What Marine Underwriters Are Now Pricing Against

At a Glance

• Marine underwriters price risk at binding and reassess at renewal, and both decisions depend on data inputs that have become structurally less reliable across 2026.
• The AIS-based voyage history that underpins historical loss modeling has been compromised by GPS jamming, with 171,286 distinct vessels affected globally in Q2 2026 and 3.35 million false ship-to-ship meetings recorded since Operation Epic Fury began on February 28, 2026.
• Prolonged dark activity surged sevenfold quarter-over-quarter, from 451 events in Q1 2026 to 3,137 in Q2, meaning a significant share of vessels are now spending extended periods without self-reporting position.
• Declared documentation is increasingly unreliable, with 275 tankers broadcasting fraudulent registry flags in Q2 2026 and 22 fraudulent ship registries now identified.
• P&I clubs raised the Excess War Risk sub-limit for vessels trading in Russia, Ukraine, and Belarus waters from $100 million to $125 million for the 2026/27 policy year, signaling that market capacity is repricing war-adjacent maritime risk.
• Pricing accuracy now depends on behavioral intelligence and all-source operational intelligence that verifies what vessels actually did, independent of what their broadcasts or documents claim.

Underwriting Is a Pricing Decision Made on Incomplete Data

Underwriters carry the pricing decision at two moments in the coverage process. At binding, the underwriter takes compliance’s assessment of the vessel and its operating context, applies actuarial models and loss history, and sets premium and terms. At renewal, the underwriter takes the full term’s monitoring history plus any claims that occurred and decides whether to renew, reprice, or decline.

Both decisions depend on the accuracy of the risk picture being priced. Across 2026, that accuracy has been under pressure in ways older loss models cannot easily accommodate.

Three specific shifts define what marine underwriters are now pricing against.

Shift One: AIS-Based Voyage History Is Structurally Less Reliable

AIS-based voyage records are a core input into marine loss modeling. Whatever tolerance for data quality those models build in, the accuracy of the underlying record has been eroding, and in 2026 the erosion has reached a scale that matters for pricing.

Windward tracked 171,286 vessels affected by GPS jamming at least once globally in Q2 2026. Since Operation Epic Fury began, 3.35 million false ship-to-ship meetings have been recorded, in which injected positioning coordinates made vessels appear to rendezvous when no meeting took place. False meetings peaked on March 20 at 356,773 in a single day. Jamming is persistent in the Middle East Gulf, the Black Sea, the Mediterranean, and other high-exposure regions, which is exactly where the vessels underwriters most need to accurately price are operating.

This creates two specific problems.

Historical loss modeling built on voyage histories from jamming-affected regions is modeling against data that includes injected positions, missing periods, and false event records. A vessel that shows a clean voyage history through a jammed region may have called at ports its AIS did not record. A vessel that shows sanctioned port calls may have been broadcasting injected positions that never occurred.

The same corruption then runs forward. For any vessel operating in or transiting jamming-affected regions, AIS-based monitoring during the policy period will be distorted the same way the historical record was. The underwriter reaches the end of the term without a clean account of what the vessel did while covered, which means the renewal reassessment starts from the same compromised position as the original binding. The gap does not close over time. It compounds across cycles.

Shift Two: Prolonged Dark Activity Has Surged

Windward’s Q2 2026 Maritime Risk Report tracked 2,157 unique cargo ships and tankers over 10,000 DWT conducting at least one dark activity event lasting more than three days during Q2, nearly five times the 449 vessels recorded in Q1. The number of prolonged dark activity events rose from 451 in Q1 to 3,137 in Q2, a sevenfold increase quarter-over-quarter.

For an underwriter, this matters because prolonged dark activity is a period during which a vessel could have conducted port calls, ship-to-ship transfers, cargo movements, or other operations that the AIS record does not capture. The underwriter pricing a vessel with a history of prolonged dark activity is pricing against a record with known gaps. The underwriter pricing a vessel without prior dark activity has less certainty that the vessel will not develop dark activity during the policy period.

Russia alone recorded nearly 4,000 dark activity events in Q2, and the Middle East Gulf jurisdictions of Saudi Arabia, Oman, Iran, and the UAE collectively accounted for one in four extended dark events globally. Vessels stranded during the Hormuz closure earlier in Q2 frequently switched off AIS for safety and security reasons. Legitimate dark activity in these regions is well documented. Illicit dark activity concealed within the same operational conditions is also documented.

Distinguishing legitimate dark activity from concealment for pricing purposes is where the analytical work concentrates. A vessel that went dark for stranding-related safety reasons carries a different risk than a vessel that went dark to conduct a ship-to-ship transfer with a sanctioned counterparty. Static AIS-based pricing cannot make this distinction. Behavioral analysis can.

Shift Three: Declared Documentation Is Increasingly Unreliable

Vessel identity screening has traditionally relied on declared flag, registered ownership, and IMO documentation. Underwriters have historically been able to work from this documentary picture as a reasonable proxy for actual vessel identity.

In 2026, that picture has become materially less reliable.

Q2 2026 saw 275 internationally trading tankers broadcasting the flag of a fraudulent registry, with 22 distinct fraudulent ship registries now identified.

Russia-linked tankers falsely claimed the flags of Syria and Myanmar during Q2 for the first time. Approximately 60 tankers moved from fraudulent registries to Russia’s own flag in the first half of 2026, a shift driven by enforcement rather than commercial preference. Vessels under fraudulent registries lack flag-state protection and can be boarded under UNCLOS, and after U.S., UK, and French interdictions of stateless tankers began in December 2025, reflagging to Russia became the route back to legal protection.

