Brent crude closed above $100 a barrel on 9 September 2026 for the first time since late July, as the United States tightened its naval blockade of Iran and traffic through the Strait of Hormuz fell to a fraction of its pre-war volume. The benchmark rose more than five per cent on 10 September to about $106.
The blockade’s current phase began on 13 July on the order of President Donald Trump. US Central Command has reported redirecting vessels in rising numbers through early September, passing the hundred-vessel mark on 12 September. The command says no ship has passed without US permission; Iran’s Khatam al-Anbiya headquarters has said the opposite, that no tanker can transit safely without Iranian permission. Both claims are stated by the parties making them.
On 8 September the US Treasury sanctioned 36 targets under a campaign it calls Operation Economic Outcast, including 27 Iranian airlines and aviation-support companies registered in the United Arab Emirates, the United Kingdom, Türkiye, Malaysia and Kazakhstan. The Treasury alleges the network diverted at least three Boeing 777 aircraft to Mahan Air during the summer.
The supply effect is the part that travels. Hormuz carried roughly a fifth of the world’s oil and gas before the war. Flows through the strait fell from eight to nine million barrels a day in late August to below two million. The International Energy Agency has forecast a decline in global oil supply of about 4.3 million barrels a day for the year, and Morgan Stanley expects Brent to average $100 in the fourth quarter.
Iran has said it will discuss safe commercial shipping routes at a regional meeting in Oman on 14 September. Bahrain has declined to attend. On 12 September the Iranian foreign ministry restated its conditions for reopening the strait: an end to the war, the lifting of the naval blockade and sanctions, the release of frozen assets, and compensation for war damage.
