According to Willis Re, the marine war risks market, once a quiet, predictable corner of global reinsurance, is being reshaped by renewed geopolitical tension and rising aggression at sea.
The firm traces this evolution back to the late 19th century, when Lloyd’s underwriters formally separated “risks of the seas,” such as weather and collision, from “risks of men,” like enemy action. This historic split created the foundation of modern marine war risk insurance.
For decades, the segment remained subdued. International treaties curbed naval hostility, piracy fell under control, and reinsurers treated war risk as a manageable specialty line.
However, Willis Re’s recent analysis shows that the stability of the past century has now vanished. The company points to a sharp escalation in maritime hostilities, both state-sponsored and covert, that is redefining risk exposure for insurers and reinsurers alike.
Willis Re highlights several flashpoints driving this change. Iranian and Israeli forces have exchanged strikes on shipping in the Strait of Hormuz. Chinese authorities continue to disrupt trade routes in the South China Sea. Houthi militants have launched missiles, drones, and explosive boats against commercial vessels in the Red Sea since late 2023.
In the Black Sea, tankers have been damaged by Ukrainian rockets, while piracy has again emerged off the Somali coast. Even US naval actions against smuggling vessels in the Caribbean and Pacific have added to the perception that the world’s shipping lanes are increasingly volatile.
The firm notes that many of these incidents fall into what it calls the “gray zone” of conflict—aggressive acts that stop short of open warfare but still serve political or economic goals. This type of hybrid pressure, according to Willis Re, has become one of the defining characteristics of today’s marine war risk environment.
In addition to physical attacks, Willis Re draws attention to a growing wave of cyber interference targeting the maritime sector. Spoofing operations, where vessels are fed false GPS or AIS data, are occurring daily, often to disguise ship movements or cause navigational disruption. The company warns that these attacks can even interfere with automated underwriting systems that depend on vessel tracking data, blurring the line between physical and digital warfare at sea.
Willis Re explains that reinsurers have responded by tightening terms and exclusions in their treaties. The first step was the introduction of “RUB” exclusions, restricting coverage for ships linked to Russia, Ukraine, or Belarus. Later, reinsurers pushed for war risks to be removed from charterers’ protection and indemnity (P&I) policies, forcing separate, sub-limited coverage that in some cases costs more than traditional P&I protection.
The firm also warns that “accumulation risk,” once considered minimal in marine lines, is becoming an unavoidable reality.
Willis Re recalls how the COVID-19 pandemic exposed this vulnerability when dozens of cruise liners were immobilised off the US coast under a government no-sail order, leaving more than 90,000 crew stranded.
Similar risks surfaced during Russia’s invasion of Ukraine, when numerous merchant vessels were trapped in ports like Mariupol and Odesa. While marine reinsurers escaped major losses then, the corresponding aviation market suffered a severe financial blow from aircraft seizures, which Willis Re says served as a wake-up call across the industry.
Reinsurers are now introducing treaty restrictions to limit exposure to these clustered events, including geographical aggregation controls. Willis Re cites the recent drone strikes at Tuapse, a Russian Black Sea port, where multiple tankers were damaged, as a real-world example of accumulation risk materialising.
Even though some affected vessels were part of the so-called “shadow fleet” circumventing sanctions, Willis Re notes that many of them remain indirectly covered through international reinsurance channels, exposing global markets to unexpected liabilities.
Another concern, according to Willis Re, is the imbalance in war risk premium pools. As vessels reroute away from high-risk areas like the Red Sea, fewer premiums are collected along the original routes, reducing the funds available to absorb potential losses. The firm cautions that a single major loss could easily exceed the total premiums written for those regions, making pricing sustainability a critical issue.
On the cyber front, Willis Re observes that most reinsurers have now moved to exclude conflict-related cyber operations altogether. It points to the Lloyd’s Market Association’s LMA5630 clause, which removes protection for cyberattacks tied to warfare or state-sponsored disruption, a standard that many treaties have since adopted.
Despite these mounting complexities, Willis Re reports that the wider marine insurance market is softening. New capital continues to enter through managing general agents and facilities, driving down rates even in the face of heightened global risk. Losses from recent conflicts have, for the most part, remained within manageable limits, and the firm anticipates competitive conditions heading into the 2026 renewal season.
Yet, Willis Re concludes, the stability of past decades is gone. The reinsurance industry must now contend with a world where war, cyber aggression, and sanctions exposure interact in unpredictable ways. As reinsurers adapt their models to account for environmental changes, political volatility, and clustering risk, Willis Re warns that the coming renewals will be marked by both competition and caution.
