Iran's Hormuz bill prices the chokepoint: 7% to pass, 20% to refuse

Iran's parliament is reviewing legislation that would give Tehran regulatory control over transit through the Strait of Hormuz, barring vessels linked to the United States, Israel and other states it treats as hostile unless they pay compensation for war-related damages ^[1]. The bill proposes transit fees reaching 7% of a vessel's cargo value, and Iranian state media reports that fines for non-compliance could reach 20% ^[2][4] - which converts a chokepoint from a scenario in a war game into a line item on a voyage estimate.

The bill was announced by Iranian lawmaker Mohammad Reza Rezaei Kouchi on April 19, 2026 ^[3]. Roughly one-fifth of world oil consumption moves through the waterway between Iran and Oman ^[5].

The instructive number is the ratio, not the headline rate. At 7% to comply and 20% to refuse, refusal is priced at about 2.9 times compliance ^[1]. That is not the arithmetic of a blockade; it is the arithmetic of a toll designed to be paid. A blockade forces a decision by governments. A tariff forces a decision by charterers, owners and underwriters, one voyage at a time, and each of those parties has a commercial incentive to settle rather than test the principle.

The legal ground is deliberately unsettled. Iran's justification rests on domestic statutes including the 1964 Maritime Code and the 1993 Act on Marine Areas ^[8], and Iran has never ratified key provisions of the UN Convention on the Law of the Sea, which leaves Tehran room to argue its own reading of transit rights takes precedence ^[9]. For a shipowner, that means the dispute is not about whether the charge is lawful in the abstract but about which body of law an eventual claim is heard under - and there is no obvious forum.

The institutional sequence is the tell. Iran established the Persian Gulf Strait Authority on May 5, 2026 ^[10], sixteen days after the bill was announced ^[2]. Iran has been blocking shipping through the strait since February 2026, and the legislation would retroactively provide legal cover for action already underway ^[7][11]. The collecting body and the conduct came first; the statute is being fitted around them. As of early August 2026, Iran, Oman and the United States were negotiating an interim agreement on shipping routes and management of the strait ^[12] - roughly six months after the disruption began ^[3].

The precedent everyone reaches for is the 1980s Tanker War, when attacks on commercial shipping in the Persian Gulf disrupted oil flows and drew direct US military intervention ^[13]. A published fee schedule is a different instrument with a different escalation path. The most exposed buyers are in East Asia, where Japan, South Korea and India all take substantial portions of their crude through the Hormuz corridor ^[14][15].

Watch three things. Whether the 7% and 20% figures survive drafting, or were opening positions for the Oman and US talks. Whether the interim agreement substitutes a negotiated regime for the tariff, which would tell you Tehran wanted a seat rather than the revenue. And whether any owner pays - because the first paid transit sets the reference price, and once a charge has been paid once it stops being an act of war and starts being a cost that has to be allocated between charterer, owner and war-risk underwriter in every fixture that follows.