Large quantities of Iranian oil are accumulating at sea, as Tehran struggles to find buyers before the 60-day deadline granted by Washington expires.

The amount of Iranian crude and condensate on tankers at sea exceeded 58 million barrels as of July 1, according to data from Vortexa and Bloomberg calculations. More than 90% of these shipments still have no specified destination.

Tankers are listed either as "awaiting instructions" or with Singapore as the next port of call, indicating possible ship-to-ship transfers in the Malacca Strait.

Failure to sell these shipments quickly could deprive Tehran of much-needed revenue and may weaken its negotiating position with Washington.

The Islamic Republic has until mid-August to find buyers, after the United States lifted sanctions on Iranian oil in mid-June and ended the blockade of Iranian ports as part of an interim peace agreement.

Demand from independent Chinese refineries—which were the main buyers of Iranian oil before the conflict erupted—remained weak, after their operating rates fell to the lowest in nine years.

Chinese state-owned refineries have also refrained from entering the market, citing concerns about banks' ability to finance any deals.

Where are the stranded Iranian oil shipments concentrated?

Most of these shipments are concentrated in or around the Persian Gulf, the Indian Ocean, or the Malacca Strait near Singapore. Iran said on Wednesday that it has shipped more than 40 million barrels of oil since the United States lifted its naval blockade.

But more than 20 million barrels of Iranian crude remained stuck in Asian waters for seven days or more, up nearly 18% from the previous week, according to Kpler data. Tehran faces a number of obstacles in its efforts to market these oil shipments.

Restrictions imposed by the European Union and the United Kingdom remain in place, complicating insurance procedures for shipments, while some ports may hesitate to receive tankers from the "shadow fleet" that Iran uses to transport its crude.

There is also the possibility that shipments could be disrupted mid-deal if President Donald Trump decides to end the granted period before its deadline.

Buyers' fear of reimposed sanctions on Iran

Buyers remain fearful that Washington could reimpose sanctions if negotiations collapse, according to US Treasury Secretary Scott Bessent, who told Fox News on Tuesday. Bessent stated: "No one other than China has bought this oil, and China was buying it even when it was under sanctions, so it still trades at a discount."

Another major obstacle for Iran to offload its crude is weak demand in major Asian markets, as interest remains limited despite Tehran's attempts to attract buyers.

The region also has ample supplies, both from non-Iranian Gulf oil that can now transit the Strait of Hormuz and from crude shipments from farther afield purchased during the war period.

China's imports of Iranian crude fell by more than half in June from the previous month to about 654,000 barrels per day, according to Kpler data. However, at least one tanker discharged a cargo of Iranian oil in China in the past week, according to Kpler and Vortexa data.

India's stance on importing Iranian oil

Indian Oil Minister Hardeep Puri met his Iranian counterpart in New Delhi last week but refrained from making a commitment to resume imports.

Indian state-owned refiners are currently avoiding buying Iranian oil, having already secured their crude supplies through at least the end of August, according to people familiar with the matter who asked not to be identified as the discussions are private.

These companies are still waiting for clarifications from Washington on the mechanism for executing US dollar-denominated payments, the people added. They indicated that India may consider resuming purchases of Iranian oil once the payment mechanisms are clear, while full lifting of sanctions could allow refiners to resume imports from Iran in the long term.

Asian demand for Iranian oil

However, quick Asian interest in Iranian oil may materialize if prices are at appropriate levels. Refineries that have already secured their crude supplies could resell part of their shipments to make room for Iranian oil if offered at steep discounts, and they could also raise operating rates if raw material costs decline.