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The price of shipping a container from China to the United States has risen dramatically in the last year due to uncertainty surrounding trade tensions between Washington and Beijing. That's because Chinese exporters have been rushing to get goods to U.S. ports before new tariffs kick in, but data are suggesting that trend may soon run out of steam. China and the U.S., the world's two largest economies, have been locked in a tit-for-tat tariff fight over the last year, levying duties on each other's imports worth hundreds of billions of dollars in the last few months. Increasingly strong fears of an all-out trade war have inspired exporters to push forward shipment dates — a phenomenon called front-loading.

In fact, freight prices for containers going from China to the U.S. have surged more than 100 percent from a year ago as of the beginning of December, according to data from Freightos, an online freight marketplace, "Transpacific ocean freight peak season has been a bonanza, with prices still more than double last year," said a report on the most recent Freightos data published on the Baltic Exchange's news website. That was as freight rates for China to the U.S. West Coast jumped 128 percent while those from China to the U.S. East Coast surged 123 percent compared to the same period a year ago.

In contrast, China to North Europe freight rates were up just 11 percent in the same period due to pre-Christmas cargoes. In fact, even before a September announcement that tariffs will be hiked, many importers were already stocking up as front-loading boosted the Chinese export machinery. "Many importers from China front-loaded in advance of the 1 January scheduled increase to the 10% trade tariff. That boosted transpacific peak pricing, but there is a limit as to how much front-loading you can, or should, do," Zvi Schreiber, CEO at Freightos, said in a statement cited by the Baltic Exchange's site.

Changing trade routes

American tariffs on $200 billion of Chinese imports were set to rise sharply on Jan. 1, but those have since been put on hold following U.S. President Donald Trump and Chinese President Xi Jinping's recent meeting at the G-20 in Argentina. There, they agreed to a 90-day ceasefire on tariff escalations while the two sides continued to negotiate a potential agreement. However, analysts and markets are skeptical about a lasting truce given the back-and-forth between the two economic powerhouses. "The irony is that after ... Trump has turned up the rhetoric, the United States has started importing even more from China," said Soren Skou, CEO of Maersk, the world's largest container shipper by capacity, according to a November Reuters report. Maersk's data indicated China's shipments to the U.S. had grown 5 to 10 percent in the third quarter compared to the prior year as retailers built up their inventories to avoid any new levies, Skou said, according to Reuters. Supply chain management departments in a range of industries have been on their toes for months.

Exporters and logistics executives have confirmed the shifting of trade routes as factories rush to fulfill orders before a tariff hike. The U.S.-China tariff battle is even affecting the air cargo industry: Recently, the president and CEO of airport ground-handler and catering solutions provider SATS told CNBC his company has seen changes in routes due to the trade war.

Chinese data show slowing growth