Tehran's oil export troubled just got worse. 

One week after we reported that Iran was already struggling to sell its crude to buyers in Asia (including China, which appears to now prefer UAE exports instead), overnight the US rescinded the sanctions waiver that allowed Tehran to sell its oil without penalties, making sales of Iranian crude to international buyers even more challenging. 

The Iranian attacks on three commercial vessels in the Strait of Hormuz on Tuesday prompted immediate US reaction with the USmilitary striking multiple targets in Iran and the Treasury canceling the waiver on Iran’s oil sales that was supposed to be in place until August 21.

Iran’s oil sales could be constrained again even before they resume, OilPrice reports. Since the memorandum of understanding was signed in mid-June, Iran has rushed to load cargoes from its key export sites at Kharg Island, and move its tankers out of the Gulf as soon as possible, after weeks of virtually no exports because of the U.S. blockade that began in mid-April.

The surge in Iranian shipments out of the Gulf and into waters near the Malacca and Singapore Straits gave Iran a lifeline to boost its exports that had suffered from the U.S. blockade.

China has remained Iran’s key customer as other buyers are reluctant to commit to purchases. But in recent weeks, we learned that even Chinese purchases of Iran oil have slowed dramatically, and now that the US has ended the waiver and sanctions are in place again, buyers in India that were considering potential purchases have likely backed out. 

Additionally, one could go so far as to argue Iranian oil in tankers is once again subject to US seizure.

Iran is thus left with millions of barrels of crude oil on tankers moving or idling in a large area from the Persian Gulf to the Strait of Malacca. Most of the laden tankers do not broadcast destination or broadcast they are for orders, according to vessel-tracking data compiled by Bloomberg.

Currently, as many as 63 million barrels of Iranian oil are either in transit or idling in tankers, per Bloomberg’s estimates based on data from Vortexa, which also notes that oil on floating storage in the Gulf has more than doubled in the past week to over 41 million barrels.

“Iran managed to ship out 60 million barrels of crude oil since the US Navy blockade paused in mid-June 2026,” TankerTrackers.com said late on Tuesday, after the U.S.-Iran tensions escalated again.

“If the blockade were to resume now due to escalating tensions, Iran would be stuck with ~50 million barrels of crude oil and refined products.”