Iran Institutionalizes Hormuz Control: Formal Vetting System Replaces Ad-Hoc Passage Approvals

Iran is formalizing its control of the Strait of Hormuz by implementing a structured vetting system for commercial vessel passage.

The shift from ad-hoc threat and selective approval to an institutionalized control mechanism represents a fundamental change in how Tehran intends to use the strait as an instrument of geopolitical leverage. A crew member from an Indian LPG tanker that recently transited the strait told Bloomberg that Iranian Navy personnel directly guided the vessel through the passage on March 21, hours after UKMTO reported expanded transits of friendly-nation vessels.

What the Vetting System Means

Iran is not closing the Strait outright anymore. Instead, it is wielding what amounts to a sovereign toll booth. Analysts describe the emerging model as a tiered access system: vessels from aligned nations (India, Pakistan, China) receive cleared passage through a designated corridor. Others face mine and drone threats. The system requires advance notification, likely regulatory documentation review, and demonstrated non-hostile flag status.

This is a crucial distinction. A full closure would trigger immediate military intervention from the US and allies. A vetting system is legally defensible as a coastal state authority under international maritime law—provided Iran doesn't block neutral shipping entirely (which it currently does selectively).

The Turkish angle: Turkish-flagged vessels have also reportedly received safe passage, suggesting Iran is using selective clearance as a diplomatic signal. This week, European nations including France and Italy committed to a naval escort operation (Operation Aspides). Turkey's tacit approval of Iranian passage control indicates complex regional calculations beyond the headline conflict.

Financial Impact: The Passage Toll

At least one tanker has reportedly paid USD 2 million for the right to transit. If Iran formalizes a vetting fee structure, it could generate significant revenue while simultaneously controlling who benefits from energy trade. This transforms sanctions enforcement: even as the US temporarily lifted sanctions on Iranian oil (General License, March 20, valid through April 19), Iran's selective passage system ensures that only politically acceptable traders benefit from the relief.

Strategic Signaling

The formalization also signals durability. Ad-hoc approvals suggest temporary accommodation during a crisis. A structured system implies Tehran intends to maintain strategic control of the strait for the medium term—at least until political conditions change. This shapes investor and trader behavior: companies must assume Hormuz passage will remain contested, unpredictable, and expensive for the rest of 2026.

What This Means for Global Energy Markets

The vetting system creates a two-tier energy market. Indian refiners, which have regained access to sanctioned Iranian crude via the US waiver, can now purchase openly knowing passage is assured (as of March 21). Chinese importers face no penalty either—China's alignment with Iran is politically locked in. But European, Japanese, and Korean refiners face continued uncertainty. Their LNG imports from Qatar, which suspended operations due to Israeli strikes, remain bottlenecked.

The window for reopening the strait via traditional naval escort is narrowing. If Iran institutionalizes a vetting system, military escorts may no longer be the solution. The US military now faces the harder challenge of negotiating terms, not just defeating threats. This explains why the Trump administration has pivoted to asking allies to handle Hormuz defense rather than committing unilateral escort operations.

Precedent and Endurance

Iran has used selective passage control before. During the 1980s Tanker War, Tehran operated a de facto licensing system for vessels it permitted to pass. The current formalization mirrors that historical playbook, suggesting Tehran views this as a sustainable long-term strategy, not a temporary wartime measure.