The $40 Billion Question in the Strait: Iran’s Bid to Tax the World’s Oil Choke Point

For several weeks the world’s most consequential waterway has been a hostage of somebody else’s arithmetic. On 25 June 2026, the United Nations International Maritime Organization paused a ship-evacuation programme it had been running for Hormuz-bound commercial traffic, after another vessel was struck. Tehran, in parallel, told shipping companies to use only state-approved transit corridors. The combination — an international agency withdrawing escort capability while an Iranian naval and quasi-military apparatus asserts routing authority — is the condition that produced the new fight over who gets to charge what for passing through a strait the world’s tanker fleet cannot bypass.

The numbers now in circulation are not small. According to projections circulating in regional reporting on 25 June, Iran is estimating roughly $40bn a year in revenue from a Hormuz transit fee regime, were one to be tolerated. That figure is roughly the annual export earnings of a mid-sized Gulf petrostate, and it is being floated at the precise moment the International Maritime Organization (IMO) has acknowledged it cannot guarantee safe passage. The market is voting, quietly, on whether any of this holds. A prediction market on Polymarket puts the odds of Hormuz traffic returning to normal by 31 July 2026 at 54% — better than even, but only just — and assigns just a 2% probability that the United States agrees to any arrangement that lets Tehran collect transit fees.

The US position is publicly absolute. On 25 June, Secretary of State Marco Rubio stated there is "zero support from gulf countries for tolls or fees on Strait of Hormuz." That formulation matters. It does not say the United States alone opposes tolls; it says the Arab monarchies on the waterway’s southern shore oppose them too. Saudi Arabia, the United Arab Emirates, Oman and Qatar sit on the strait alongside Iran. If Washington’s reading of Gulf sentiment is accurate, Tehran is bidding for revenue from a regime it cannot enforce on its own. If it is inaccurate — if Doha or Muscat privately tolerates a deal that gives Tehran face in exchange for a stable corridor — the politics of the Gulf shift.

What the UN pause actually signals

The IMO’s evacuation initiative is the part of the story that does not have a price tag attached. The agency’s decision, reported on 25 June, to halt its ship-evacuation programme after a vessel was attacked turns a bureaucratic operation into a market signal. Once the international body responsible for maritime safety withdraws escort capability, tanker owners default to two strategies: pay the implicit premium for sailing with private security and higher insurance, or divert around Africa via the Cape of Good Hope, adding roughly 10 to 15 days and substantial fuel cost to every voyage.

The effect shows up in freight rates long before it shows up in crude prices. The BBC reported on 25 June that oil has fallen to levels not seen since before the war with Iran began — a counter-intuitive print, given that the strait is functionally compromised. The mechanism is partly demand destruction and partly the slow-release of strategic petroleum reserves by importing states. But the freight market, which responds in days rather than weeks, is signalling that somebody is still moving product through the strait. Reporting from the shipping trade press indicates that some tanker owners are being drawn back into Hormuz by unusually high day-rate offers from charterers — a euphemism, in practice, for shipowners being paid enough to overcome their insurance underwriters’ reservations. That is what “lured back… by big payouts” looks like in a freight market.

The Hormuz dispute is therefore two intertwined fights. The first is a physical fight over navigation: who can threaten, escort, mine, or drone a tanker in a 21-nautical-mile channel, and who can deter them. The second is a legal-fiscal fight over whether any sovereign can lawfully collect a transit fee in a strait the United Nations Convention on the Law of the Sea designates as one used for international navigation. The two fights are running on different clocks. The physical fight is being adjudicated by Iranian fast boats, US carrier strike groups, and an Israeli air force that has already struck Iranian assets on the southern shore. The legal-fiscal fight is being adjudicated, for now, by Polymarket bettors and the public postures of Gulf foreign ministries.

The Iranian revenue arithmetic

The $40bn figure deserves unpacking. Iran’s projection assumes a transit fee on a meaningful share of the roughly 20 million barrels of oil and the large volumes of liquefied natural gas that pass through the strait each day, applied to a chokepoint no vessel can meaningfully bypass if it is calling at Gulf loading terminals. The number is plausible only if three conditions all hold: shipping obeys the routing requirement, Gulf producers do not unilaterally cut production to choke demand for the corridor, and the United States does not retaliate militarily at a level that prices Iran out of collecting.

