For decades, the defense investment thesis revolved around platforms you could see: tanks, aircraft, ships, missiles. Not anymore.

The current cycle is overturning that assumption: capital is flowing into the invisible architecture of sovereignty, including autonomous systems, electronic warfare, and resilient industrial capacity, and nowhere is this shift more concentrated, more undervalued, or more politically urgent than on the seabed.

Indeed, the Iran crisis of 2026 has done for subsea infrastructure what 9/11 did for homeland security: it has transformed a long-acknowledged vulnerability into the central defense question of the decade. What had previously been treated as background infrastructure is now being reframed as strategic terrain. We believe this transition will drive a multi-year capital cycle across naval surveillance, autonomous underwater systems, cable routing diversification, and the legal-sanctions architecture that surrounds them.

The investment community has yet to fully price it in.

Before diving deeper, consider subscribing to our newsletter: you'll receive at least two free research pieces like this each month, delivered straight to your inbox.

Join 300+ investors already reading us each week!

Subscribe Today

The Hormuz Catalyst

The story crystallized in the spring of 2026. Following Operation Epic Fury, the coordinated US-Israeli strikes on Iran that began on 28 February, Tehran's response extended far beyond missiles and proxy attacks. The Islamic Revolutionary Guard Corps moved swiftly to weaponize the strait it had long threatened to close, formally declaring Hormuz shut on March 3rd, and warning it would "set ablaze" any vessel attempting passage. By mid-April, the confrontation had evolved into what The Guardian described as a "dual blockade": the US Navy restricting access to Iranian ports while Iran imposed transit tolls exceeding $1mn per vessel through the strait.

The decisive shift, however, was conceptual rather than kinetic.

In April and May 2026, IRGC-linked media outlets Tasnim and Fars published a coordinated set of proposals aimed at monetizing, and ultimately weaponizing, the seven major undersea fiber-optic cables that pass beneath the Strait of Hormuz. The framework called for licensing fees on foreign operators, "protection payments" from Meta, Amazon, and Microsoft, and exclusive Iranian authority over cable maintenance and repair.

Fars described the strategy explicitly: to transform Hormuz into one of Iran's principal levers of "digital power".

The vulnerability of subsea infrastructure had long been understood within defense and intelligence circles, but Iran's approach reframed these networks not merely as passive assets exposed to disruption, but as active geopolitical instruments capable of generating revenue, leverage, and coercive power simultaneously.

This is the doctrinal breakthrough that matters for investors.

A state actor with operational asymmetric naval forces, with roughly 60% of the IRGC's small-boat fleet surviving the war intact, is now openly framing global digital infrastructure as a coercive instrument. The cables in question carry more than $10tn in daily financial transactions and connect the AI data centers that Amazon, Microsoft and Google have spent years building in the Gulf. The 2026 Stimson Center analysis put it plainly: the security frameworks underpinning the US-UAE AI partnership were built around supply-chain control and chip export restrictions, not around physical defense during a high-intensity conflict.

Issue is, the Iranian threat is credible precisely because the proof of concept already exists.

In February 2024, Houthi attacks on Red Sea shipping resulted in the severing of four major submarine cables (SEA-ME-WE 4, IMEWE, EIG, and FALCON GCX) when a struck vessel dragged its anchor across the seabed. Microsoft Azure confirmed disruptions across the Middle East, South Asia, and parts of Europe; latency on Asia-Europe routes rose by 20 to 40 milliseconds as traffic was rerouted through SEA-ME-WE 5, while some carriers diverted around the Cape of Good Hope, adding roughly 60 milliseconds of additional delay. The model was operationally simple and strategically elegant: no divers, no specialized subsea equipment, only kinetic disruption of surface shipping with cables as collateral damage. The September 2025 cable cuts off Jeddah confirmed that this playbook had not been abandoned.

The strategic implication is sobering: Iran does not need to develop deep-sea sabotage capabilities. It already possesses a proxy network, including the Houthis, Hezbollah, and the IRGC’s asymmetric naval arm, that has demonstrated both the willingness and ability to disrupt seabed infrastructure using readily available tools.

The doctrine is exportable, deniable, and economically disproportionate, delivering outsized disruption relative to its low operational cost.

What gives the Iranian theater its weight is that it is no longer an isolated case: the Baltic Sea has functioned as a parallel laboratory for grey-zone subsea warfare since 2023. The January 2026 damage to the Elisa cable connecting Finland and Estonia, reportedly involving a vessel named Fitburg , joined a growing inventory of incidents that prompted NATO's Baltic Sentry mission, the EU's February 2025 Action Plan on Cable Security, and ultimately the US Strategic Subsea Cables Act of 2026.

