Major Chinese and Hong Kong shipping groups logged record revenue and profit growth in the first half of the year, buoyed by a confluence of factors driving up international freight rates.

State-owned COSCO Shipping Holdings, the world’s third-largest maritime carrier by capacity, said first-half revenue grew 88% on year to 139.26 billion yuan ($21.5 billion) while net profits soared by a factor of 32 to reach 37.09 billion yuan.

During the first six months of 2021, the company’s container fleet handled 13.84 million TEUs, or twenty-foot equivalent units, a 16.8% increase from a year before.

But the driving force for COSCO’s earnings surge was price growth, not higher volumes.

The China Containerized Freight Index averaged 2,066.64 points during the first six months of the year, up 133.9% from a year ago and 92.4% higher than the second half of 2020. The Baltic Dry Index, a global indicator for bulk freight rates, stood at 4,132 points on Wednesday, near an 11-year high.

Xu Lirong, chairman of Orient Overseas (International), a Hong Kong-listed unit of COSCO, attributed the historic price rises to “port congestion, bad weather delays, labor disputes, shortages of truckers, the Suez Canal incident, insufficient rail capacity, empty-box shortages in key locations, quarantine/social distancing in terminals, depots, yards and for vessel crew, and a range of other difficulties” in his company’s earnings report.

The carrier, better known under its operating brand OOCL, saw first-half revenue more than double to $6.98 billion while net profit surged by a factor of 28 to $2.81 billion.

The benefits of higher rates have been shared throughout the industry.

A.P. Moller-Maersk, the top global rival for COSCO, reported a 44% rise in revenue to $26.66 billion while its net profit grew almost tenfold to $6.4 billion during the first six months of 2021.

Port operators enjoyed major gains, too.

COSCO Shipping Ports, a conglomerate unit that manages 357 berths at 36 ports globally, boosted revenue 25% to $564.9 million for the January-June half, benefiting from port congestion. President Zhang Dayu told reporters on Thursday that although storage fees make up a small part of the group’s income, such fees “in several of our ports grew by double digits, and some of them more than doubled.”

Logistics service providers got their cut as well. Kerry Logistics Network’s revenue grew 68% to 36.7 billion Hong Kong dollars ($4.71 billion) while its bottom line more than tripled to HK$3.38 billion.

“We are seeing ports all over the world having lockdowns and congestion,” Vic Cheung, executive director of the Hong Kong-based player, said in an online press briefing last week.

When the target ports are closed or clogged, “we would divert to other ports — wherever the nearest ports — to ship it out,” he said. “The reality is that we continue seeing challenges both at origins and destinations.”

This adds traffic for service providers such as China’s state-owned Sinotrans, which reported remarkable half-year results as revenue jumped 55% to 61.67 billion yuan and net profit rose 78% to 2.16 billion yuan.

Rail operators also benefited in the half, though with less dramatic gains. Guangshen Railway’s revenue rose 30% to 9.66 billion yuan, and net profit hit 4.27 million yuan after a net loss of 613.98 million yuan a year ago. Passenger through service connecting Hong Kong and mainland cities was shut due to the pandemic, but intercity and long-distance passenger trains recovered, while cargo transport gave another boost.

In its interim report published Monday, Guangshen said it “made full use of the transportation resources unused because of the decrease in passenger volume.” Under the strategy of “replenishing customers with goods,” the operator converted passenger trains to cargo and increased freight revenue by 35% to nearly 1 billion yuan.

By contrast, the aviation sector has been largely left behind. All three big state-owned carriers — China Southern Airlines, Air China and China Eastern Airlines — continued to lose money in the first half of 2021, despite gains in cargo. Their aggregate net loss totaled 16.67 billion yuan, about 10 billion yuan less than last year.

They trailed smaller peers Spring Airlines and Juneyao Airlines, which returned to net profit during the first half, while small regional carrier China Express Airlines lifted its bottom line by 42% to 11.65 million yuan.

But the surface transport sector sees worrying signs.

“Port congestion is becoming a bigger problem, especially in the U.S.,” said Andrew Lee, analyst at Jefferies. With the peak season for trans-Pacific routes coming in autumn for the North American holidays, “we expect the supply bottleneck to worsen before improving, which also places vessel supply pressures on other routes given longer journey times, reducing effective supply.”

Chairman Deng Renjie of state-owned China Merchants Port Holdings, which manages 50 ports in 26 markets, told reporters Monday that “on top of the pandemic, the second half of the year is a traditional peak transport season, and the challenge is there.”

Deng also indicated the difficulty in maintaining growth, as the industry’s recovery started a year ago. “The base figure for last year is quite high,” he said.