Hormuz attacks doubled in October. Why did Brent's average rise just 4.4%?
The IMO confirmed 30 ship incidents in October's first 23 days, double September's 15. Brent's average close rose 4.4% as traders weighed US strike odds and the Tehran talks. War risk cover adds under a tenth of the price rise since February.
Hormuz ship attacks doubled in October, yet Brent's average close rose only 4.4%. It went from 102.3 in September to 106.8 through 26 October, on Yahoo Finance data. End to end, from 103.53 on 30 September to 115.81 on 26 October, the rise is 11.9%.
Brent's price reflects the odds of a US or Israeli strike on Iran and of a deal in Tehran, rather than each ship attack. Both price moves are small beside a doubled attack count, so the count alone is a poor guide to oil.
Iran's navy said on Tuesday that an oil tanker caught fire after hitting naval mines east of the Strait of Hormuz, Anadolu reports. Brent fell anyway. It was down 0.9% at $114.81 a barrel by 1311 GMT on Tuesday, Reuters data show.
Iran makes mine claims often. Iranian forces made similar statements on 20, 22 and 23 October, the last an IRNA report of two supertankers disabled by sea mines. The ship reports describe other causes.
Attacks rose faster than oil prices
The International Maritime Organization (IMO) keeps the independent record of confirmed incidents. It stood at 121 incidents and 24 seafarer deaths on 27 October.
October is the worst month on that list. Counted by incident date, March had 20, then 9, 12, 8, 14, 13 and 15 in the months to September. October has 30 in 23 days, twice September's total.
Hormuz itself is busier too. Rows the IMO places in the Strait of Hormuz rose from 8 in September to 14 in October. Reuters reports that October was the worst month for attacks on shipping near Hormuz in a data set that starts in 2017.
The price rise was far smaller than the count. Brent futures closed at 113.17 on 22 October, up 4.0%. They closed at 116.72 on 23 October, up 3.1%, after Trump said the US may strike Iran again.
Brent is up 16% from 100.32 on 5 October to that 23 October close. The month's average still rose only 4.4%.
Talks pull the price back down. Iranian officials said Tehran has plans to attack Gulf undersea cables if the US and Israel strike again. On Monday the price slipped 0.8%, the day Saudi, Turkish and Pakistani officials met Iranian officials in Tehran. On Tuesday it fell again.
What the shipping reports say
The ship reports do not mention mines. The UK Maritime Trade Operations centre (UKMTO) published 40 reports between 29 September and 26 October. Thirty cite an unknown projectile, one a drone and one a rocket propelled grenade, and none a mine. The centre reclassified one tanker incident as an attack after confirmation that an uncrewed aerial vehicle had struck it.
The loss of the bulk carrier Cape Dao points the same way. Lloyd's List reports that it sank east of Sohar on 14 October after two torpedoes struck it the month before, killing one seafarer.
Iran has added ships to its blacklist after attacks. Its Persian Gulf Strait Authority keeps a blacklist of ships, which it expanded to 124 vessels on 16 October. Cape Dao was added only after it was hit.
Traders are pricing the risk of another strike. SEB sees "a significant risk premium in crude oil prices for the risk that the US/Israel will attack Iran in the coming weeks". UBS expects Brent near $110 at year end, up from $100.
A deal is the other side of the trade. A Pakistani official told Reuters that the army chief presented Iran with a solution, with Mecca pact states and Qatar as possible guarantors.
How supply and insurance affect the price
Convoys, bypass routes and stock draws have absorbed much of the lost supply. The EIA puts Hormuz flows of total liquids at 4.9 million barrels a day in the second quarter of 2026. That is down 77% from 21.6 million in the fourth quarter of 2025.
US strategic stocks fell from 413 million barrels to 321 million over the same period. Supply risk stays live. Houthi forces say they hit Saudi Arabia's Ras Tanura refinery on Tuesday, and OPEC+ is expected to hold December output targets on 1 November.
Insurance is a smaller part of the bill. Al Jazeera reports S&P Global's July finding. Hormuz war risk cover rose from 1 to 3% of hull value to 7.5 to 10%. An insurance analyst said cover was still available, "often on restrictive terms".
Lloyd's List counts 73 Sinokor supertanker purchases, valued at over $6 billion, so a ship is worth about $82 million. A 7.5 to 10% rate on that hull is $6.2 million to $8.2 million a voyage, the usual basis.
On a two million barrel cargo that is $3.08 to $4.10 a barrel. Brent's 26 October close of $115.81 is $43.33 above its 27 February close of $72.48, so cover is 7% to 9.5% of the rise. The hull value and per voyage basis are CTOL arithmetic.
Freight costs more than insurance and moves with perceived risk, not the incident count. The Oman to China supertanker rate index is up 141% since 1 September. It is down 34% from its record on 8 October, even as attacks doubled.
Sinokor owns those 73 tankers, so it carries the risk first. Its ships made up 47% of September supertanker transits and over half in the first ten days of October. Seven of its tankers had been hit by 21 October. The blacklist authority said on Tuesday it took enforcement actions on seven Sinokor vessels.
What fuel buyers face next
The buyers of fuel pay next. France is due to start releasing 10 million barrels of diesel from reserves on 1 November. Qatar has extended force majeure on LNG cargoes to Italy's Edison to the end of December.
A refiner or airline pricing first quarter 2027 cover must choose between locking in now and waiting for Tehran. The EIA's October baseline has Brent at $84 for 2027. Waiting leaves the buyer open to the strike that SEB says is priced as a risk premium.
A shipowner weighing a Gulf voyage faces a smaller question. Cover costs $3 to $4 a barrel against a freight index up 141% since 1 September.
On 10 November the EIA publishes its November outlook. On futures prices, its $105 fourth quarter Brent spot assumption needs November and December to average about $104. The October average is 106.8. Unless a Tehran deal brings Brent under that line, the agency is likely to raise the number.