SHANGHAI—The coronavirus pandemic is making the “decoupling” of the U.S. and Chinese economies a more realistic prospect, American companies in China say, as it disrupts supply chains and further strains relations between the two countries.

In March, 44% of 25 large U.S. companies surveyed said decoupling would be impossible, down from 66% in October, the American Chamber of Commerce in China and the American Chamber of Commerce in Shanghai said.

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