President Donald Trump has closed a tariff loophole that allowed Chinese e-commerce giants like Shein and Temu to sell low-cost goods in the U.S. without paying duties—a move that is expected to drive up prices for American consumers.

President Trump's campaign to increase tariff rates on imports targets China in particular. In response, China's leaders have levied higher duties on imports of U.S.-sourced products. China has also identified U.