In the sweeping decision, the three-member WTO panel found against China on nearly every point of contention with the U.S., the 27-nation EU and Canada. The panel found that Chinese measures "accord imported auto parts less favorable treatment than like domestic auto parts" or "subject imported auto parts to an internal charge in excess of that applied to like domestic auto parts."

The three trade powers argued that the tariff was discouraging automakers from using imported car parts for the vehicles they assemble in China. As a result, car parts companies had an incentive to shift production to China, costing Americans, Canadians and Europeans their jobs, they said.