A decision by President Trump to close a tariff loophole could change the landscape of online shopping, particularly for the Chinese e-commerce companies behind wildly successful sites, such as Shein and Temu.

Trump revoked a tax loophole that saved companies tens of billions of dollars in fees on imports. Prices on such orders could now go up an average of 30 percent.

President Donald Trump’s sweeping tariff threats have been touch and go. As it stands currently, the 25 percent tax on goods from Mexico and Canada is on ice for a month, but a 10 percent tariff on Chinese goods is set to take effect on Tuesday, via an executive order of questionable legality.