• Brent rose 1.3% to $90.49 and WTI rose 2.8% to $85.76 on August 31, 2026, after CENTCOM said it struck Iranian forces on an island in the Strait of Hormuz and Iran retaliated against the UAE and Jordan, Rigzone reported.
• Iranian state media reported a supertanker hit by mines; CENTCOM said it fired on IRGC personnel preparing to lay mines and denied any vessel was struck — both claims are contested and unconfirmed.
• Hormuz flow has run far below its 2025 baseline of roughly 15 million barrels a day throughout the war: about 2.3 million b/d before a June 17 truce and about 6.1 million b/d during its 60-day run, per Al Jazeera's tanker-tracking; the EIA puts a fully normal flow near 21 million b/d.
• The war began in late February 2026; a June 17 memorandum of understanding lifted flows for 60 days but lapsed without a permanent peace deal, and shipping attacks continued even during the truce, per Al Jazeera.
• Monday's strikes are an escalation within a seven-month conflict, not a new war — WTI is already up roughly 50% year-to-date on the back of it, Rigzone reported.

Brent November futures rose 1.3% to $90.49 a barrel and WTI October futures gained 2.8% to $85.76 on August 31, 2026, Rigzone reported, after US Central Command (CENTCOM) said it struck Islamic Revolutionary Guard Corps (IRGC) forces on an island in the Strait of Hormuz and Iran retaliated against the United Arab Emirates (UAE) and Jordan. WTI is up roughly 50% year-to-date, a reminder this market has traded war risk, not calm fundamentals, since the conflict began in late February 2026. This is analysis of what moved the barrel and why — not advice.

What happened Monday

US forces struck an island in the Strait of Hormuz, targeting IRGC positions, CENTCOM said, and Iran responded with strikes on US-linked targets in the UAE and Jordan, Rigzone reported. CENTCOM said it also fired on IRGC personnel it accused of preparing to lay mines in the strait; Iranian state media reported an unidentified supertanker was struck by two mines, a claim CENTCOM denied. A US military commander had said the previous week that forces had quietly cleared Iranian mines from shipping lanes. None of Monday's battlefield claims are independently confirmed.

The flow numbers behind the rally

Hormuz throughput has run well below its pre-war level for months. Al Jazeera's tanker-tracking analysis put flow at about 2.3 million barrels a day between April and a June 17 truce, rising to roughly 6.1 million barrels a day — about 40% of 2025's level — during the truce's 60-day run. In 2025, before the war, the strait carried roughly 15 million barrels a day, per that same analysis; the EIA separately puts a fully normal Hormuz flow at about 21 million barrels a day, a fifth of global oil consumption. Every one of those figures sits well below capacity.

The truce that lapsed, not a fresh war

Monday's exchange is an escalation, not a new outbreak. The US and Israel opened this war on Iran in late February 2026, according to Al Jazeera. A June 17 memorandum of understanding, billed as a step toward a permanent end to the fighting, ran 60 days and lifted flows before lapsing without a follow-on peace deal. Attacks on shipping didn't fully stop even during the truce: Al Jazeera reported at least 18 seafarers killed since late February, five commercial vessels attacked in the week before August 20, and the tanker Minoan Dignity struck that same week, killing one seafarer — the first confirmed shipping death since July.

What to watch next

Three signals matter more than Monday's percentage move: whether the US claim of cleared mines holds, whether Iran escalates further against Gulf US allies beyond the UAE and Jordan, and whether a new truce is negotiated or transits keep falling — strait crossings were already down to 73 in the week of August 10-16 from 91 the week before, per Al Jazeera. Those shifts will show up in tanker-tracking and EIA flow data before they show up in a wire headline. Saxo Bank's Ole Hansen told Rigzone that traders are watching the barrels themselves, not the headlines, and will stay cautious as long as oil keeps moving through the strait. This is analysis of what moved and why, sized against the physical flow of barrels — not advice, and not a trading call.