Of approximately 430 tankers currently active in the Iran trade, 62% are falsely flagged, and 87% are sanctioned. For a substantial share of the tanker fleet operating in high-exposure trades, the declared flag does not reflect the actual authorized flag, and the ownership chain declared in the documentation may not reflect the actual beneficial owner.

For pricing purposes, this changes what the documentary picture represents. Neither Syria nor Myanmar operates an international ship registry. Any tanker broadcasting either flag is falsely flagged by definition, and the declared identity has no issuing authority behind it at all. A tanker presenting an ownership chain that traces through single-ship SPVs, Russia-incorporated management entities, and opaque registered ownership may be presenting an identity structure designed to defeat beneficial ownership screening.

The market has responded. The insurance certificate itself has become a piece of evidence in the sanctions enforcement environment, and the U.S. SHADOW Fleet Sanctions Act of 2026 (S.2904), if passed, would make lack of adequate marine insurance a sanctionable condition for vessels moving certain Russian commodities. For tankers moving Russian oil, uranium, or coal, the presence or absence of legitimate insurance is a first-order sanctions consideration. By implication, the underwriter’s confidence in the vessel’s actual identity becomes a first-order pricing consideration.

What the Market Is Signaling

P&I clubs raised the Excess War Risk sub-limit for vessels trading in Russia, Ukraine, and Belarus waters from $100 million to $125 million for the 2026/27 policy year. War-risk premiums for Strait of Hormuz transits have moved from roughly 0.25% of hull value in the pre-conflict period to 3-10% of hull value at various points through 2026. Neither adjustment reflects a temporary correction. Both reflect the market’s assessment that the operational environment ahead requires materially more capacity to cover the risks that are actually present.

For underwriters shaping renewal pricing in the second half of 2026 and into 2027, these are the reference points. Capacity providers have already adjusted their assessment of what the environment requires. A renewal priced off the pre-2026 picture is priced against conditions the capacity behind it no longer assumes.

The Renewal Reassessment

At renewal, the underwriter reassesses the vessel or fleet using the full term’s monitoring history plus any claims that occurred. This is where the accumulated intelligence from the just-ended term flows into the pricing decision for the next term.

The quality of that reassessment depends on what compliance monitored during the term and what the monitoring surfaced. A vessel that showed clean AIS throughout the term but exhibited behavioral pattern shifts worth flagging looks different at renewal than a vessel with an unremarkable operating history. A vessel that entered jamming-affected regions during the term and returned with reconstructed activity that supports the underwriting picture looks different from a vessel with unexplained dark periods.

The renewal is also where accumulated environmental context becomes decisive. Standard sanctions clauses handle the mechanical part, obliging the insured to comply with whatever measures are in force. What they do not resolve is that the measures are no longer converging. The EU’s 21st sanctions package, adopted July 23, 2026, and the OFAC-OFSI comparative framework published a month earlier describe overlapping but non-identical perimeters. A vessel can sit inside one regime’s restrictions and outside another’s, and a clause that says “comply with applicable sanctions” does not tell the underwriter which side of which line the vessel is on.

Without that picture, the renewal reprices a vessel whose actual regulatory exposure the underwriter cannot fully see.

How Windward Supports Marine Underwriters

Windward’s Maritime AI™ Platform provides the vessel identity, behavioral intelligence, and multi-sensor verification through all-source operational intelligence that underwriters need to price accurately in the current environment.

Know Your Vessel (KYV™) consolidates the vessel-specific picture that underwriters need at binding and at renewal. Ownership tracing surfaces the beneficial ownership behind declared entities. Flag history reveals patterns of flag hopping or fraudulent registry use. Identity change tracking captures cases where a vessel has changed name, IMO number, or declared registration in ways that mark shadow fleet activity. For a vessel presenting itself under a Syrian, Myanmar, or other fraudulent registry, KYV™ surfaces the operational history and ownership structure that the declared flag conceals.

Behavioral risk profiling surfaces the operating patterns that distinguish legitimate maritime activity from shadow fleet, sanctions evasion, and cable-proximate risk behavior. A vessel that loiters above subsea cables, conducts ship-to-ship transfers in atypical circumstances, or exhibits dark activity patterns inconsistent with legitimate operational rationale is priced differently than a vessel with a comparable declared profile but no such behavioral history.

All-source intelligence incorporates all sources of information in the production of finished intelligence. Applied to marine underwriting, Windward’s all-source fusion combines AIS with satellite imagery (SAR and EO), radio frequency detection, ownership records, sanctions data, behavioral history, and any additional sources the underwriter’s assessment requires. The output is sensor-verified vessel activity that supports pricing decisions even when AIS is compromised, dark activity conceals portions of the operating record, or declared documentation does not reflect actual identity.

For underwriters at binding, this means pricing against a picture that reflects what the vessel actually is and does, rather than what its documents claim. For underwriters at renewal, this means arriving at the reassessment with a documented monitoring history of what happened during the term.

Where This Is Heading

The environment that has emerged in recent years is not returning to the previous baseline. GPS jamming will continue in the Middle East Gulf while the Iran conflict remains unresolved. Prolonged dark activity will remain elevated while Russia and Iran continue to operate under sustained sanctions pressure. False flag operations will continue to evolve.

Underwriters pricing marine insurance against this environment need pricing infrastructure that keeps up with the pace of change. Static AIS-based history, declared documentation, and periodic behavioral snapshots cannot deliver the pricing accuracy the current environment demands. Behavioral intelligence, multi-sensor verification, and continuous monitoring can.

The underwriters who invest in this pricing infrastructure are the ones whose portfolios will hold up across the coming renewal cycles. The underwriters who continue pricing against previous assumptions are accumulating exposure that will show up in the loss picture over the next several years.

Written by Maya Romi, Windward Maritime Intelligence Content Specialist. Reviewed by Angela Freeth, Product Marketing Manager, Commercial.