The doctrinal convergence between Moscow’s "shadow fleet" tactics and Tehran's emerging cable doctrine is what makes this a structural theme rather than a regional flare-up. Two of the world’s most active sub-threshold adversaries are independently arriving at the same conclusion: seabed infrastructure offers one of the highest strategic returns per dollar of operational investment in the modern conflict landscape.

The Asymmetry that Drives the Investment Case

The economics here are extraordinary, and they map directly onto the lessons of Ukraine: just as a €500 FPV drone now neutralizes a €5mn main battle tank, a $50,000 sabotage operation (with a chartered vessel, a dragged anchor, and plausible deniability) can disrupt $10tn in daily financial flows, and the degradation the AI infrastructure of an entire region.

The European Industrial Complex of Missiles and UAVsOver the past decade, Europe’s defense technological and industrial base has been reshaped by the combined force of long-term integration and sudden geopolitical disruption. Consolidation across the sector has progressed steadily since the end of the Cold War, but the Russian invasion of Ukraine in 2022 marked a clear inflectionQuartz Sea ResearchAnalytical Team

The "cost-per-disruption" asymmetry on the seabed is even steeper than in the air, and the defensive response correspondingly expensive.

There are three structural realities ensuring this capital cycle will sustain:

1. First, repair capacity is the system's hidden chokepoint. Only 63 specialized cable repair ships operate worldwide, with just two to four stationed in the Middle East. A single repair can take at least 40 days, and costs between $1mn and $3mn, assuming access to territorial waters is granted. War-risk underlying has already halted new cable construction across both the Persian Gulf and the Red Sea, while Meta's 45,000km 2Africa project has faced delays from both Houthi attacks and Operation Epic Fury.
2. Second, the attribution problem makes deterrence structurally difficult. UNCLOS Article 79 protects cable-laying rights, but the law of the sea was not drafted with grey-zone hybrid warfare in mind. What is now being called "sea lawfare", meaning the weaponization of legal ambiguity around territorial waters, innocent passage, and accidental damage, gives adversaries a doctrinal shield that conventional military deterrence cannot easily pierce.
3. Third, the dual-use industrial base is already mobilized. The same autonomous underwater vehicles that survey offshore wind farms and inspect oil pipelines can also hunt mines and patrol cables; the same hyperscalers building Gulf AI infrastructure are effectively becoming frontline operators by default: this convergence accelerates capital deployment, because the underlying technologies are already commercially mature.

The Five Pillars of Subsea Capital Allocation

(table can be scrolled horizontally)

The underwater drone market alone is projected to reach $16bn by 2034, while Saab's marine division is forecast to grow at an 11% CAGR through 2027.

The Scaling of Saab: From Niche Player to NATO PillarQuartz Sea Research initiates coverage on Saab AB (SAAB.B-SE) with an “Outperform” rating and a target price of SEK 602.61, representing an 7.6% upside from the current market price of SEK 560.00. Three years ago, Saab was a “niche” Nordic specialty shop; today, it is theQuartz Sea ResearchAnalytical Team

DARPA's "Deep Thoughts" program, launched in April 2026, is explicitly soliciting next-generation AUV designs capable of full-ocean-depths operations. Sweden's March 2026 follow-on order to Teledyne for additional GAVIA systems, placed during the Navy Tech Conference in Gothenburg, is the kind of repeat procurement that signals these are not one-off acquisitions, but rather the early stages of a multi-decade fleet build-out.

Conclusion

The conventional defense thesis priced subsea infrastructure as a peripheral concern, a niche within naval procurement and a sub-line NATO communiqués, but the Iran crisis has changed that. When the IRGC openly frames undersea cables as a "digital power lever", it makes explicit what Russia has demonstrated more tacitly in the Baltic: the seabed is now a recognized war-fighting domain, on par with space and cyber, and its defense will require a corresponding industrial response.

For strategic investors, the convergence is increasingly clear: persistent surveillance fleets, autonomous underwater capabilities, cable hardening technologies, routing diversification, and the legal and sanctions architecture that binds them together form a coherent investment pillar within the broader Sovereign Fortress thesis.

The cycle is still in its early stages.

The era of treating the seabed as benign infrastructure is ending, and the capital cycle that will replace it has only just begun.

Sign up for Quartz Sea Research

Independent equity research: actionable, fully digital, and results-driven.

Subscribe Today

Email sent! Check your inbox to complete your signup.

No spam. Unsubscribe anytime.