The Iran oil shock reaches U.S. inflation today — and slams the door on Fed rate cuts

A fragile Israel–Iran ceasefire pulled Brent back to $91, but a still-shut Strait of Hormuz has already pushed May CPI toward 4.2% — a third straight monthly acceleration.

The May U.S. consumer price index, due at 8:30 a.m. ET today, is set to print near 4.2% year-on-year — up from 3.8% in April and the highest since 2023 — confirming that the Iran war’s energy shock has reversed America’s disinflation. Markets meet the data with the Fed boxed in: a +172,000 May payroll surprise has already erased 2026 rate-cut hopes. The S&P 500 slipped 0.3% to 7,387 on Tuesday.

What happened. Headline inflation has climbed from a steady 2.4% in January–February to 3.3% in March and 3.8% in April, with energy alone up 17.9% year-on-year — over 40% of April’s monthly gain. A weekend exchange of Israeli and Iranian strikes briefly lifted Brent to $95 before the ceasefire pulled it back to $91.11 (-3.4%). But the Strait of Hormuz, which carries roughly a fifth of seaborne oil, stays under a de facto U.S.–Iran blockade, keeping a structural risk premium embedded in crude.

Why it matters. The growth-inflation mix has turned stagflationary: prices are accelerating while the energy tax saps demand. With payrolls firm and CPI above 4%, the Fed’s restrictive stance is locked in — the 10-year Treasury holds 4.54% and gold has unwound 1.3% to $4,260 as “higher-for-longer” real rates bite.

The China angle. The offshore yuan has firmed to ~6.78, its strongest since February 2023, as Chinese assets draw a relative safe-haven bid. For firms going global, Hormuz is the live exposure: roughly half of China’s crude transits the strait. Belt & Road energy logistics and supply-chain rerouting shift from contingency to necessity.