Each condition is fragile. Gulf producers sitting on the same waterway have every incentive to refuse to route via Tehran-approved channels, because doing so legitimises Iranian sovereignty over a corridor they themselves use. A coordinated Saudi-Emirati refusal to participate would push the fee regime into an Iran-only-versus-everyone-else framing, which is precisely the framing Rubio has tried to install with his “zero support” line. The US carrier presence in the Gulf is the backstop. Iranian fast boats can harass; they cannot safely collect fees from a tanker carrying the wrong flag under the eye of a guided-missile destroyer.

The number is therefore best read not as a forecast but as an opening bid in a negotiation whose other parties have not yet agreed to sit down. It is the kind of figure that gets floated in a press cycle to test reaction. That Tehran chose to float it now — in the same week the IMO withdrew its escort programme and the US Secretary of State made his declaration — suggests the Iranian strategy is to anchor the conversation in fee revenue, in dollars, at a scale large enough to be attractive to a Gulf interlocutor who might be brought into the deal, even as Washington insists no deal is on offer.

What the Gulf actually wants

Gulf states have reason to oppose a toll regime that is more subtle than it appears. A fee collected by Iran at Hormuz would, in effect, be a tax on Saudi and Emirati crude at the moment of export, paid to a regional rival. It would also set a precedent: if transit through Hormuz can be tolled, then transit through Bab el-Mandeb, off Yemen’s coast, can be tolled; transit through the Malacca Strait could in principle be tolled. Every small strait in the world becomes, suddenly, a rentier opportunity for the sovereign whose coast it borders. The Gulf monarchies understand this. They have spent two decades building pipelines and terminal capacity precisely so that their oil does not all have to exit through Hormuz, and they are not going to underwrite an Iranian claim to revenue from infrastructure they helped the world take for granted.

The structural frame matters. The strait is the canonical case of a global commons whose protection has been outsourced, by default, to the United States Navy for forty years. The fee question is therefore not only a question about oil. It is a question about who underwrites the security of the maritime corridors on which the dollar-denominated energy trade depends. If Tehran successfully monetises Hormuz, it has converted a piece of geography into a claim on the dollar system that prints the prices its customers pay.

That is also why Washington’s framing matters more than the fee arithmetic. The Rubio line is doing two things at once. It tells the markets that there will be no negotiated toll regime. And it tells Gulf governments that if they quietly participate, the United States will treat that participation as a hostile act. Whether Gulf governments accept that framing — or decide that a face-saving formula with Tehran is preferable to a permanent US naval bill — is the political variable the next four weeks will resolve.

Stakes and the road to 31 July

If traffic normalises by 31 July, the fee question withers for the cycle: the physical risk is priced, the tankers return, and the Iranian revenue projection goes back to being a thought experiment. If traffic does not normalise — if the IMO stays out, the shipping rates stay elevated, and at least one Gulf producer quietly accepts an Iranian corridor — the question migrates from the editorial page into the treasury department. Insurers, who have effectively withdrawn war-risk cover on parts of the strait, are the closest thing the shipping industry has to a real-time poll. They will price any regime change weeks before diplomats confirm one.

The Polymarket number is, in that sense, the most honest single indicator available: a 54% chance that the situation is unrecognisable a month from now, and a 2% chance that the United States signs on to the revenue model. Both readings can be true at once. The market believes the physical situation will be manageable; the market does not believe Washington will accept the fiscal arrangement Iran is shopping. That gap is the diplomatic problem in a single spread.

What remains genuinely uncertain is the variable the wire reporting does not yet capture. There is no public read on whether any Gulf foreign ministry has been approached privately with a corridor arrangement that does not call it a “fee." There is no public read on whether the Iranian projection is a serious negotiating number or a public posture designed to be walked back. And there is no public read on what happens if the IMO’s pause extends beyond a fortnight and a major incident in the strait — a strike on a non-military vessel with crew casualties — reframes the political conversation overnight.

What is certain is the structure. A $40bn figure, a 2% Polymarket probability, a zero-tolerance statement from the Secretary of State, and a UN agency in retreat. The market, the bureaucracy, and the cable traffic are all pointing in the same direction: this is a question about who pays for the security of a corridor the global economy cannot reroute around, and the answer is being negotiated in real time.

Desk note: this publication led with the IMO evacuation pause and the Iran revenue projection as twin beats of the same story, rather than treating the fee figure as a one-day headline. Wire reporting on 25 June emphasised the market reaction and the US rejection; Monexus frames the dispute as a test of the post-1970s arrangement under which US naval power, not regional sovereignty, has guaranteed the strait’s usability.

Wire provenance

This editorial synthesis draws on the following public wire/social posts:

• https://x.com/unusual_whales/status/
• https://x.com/unusual_whales/status/
• https://x.com/polymarket/status/