80% of Iran's oil flows to China as US sanctions squeeze global supply

For energy and climate strategists, the squeeze on Iranian crude is a global supply shock in the making. With 80% of Iran's seaborne oil going to China and the Strait of Hormuz at a standstill, sanctions are redrawing energy trade flows and putting pressure on refiners, fuel prices and energy-security planning.

President Donald Trump has promised to hit Iran 'hard' economically, sharpening a campaign that Treasury Secretary Scott Bessent says will escalate as soon as next week with measures on Tehran that have 'never been seen.' Bessent is scheduled to detail the package at a 2 p.m. EDT press conference on Monday, August 24, 2026. The pledge, reported by Reuters on August 22, lands at a moment when the Strait of Hormuz is already at a virtual standstill and Iran's economy is buckling under a sanctions regime that has been building since the late 1970s.

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The United States, United Nations and European Union have layered sanctions, trade embargoes and asset freezes on Iran for decades over its nuclear program, human rights record and support for militant groups.

The United States, United Nations and European Union have layered sanctions, trade embargoes and asset freezes on Iran for decades over its nuclear program, human rights record and support for militant groups. Since the Iran war began in February 2026, Washington has added maritime, energy and financial sanctions and imposed a naval blockade. Treasury's Office of Foreign Assets Control has designated more than 1,000 people, vessels and aircraft since Trump's second term began, according to OFAC data — a sweeping expansion that has targeted Iran's shadow oil fleet, shipping insurers, weapons-procurement enablers and digital exchanges.

One of the most striking figures is the estimated $500 billion in Iran-linked cryptocurrency that recent measures have frozen, underscoring how digital assets have become a major sanctions-evasion channel that Washington is now moving to close. The freeze signals a shift in enforcement focus toward crypto exchanges and intermediaries, which had emerged as a workaround for traditional banking channels. On the maritime front, oil shipments are effectively halted in the Strait of Hormuz, with Tehran threatening to strike any unauthorized tanker transiting the vital waterway. The combination of a naval blockade, insurer designations and the shadow-fleet crackdown is squeezing the physical and financial plumbing of Iranian crude exports.

The most consequential lever still available is secondary sanctions on China's independent 'teapot' refineries. These refiners account for roughly a quarter of Chinese refinery capacity and operate on narrow, sometimes negative, margins. China buys more than 80% of Iran's shipped oil, according to 2025 data from analytics firm Kpler, and independent refiners absorb much of that trade — which exposes them to US secondary measures that penalize entities assisting a primary sanctions target. Experts cited in the reporting note that past US actions against Chinese entities offer a template for how Washington could escalate. Targeting teapots would pressure Beijing's refiners and, by extension, test the resilience of a trade relationship that has kept Iranian crude flowing despite Western pressure.