Hormuz Is Not Closed, Yet No Longer Reliable

The received view of the Strait of Hormuz is binary: either Iran has closed it, or the waterway remains open. That distinction misses the strategic fact of the fortnight. Between 28 August and 11 September, US Central Command reported mine clearance, escorted shipping and strikes on Iranian maritime assets; Iranian authorities claimed control over transit, threatened unauthorised vessels and reported attacks on US-linked targets; Kpler recorded only a handful of commodity-vessel movements on several days. The evidence does not establish a complete physical closure. It does establish something more consequential than a temporary navigational scare: Hormuz has become commercially unreliable. I would hold that functional restriction, rather than legal closure, is the correct measure of the crisis, because uncertainty is already reducing movement, increasing costs and narrowing the choices available to exporters, buyers and naval forces.

Functional restriction means that ordinary commercial passage cannot be planned or insured on ordinary terms, even when selected vessels continue to move. The mechanism is commercial self-deterrence: contested attacks and navigation rules raise the perceived chance of detention, damage or crew evacuation; insurers and operators then impose exceptional conditions; traffic falls, cargoes are delayed or rerouted, and the remaining passages become politically or militarily managed rather than routine. Kpler recorded seven tracked transits on 9 September against a 10-day average of 14, while no LNG tanker was recorded leaving that day. Rystad separately estimated oil flows below 2 million barrels per day, compared with roughly 8 to 9 million before fighting resumed on 30 August. Vitol claimed that a shuttle arrangement was still moving about 10 million barrels per day through the wider Gulf of Oman system. These figures cannot be combined into a single flow measure, but their divergence is itself revealing: movement persists, though predictability has not.

The military exchange supplied the uncertainty through which this mechanism operates. On 30 August, US Central Command said it struck two Iranian launchers on Larak Island because the Islamic Revolutionary Guard Corps was preparing them for mine deployment. Iranian reporting then described missile and drone activity towards Jordan, while the Jordanian Armed Forces reported interceptions near Al Azraq. On 5 September, the IRGC claimed missile fire against a US aircraft carrier and a guided-missile destroyer; Central Command said US forces struck the tankers Downy, Stark 1 and Kylo, also called Noxen in other accounts. By 9 September, the IRGC reported another attack towards Muwaffaq Salti Air Base, and Jordan said it intercepted 18 of 20 missiles. The existence of reciprocal hostile activity is well supported. The initiation sequence, tanker identities, damage and effects at Al Azraq are not.

The strongest opposing case is that this remains an open waterway under active protection. JD Vance claimed that flows had returned to approximately 15 million barrels per day, while Central Command reported that US forces had assisted nearly 1,500 vessels carrying about 750 million barrels since the conflict began. On 1 September, Central Command also reported escorting 40 commercial vessels carrying about 18 million barrels. The Finland Prosperity was observed carrying nearly 2 million barrels through Hormuz on 9 September, and QatarEnergy cargoes have continued to move through alternative arrangements. This evidence matters. It argues against describing the strait as physically sealed, and it shows that US naval power and commercial adaptation have preserved some energy movement. Nevertheless, the conclusion that Hormuz is open in any meaningful commercial sense does not follow. A selected tanker, an escorted convoy or an opaque shuttle arrangement demonstrates survivability, not normality; the relevant question is whether an unknown operator can schedule an ordinary voyage without exceptional political, insurance or force-protection assumptions.

Bab al-Mandab provides a useful comparison. Houthi forces reportedly attacked Saudi territory, fought around western Taiz and southern Hodeidah, and claimed to have seized Mokha and moved towards the Hanish Islands. Those territorial claims lack independent imagery or confirmation from a named third-party authority. Yet Bab al-Mandab traffic remained comparatively resilient: 28 commodity vessels were recorded on 9 September against a 10-day average of 27. The mechanism therefore differs from Hormuz. In the Red Sea, the principal risk is an elevated threat to selected routes, especially those associated with Saudi Arabia, while in Hormuz direct US-Iran exchanges are combining with sharply reduced observed traffic and uncertainty over maritime enforcement. The theatres converge in their commercial effect, because Maersk, MSC, Hapag-Lloyd, BP and Frontline have rerouted or avoided exposed waters. They diverge in operational condition: Bab al-Mandab remains active near its recent traffic level, whereas Hormuz is functioning through exception rather than routine.

The implications divide by actor. For Washington and Tehran, selective maritime pressure offers coercive leverage without requiring either side to announce a formal blockade, but it also creates a dangerous ambiguity over rules of engagement. Donald Trump has presented Iran as defeated while retaining the option of further strikes, including against strategic sites; the supplied record does not show a settled political end state. For Gulf governments, the immediate problem is not simply whether oil exists underground, but whether it can be loaded, insured and delivered. QatarEnergy extended force majeure into early November and cancelled 29 LNG cargoes, while Saudi Arabia has relied on Yanbu, the Sumed system and other routes to reduce exposure. For operators, the reported approach of Middle East to China supertanker earnings towards US$800,000 per day and US Gulf to Asia offers of US$29.5 million captures the mechanism more clearly than any official declaration. Risk has become a cost before it has become a shortage.

The evidence has material limits. Kpler's observations do not supply a complete AIS population, a consistent vessel category or a fully specified geographic boundary; the cited pre-conflict figures of 130 to 140 daily transits therefore cannot be treated as a like-for-like denominator. Rystad models flows, Vitol reports a company estimate, and UK Maritime Trade Operations relies substantially on mariner and operator notifications. Central Command and the IRGC report their own actions and claims, not an impartial account of the conflict. The names Kylo and Noxen may refer to the same vessel, while accounts disagree over locations, dates and the number of tankers damaged or destroyed. These limitations weaken confidence in attribution and total flow, but they do not erase the direction of travel. I would change the assessment if three consecutive days of independently matched vessel data showed traffic near the pre-conflict baseline, if LNG departures resumed at scale, and if insurers accepted a published navigation procedure. A verified 48-hour absence of authorised commercial passage, supported by independent port data and imagery, would move the judgement towards closure.

The central question, then, is not whether Iran has closed Hormuz. It is whether exporters, buyers and shipowners can still treat the strait as dependable infrastructure. The fortnight's answer is no. Hormuz is not strategically important because every vessel has been stopped, but because uncertainty has made every passage conditional; the waterway's power lies not in what it physically prevents, but in what it persuades others not to attempt.