U.S. military says it aided passage of 660 million barrels of oil through Strait of Hormuz since May

The U.S. military has helped tankers transport more than 660 million barrels of crude oil through the Strait of Hormuz since early May, Central Command told CNBC this week.

The military has assisted about 1,300 commercial vessels sail through Hormuz over the same period, said U.S. Navy Capt. Tim Hawkins, a Central Command spokesperson, in a statement Thursday.

"Multiple routes remain free and open for commercial transit," Hawkins said.

This suggests at least 160 million barrels, or more than 7 million barrels per day, have transited the strait over the past three weeks, based on the military's past statements. Central Command said on July 29 that U.S. forces had assisted 500 million barrels through Hormuz since May.

The shipments are still far below the fuel exports before the war, when about 20 million bpd of crude oil and products passed through Hormuz. But the U.S. military's figures indicate that a substantial amount of oil is passing through the strait despite Iranian threats and attacks.

Exactly how much oil is coming out of Hormuz daily is unclear as the U.S. government has provided different estimates that are usually higher than data from independent ship tracking firms.

U.S. officials told Axios Wednesday that about 10 million bpd have exited the strait in recent weeks. Energy Secretary Chris Wright said Aug. 11 that the seven-day average had risen to nearly 9 million bpd.

Private monitors are giving other estimates.

The maritime intelligence firm Windward estimates that crude oil exports through Hormuz averaged about 5 million bpd in July, compared with about 4 million bpd in June and 1.6 million bpd in May.

Exports in August are expected to increase over July as well, said Michelle Wiese Bockmann, senior maritime intelligence analyst at Windward.

"My assessment is that it's scaling and it's scaling quickly despite the fact that Iran is placing enormous pressure on maritime security," Bockmann said.

"The Gulf states have got U.S military protection — that's not a secret," the analyst said. They are "ready to do whatever they can" to increase their oil exports through the strait, she said.

There's a lack of solid information on exactly how much oil is moving through Hormuz due to the complexity of tracking ships during wartime, said Bridget Diakun, maritime intelligence and research director at Lloyd's List.

Ships often transit at night but satellite imagery is usually taken in the morning, Diakun said. "There's a lot of unknowns," she said at a Thursday briefing.

The U.S. energy secretary said last week that "many private businesses undercount the number of ships leaving the Strait of Hormuz due to ships moving covertly through the waterway."

"In coordination with the U.S. military, the U.S. Department of Energy maintains the best available data related to oil and oil products leaving the Arabian gulf," Wright said in a social media post.

Contested control

The security situation in Hormuz remains contested. Iran said Tuesday it has closed the strait until the U.S. meets its obligations under the interim peace deal signed June 17. President Donald Trump, meanwhile, has insisted the strait is open and under U.S. control.

Hormuz has been divided between two different shipping lanes for months. The U.S. military assists ships that use a southern route along Oman's coast. It has also imposed a naval blockade against Iranian ports. Tehran demands that vessels use a northern route through its territorial waters or risk attack.

"It's a contested security situation in the Strait of Hormuz," said Jakob Larsen, chief safety and security officer at BIMCO, one of the biggest shipping trade associations in the world.

The strait is 21 miles wide at its narrowest point. The U.S. has more control closer to Oman and Iran has more control closer to its coastline, Larsen said.

"But both sides are still able to project power on either side of the strait," he said. "It's not really possible for either side to completely defend their own interests in the territorial waters of Oman and the territorial waters of Iran."

At least 17 commercials ships came under attack in and around the strait in July and August, according to the International Maritime Organization, a United Nations agency. At least four sailors died in those attacks and more than a dozen suffered injuries.

But tankers that make the journey earn $500,000 a day, Bockmann, the analyst at Windward, said. Seafarers receive double or triple their pay to make those transits, she said.

"It's a very intense, serious operation to get the oil out — high risk, high profit," Bockmann said.