing regional political temperature, which has shown high volatility since October 2023.
Tanker War Risk Breach Rates
Hormuz-specific breach rates have historically been lower than Red Sea rates during the Houthi-campaign period, reflecting the different risk typology: Iranian seizure is a lower-frequency, higher-consequence event compared with Houthi missile and drone fire, which has a higher tempo but has thus far produced fewer catastrophic vessel losses among commercial transiting traffic (MV Rubymar and MV Tutor being the principal exceptions).
Current market indications for hull war-risk breach endorsements for Hormuz-transiting tankers sit at elevated but contained levels per transit, with the specific rate driven by vessel size, flag, operator reputation, cargo type, and geopolitical conditions at the time of underwriting. VLCCs and Suezmax tankers carrying crude oil from GCC ports attract slightly different terms than smaller product tankers or vessels with cargo or ownership characteristics that create heightened IRGCN interest.
Annual hull war-risk policy brackets for Persian Gulf-active vessels include Hormuz transit within the base premium calculation, with breach endorsements required for periods of elevated specific risk. War Loss of Hire (WLOH) premiums — covering revenue loss during a detention period — have become an increasingly important product for tanker operators following the multi-week detentions seen in IRGCN seizure cases.
"The Hormuz risk is fundamentally different from the Red Sea in that you're pricing a tail event — a seizure that could cost the owner months of revenue and a complex diplomatic resolution — rather than the probabilistic missile-strike scenario. The tail premium has widened." — Lloyd's tanker war risk syndicate source
GCC Routing Alternatives
Unlike the Red Sea, where the only meaningful alternative to Suez transit is the Cape of Good Hope, the Persian Gulf has a partially viable routing alternative for a subset of oil flows: the UAE East–West pipeline (Habshan–Fujairah) and the Saudi East–West Pipeline (Petroline/Aramco), which allows crude oil exports to reach the Red Sea coast and onward to global markets without a Hormuz transit.
The UAE pipeline covers a meaningful fraction of UAE crude production but is insufficient to eliminate Hormuz dependency for the broader GCC oil export market. Saudi Arabia's Petroline provides additional bypass capacity, but the combined throughput of both pipelines covers only a minority of total GCC seaborne crude flow — Hormuz remains structurally irreplaceable for the bulk of Gulf oil exports.
The Fujairah bunkering hub, on the UAE's Indian Ocean coast, has developed into one of the world's largest bunkering ports precisely because it sits outside the strait and provides a Hormuz-bypass option for bunkering and some cargo operations. Vessels diverting to Fujairah for fuel avoid an additional Hormuz transit but add time and cost compared with Port of Jebel Ali inside the Gulf.
What Insurance Buyers Should Do Now
Tanker operators and cargo interests with routine Hormuz exposure should maintain breach endorsement facilities pre-arranged with underwriters rather than seeking coverage reactively during an incident spike — the market's response to a specific IRGCN seizure episode or regional military escalation is rapid rate hardening that disadvantages late buyers.
War Loss of Hire coverage — specifically the detention scenario applicable to IRGCN-style seizures — deserves explicit review. Standard war-risk policies may not automatically extend to prolonged governmental detention; the distinction between a seizure and a confiscation matters for coverage triggering under the Institute War and Strikes Clauses.
For operators reviewing tanker war-risk exposure in the Persian Gulf and Hormuz zone, see our pillar on Marine Hull War Risk Insurance. For a binding quote, request a quote.
Related Coverage
- Marine Hull War Risk Insurance — Hull war-risk policy structure, breach endorsements, and loss of hire
- Red Sea Shipping Crisis: 2026 Insurance Rate Update — Houthi campaign comparison and JWC Listed Area status
- JWC Listed Areas Tracker — Persian Gulf boundary status and current JWC notices
- P&I War Risk Insurance — Crew liability and wreck removal in war zones
- Trade Disruption Insurance — Contingent revenue loss from transit closure scenarios