Hormuz has stopped being an episodic risk, and marine insurance should stop pricing it as one

The Islamic Revolutionary Guard Corps has fired toward the Strait of Hormuz again, the latest in a run of actions against commercial shipping that has accumulated through 2026 ^[1]. The question for anyone moving barrels or writing cover on hulls is no longer whether each event counts as a warning shot or an attack, but whether Hormuz transit can still be underwritten as a normal route that occasionally spikes.

The dated record, as reported by Crypto Briefing citing The Week, runs like this. On April 18, gunboats linked to the IRGC fired on at least three commercial vessels, incidents documented by United Kingdom Maritime Trade Operations ^[2]. On May 28, the IRGC fired warning shots at four ships attempting what Iran called unauthorised passage ^[3]. Then on July 21 and July 30, two oil tankers either reversed course or caught fire after explosions linked to IRGC activity ^[4]. That is four dated episodes involving at least nine vessels ^[5] across a 103-day window ^[6], with the last two arriving nine days apart ^[7]. Crypto Briefing's own read is that the late-July pairing suggests incident frequency is rising ^[8].

The diplomatic track has moved the other way. A memorandum of understanding on safe passage reached between Iran and the United States in June collapsed without taking hold ^[9] - which places it squarely between the May and July incidents ^[10]. Relations have deteriorated since, and Iran has said the strait will not fully reopen without changes in US behaviour ^[11]. Earlier IRGC talk of temporarily closing the strait was widely treated as posturing, and each incident makes that reading marginally harder to hold ^[12].

The exposure is not marginal. Somewhere between 20 and 25 per cent of the world's seaborne oil trade passes through the strait ^[13], carrying crude from Saudi Arabia, Iraq, Kuwait, the UAE and Iran itself to Asia and beyond ^[14]. War-risk premiums on Gulf transits have a long history of spiking on exactly this kind of news, and insurance costs pass straight into the cost of moving oil ^[15].

The important detail is what a spike assumes. A spike is a deviation from a baseline that is expected to reassert itself. What the 2026 record describes instead is a condition: a documented cadence of interdiction, a failed bilateral mechanism ^[9], and a stated political precondition for normalisation that sits outside the control of any shipowner ^[11]. Cover priced as an event risk and routing modelled on an occasional detour both embed an assumption of reversion that the material here does not support. Charterers who have not stress-tested a full-year premium at elevated levels, rather than a two-week one, are carrying the difference themselves.

Three things to watch. Whether Western navies revive convoy escorts, which the US and allies deployed in the Gulf during the Tanker War of the 1980s ^[16] - a return to that posture would be an admission that the risk is standing, not passing. Whether Iran's stated condition of US behavioural change moves at all, since it puts the burden on diplomacy rather than deterrence ^[17]. And the tail case: a single incident that sinks a large crude carrier or draws direct fire from a Western navy, which by Crypto Briefing's assessment would convert a persistent background risk into an acute market event ^[18].