A Bloomberg Economics study warns that former President Donald Trump’s plan to tighten rules on transshipping goods through third countries could jeopardize about 70% of China’s exports to the United States, equivalent to more than 2.1% of Chinese gross domestic product. China has increasingly relied on partners such as Mexico, Vietnam and the European Union to assemble or route products bound for the US. The Chinese share of value added in goods ultimately sold in America through these intermediaries rose to 22% last year from 14% in 2017, softening the impact of existing US tariffs. Bloomberg Economics economists Chang Shu, Rana Sajedi and David Qu say stricter enforcement—potentially involving higher duties or new supply-chain disclosure requirements—would amplify the damage from the tariff regime introduced in 2025, erode China’s long-term growth prospects and add deflationary pressure by squeezing exporters’ margins.