Iran Military Threatens Hormuz Blockade for Nations Joining U.S. Sanctions; Oil Market on Edge

Iran's military issued an explicit warning on May 10, 2026 that vessels from countries joining U.S. sanctions against Iran would be barred from transiting the Strait of Hormuz. Iranian Army spokesperson Mohammad Akraminya told state-run IRNA: "From now on, countries that follow the American precedent in imposing sanctions on Iran will certainly face difficulties transiting the Strait of Hormuz."

The Strait of Hormuz handles roughly 20% of global daily oil supply. Iran has maintained a military blockade since the war began, causing estimated cumulative supply losses approaching one billion barrels. Brent crude closed Friday at $101.29 per barrel — up 95% during Q1 and 67% year-to-date. WTI settled at $95.42 per barrel.

The U.S. recently designated 11 entities and three individuals in the Middle East and China for assisting Iran in sanctions evasion. Friday also saw Iran launch missiles at the UAE again, while the U.S. Navy sank two Iranian tankers attempting to evade the cordon. HMM's container vessel Namwoo (011200.KS) was simultaneously struck by an unidentified projectile in the strait, prompting South Korea's emergency NSC meeting — Iranian responsibility not officially confirmed.

Key market watch points: whether G7 nations broaden sanctions participation, Saudi Aramco's East-West Pipeline (7.0 million bpd max) capacity to compensate for further shocks, and whether Brent breaks the $110 resistance level. Airlines, petrochemicals, and refining margins face accelerating pressure.

Not investment advice. Verify all figures with primary sources before acting.