Shein is reportedly poised to chop its valuation by billions of dollars for its anticipated London listing after President Trump ended a trade loophole that allowed the Chinese fast-fashion firm to offer ultra-low prices.The e-commerce giant is set to cut its valuation to $50 billion – nearly a quarter less than the company’s 2023 fundraising value of $66 billion, three people with knowledge of the matter told Reuters.Shein was reportedly aiming to go public in London in the first half of the year, contingent on regulatory approvals from the UK and China.Shein did not immediately respond to a request for comment.Along with levying a 10% tariff on China, Trump this week ended a longtime trade rule known as the de minimis exemption, which allowed sellers to ship packages worth less than $800 into the US duty-free.Over the past few years, US lawmakers have argued that Shein and Temu have abused the rule.Nearly half of all packages shipped under the exemption come from China, according to a congressional committee report.Exports from Shein and Temu have ramped up in recent years, soaring to $66 billion in 2023 from $5.3 billion in 2018, according to the report.The loophole has allowed the Chinese companies to sell their products at rock-bottom prices – spooking major US companies like Amazon, which last year launched a low-price rival called Haul.The end of the de minimis rule could cause lengthy delays for Shein orders as more of its 1 million daily imports are subjected to customs inspections, experts previously told The Post.US representatives have also claimed the exemption, which helped imports skirt around customs, has allowed Shein and Temu to ship in goods made with forced labor, and products with serious health and safety risks.With Post wires...