The Strait of Hormuz is reopening after a four-month blockade, but the marine insurance market is entering unfamiliar territory — one where the legal, operational, and sanctions-related questions are far from settled.
Windward, a maritime intelligence company, hosted an executive briefing on June 18, 2026, to assess what the cautious reopening means for underwriters, P&I clubs, and brokers. The picture that emerged is one of incremental movement rather than normalization, with several major risk questions still open.
The MOU and What It Resolves
A U.S.-Iran memorandum of understanding, electronically signed by both presidents and in effect as of June 17, 2026, formally triggers the reopening of the strait. According to Windward’s briefing, the agreement confirms a 60-day toll-free transit window and authorizes the immediate removal of the U.S. naval blockade.
But the post-window picture is already contested. Iranian officials have indicated they will establish a new management regime for the strait alongside Oman and charge fees for services — a position that directly contradicts the U.S. characterization of the strait as permanently toll-free. What comes after day 60 is an open question heading into the final negotiation period.
Sanctions Exposure: No Gray Area
For the insurance market, the toll question carries direct sanctions implications. Mark Church, Head of Sanctions Function at NorthStandard, noted during the briefing that any vessel paying a toll to a sanctioned entity faces significant risk.
According to Windward’s summary of the briefing, OFAC guidance issued in early May 2026 goes further: even where no payment has been made, receiving a safe-passage guarantee from Iran can itself create sanctions exposure for both the shipowner and any insurer providing cover. The Persian Gulf Strait Transit Authority, established by Iran to collect tolls, has been sanctioned by OFAC. The IRGC, which controls passage through the strait, is subject to U.S., EU, and UK designations.
The operational implication, as reported by Windward, is clear: a vessel that has paid a toll or received an Iranian safe-passage guarantee cannot be insured by any P&I club or war risk underwriter.
The CTL Clock Is Running
Beyond sanctions, stranded-vessel exposure is becoming materially real for insurers and insureds alike. David McKee, referenced in Windward’s briefing, noted that most war risk clauses set a 12-month detention threshold before a constructive total loss claim can be made, with some policies still operating on a 6-month period.
As of early June 2026, roughly 530 cargo ships and tankers were signaling west of Hormuz via AIS, with an estimated 200-plus dark vessels in the same waters — including approximately 50 VLCCs. For vessels stranded since the blockade began, the CTL clock is no longer a theoretical concern.
Loss of hire claims are also starting to come through. Windward notes that not every loss of hire policy will respond without physical loss or damage, though some policies cover blocking and trapping risks.
Charter Party Disputes and War Risk Premiums
David McKie, Partner at Preston Turnbull, highlighted in the briefing that most modern charter parties include provisions for allocating additional war risk premium costs between owners and charterers — typically through BIMCO clauses including CONWARTIME 2013 and 2025, and VOYWAR. Owners generally seek to pass these costs to charterers, though subtle differences between clause editions can affect outcomes.
Practical problems around evidence quality have also emerged, particularly whether premium increases can be clearly demonstrated as area-specific rather than blanket policy adjustments.
Traffic Picture Remains Thin
The operational data from Windward reinforces the cautious tone. Over May 2026, the company tracked 156 transits through the strait, 22% of which were dark. The June 1–7 window recorded 51 transits, with 27% dark. In the days immediately following the MOU announcement, movement remained minimal, with hundreds of vessels still holding position on either side.
Demining operations to clear the Traffic Separation Scheme remain a key gating factor. The MOU sets a 30-day window for demining to begin, but Windward estimates that a verified mine-free corridor will take roughly two months, with full clearance taking considerably longer.
Does This Matter to You?
The reopening of the Strait of Hormuz ends a period of near-total closure, but it does not end the complexity surrounding it. The unresolved toll structure, persistent sanctions exposure from Iranian safe-passage guarantees, and the approaching CTL thresholds for hundreds of stranded vessels represent active risk factors — not historical ones. The high proportion of dark transits means that AIS-based visibility alone is insufficient for underwriting decisions in the current environment.
The 60-day toll-free window provides a temporary buffer, but the structure of what follows remains contested between the U.S. and Iran, and the sanctions framework does not change based on how either side characterizes the outcome.
Gulf Bunkering does not provide operational or security guidance. This article is for informational purposes only. Operators should consult flag state authorities, P&I clubs, and relevant advisories for decisions relating to transit planning.
Sources: Windward
