When the first two rounds of 10% tariffs hit, Zou Guoqing, a Chinese exporter, groaned but didn’t find the barriers insurmountable. He gave up some of his profits and offered his client, a snow-bike factory in Nebraska, price cuts ranging from 5% to 10%. It seemed to work: The factory agreed to a new order of molds and parts.

But when President Donald Trump announced an additional 34% universal tariff on Chinese goods on April 2, Zou, who’s been exporting to the U.S. for more than a decade, was incredulous.

“There’s not a thread of feasibility,” said Zou, who does business in the eastern Chinese city of Ningbo. “It looks like I would have no choice but give up trading with the U.S.”

Then came 50% more from Trump, followed by another hike — pushing the universal tariff on Chinese goods to the sky-high 145%, and Zou said he now could only hope that the two leaders can communicate. “We are pausing the shipments,” he said, “until the leaders talk.”

The 145% tariff from the United States and the retaliatory 125% tariff from China are putting businesses doing trade between the U.S. and China on edge. They’re fretting not only about their next orders, but also the viability of their business if there’s no quick relief. Experts are worried the decades-long trade ties that have underpinned the relationship between the world’s two largest economies could be unraveling.