The blockade reroutes oil, and the constraint moves into insurance policies

The noise is zero barrels, the signal is the physical premium

The headline number is zero. According to satellite tracking reported by Briefs on 1 October, Iran loaded not a single barrel of crude in September under the US blockade. Three separate trackers, from Bloomberg, Kpler and Vortexa, reached the same result; August loadings had run at about 250,000 barrels a day. In the eighth month of a war that began in February, Iranian shipments stopped completely for the first time.

The market did not lose those 250,000 barrels; it recovered them from other ports. Kpler data cited by Gulf News show regional crude exports excluding Iran rising to 19.5 million barrels a day in the last week of September. The pre-war level was 17 million barrels, so volumes appear to have overshot it by 2.5 million barrels.

Prices tell a different story. According to Oilprice's analysis of 2 October, Dated Brent, which prices physical cargoes, rose above $120 while ICE Brent futures stayed near $101. Dated Brent is the price of real cargoes loading within the next 10 to 30 days; a futures contract is forward paper delivery. The gap of roughly $19 shows that the barrels exist but delivering them has become expensive. According to The National, the front-month contract closed 2 October at $102.25, while WTI fell 1.9% to $91.11.

The constraint has moved from the strait to the policy

The only flow that physically fell to zero in September was Iran's, which had run at 250,000 barrels a day in August. According to The National, Saudi shipments through Hormuz rose from about 1 million barrels a day in August to 2.9 million in September. That recovery is only partial, since the pre-war level in February was 7.3 million barrels a day. According to Gulf News, about 40% of the region's crude now bypasses the strait, against 17% before the war.

Iraq took another route on 3 October. According to Asharq Al-Awsat, the state-owned Iraqi Oil Tankers Company moved 2 million barrels through Hormuz on its own VLCC, or very large crude carrier. The company described it as the first such operation in decades, and the transit relied on permission Iraq had obtained from Iran in advance. Tehran could not sell a single barrel of its own in September, but it still decides which flags pass through the strait.

Insurance is the constraint's new address. According to an Insurance Business report of 2 September, war-risk premiums ran at 0.15–0.25% of hull value before the war and rose to 3–10% after 28 February. A war-risk premium is the additional per-voyage insurance cost for a ship entering a conflict zone. On a $150 million tanker, 10% means $15 million for a single voyage. According to the same report, OFAC, the US Treasury's sanctions office, issued advisories naming three Iranian entities on 24 August. Insurers now use model clauses that void cover if a transit fee is paid to a sanctioned entity. Brokers run two separate compliance checks on every voyage.

The same shift is under way in Russia's shadow fleet. This is a network of tankers, averaging 19 years old, that carries sanctioned oil under weakly supervised or false flags. According to Lloyd's List, Russia has moved 86 tankers from that fleet onto its own flag since July, most of them from the Cameroon, Sierra Leone and Equatorial Guinea registries. CREA data cited by Bluewin show falsely flagged Russian shadow fleet vessels falling from 101 to 45 between October 2025 and June 2026. Over the same period the Russian registry grew 36% to 382 ships.

According to Newsweek, the EU has sanctioned more than 670 shadow fleet vessels, yet none of the six ships boarded by EU operations in recent months was seized. A valid Russian flag makes boarding legally harder. What remains is the insurance certificate, port access and the flag state that carries liability for accidents involving a 19-year-old fleet. In Hormuz as in the Baltic, sanctions enforcement in 2026 is shifting from seizure to the policy and flag-state liability.

The critical thresholds in numbers

The first threshold lies at Iran's wellheads, and the number is 1.8 million barrels. According to Gulf News, with storage full Iran may have to cut output to about 1.8 million barrels a day, barely enough to meet domestic consumption. This is an estimate and could not be verified against official data. If well shut-ins begin, exports would struggle to return quickly to August's 250,000 barrels even if the blockade eased.

The second threshold is whether Hormuz stays insurable. Saudi shipments exceeding half of February's 7.3 million barrel level, or 3.65 million barrels a day, would be the first concrete evidence that the strait remains commercially insurable. The third is the physical premium. A narrowing of the $19 gap between Dated Brent and futures to below $10 would show the delivery constraint easing.

OPEC+ is a secondary factor. Seven core members are discussing November quotas online today, 4 October, and no outcome had been announced as this report was written. Oilprice reports that quotas are expected to stay unchanged. Core producers pumped 25 million barrels a day in August, about 5 million below pre-war levels. With actual output 5 million barrels below quota, the decision shapes the bargaining over 2027 baseline quotas rather than supply.

The fourth threshold is Europe's gas buffer. According to EnergyRiskIQ, EU storage was 72.3% full on 3 October against a five-year seasonal norm of 92.0%, a gap of 19.7 points or about 216,700 GWh. Reaching 90% by 1 November requires injections of 6,714 GWh a day; the current pace of 2,724 GWh is about 41% of that. According to Global Energy Flow, the relaxed target for 2026 is 80%, and at the 14-day pace storage reaches only 78.1% on 1 November. The same source says the closure of Hormuz on 28 February pulled Middle Eastern LNG away from Europe. The gas shortfall, in other words, is another bill from the same strait.

Second-round effects and Türkiye

The cost of redistribution accumulates in delivery rather than volume: a $19 physical premium is loaded onto every cargo that reaches a refinery. That premium makes the relatively calm futures level of $102.25 on 2 October misleading.

Türkiye is the last link in this chain. According to AA, its energy import bill rose 33.8% in August to $6.464 billion. A year earlier the bill was about $4.83 billion. In the same month crude imports fell 1.1% by volume to about 2.84 million tonnes. The bill swelled through price, not volume, and the $19 physical cargo premium passes into the external balance through the same channel. Europe's 19.7-point storage gap is intensifying competition for winter LNG cargoes, and Türkiye is one of the importers bidding for them.

What would refute this reading

Our thesis is that the blockade redistributes supply rather than destroying it, and that the constraint is shifting into the insurance policy. We see this as the most likely path, with a 55% probability. If regional exports fall below 17 million barrels a day in October and the loss comes from a source other than Iran, the redistribution thesis collapses. If the gap between Dated Brent and futures stays below $5 for two weeks, the claim that the constraint sits in the policy weakens.

If the EU or the UK seizes a Russian-flagged tanker before the end of 2026, the reading that reflagging provides protection is disproved. According to Reuters, Saudi authorities have not confirmed the Houthi claim of a 3 October strike on an Aramco facility in Riyadh. If Aramco announces a production or loading disruption, the constraint becomes physical again and the probability of scenario H2 rises.