Online retailers Shein and Temu have warned their American customers about "price adjustments" due to the evolving trading landscape.In nearly identical announcements last week, the e-commerce companies said operating expenses had risen due to "recent changes in global trade rules and tariffs," and that they would be raising prices from Thursday onward as a result.Newsweek reached out to Temu and Shein via email and online contact form, respectively, for comment.Why It MattersShein and Temu, both owned by Chinese parent companies, have grown into two of the world's most popular and widely used online marketplaces for affordable clothing and goods. The two have attracted tens of millions of customers in the United States, who will be directly affected by the upcoming "price adjustments."What To KnowNeither company disclosed the extent and duration of the price increases. Both Shein and Temu typically ship from China, a key target of the Trump administration's tariffs, as well as regional distribution centers across the globe.Reciprocal tariffs, announced by President Donald Trump on April 2, have been put on a 90-day hold for all countries except China, whose imports are now subject to a 145 percent tax when entering the U.S. The administration has said that these new duties could be combined with existing tariffs, resulting in some Chinese goods facing a tariff of up to 245 percent.Beijing, in response, has imposed its own 125 percent tariff on American goods entering the country.On April 2, Trump also signed an executive order closing the "de minimis" duty-free exemption for goods valued at under $800. The White House estimates that over four million of these de minimis parcels are processed by U.S. Customs and Border Protection (CBP) every day, and said that the move would target "deceptive shipping practices by Chinese-based shippers, many of whom hide illicit substances, including synthetic opioids, in low-value packages."According to economist Thiemo Fetzer, both Shein and Temu "built their entire business model" around exploiting this customs loophole. Rather than shipping orders in bulk, which would push them over the $800-dollar threshold, he said both operate by shipping "millions of individual small parcels directly to consumers, bypassing the tariff system entirely.""The de minimis exemption was designed for a pre-digital era, allowing small value parcels...to enter without customs duties or formal entry requirements," Fetzer told Newsweek. "This made sense when international shipping of small parcels was rare, but these Chinese platforms essentially industrialized this exception."Fetzer said that the end of de minimis would result in price increases for customers and difficulties for those who have built smaller businesses around "drop-shipping" from these platforms. However, he said that this could potentially level the "uneven playing field" in which Chinese exporters such as Temu and Shein had so far enjoyed a "structural advantage" over domestic retailers "who had to incorporate duties into their cost structures.""[De minimis] also meant lost tax revenue and potentially circumvented product safety standards," he said. "The business model was essentially arbitraging regulatory differences rather than creating genuine economic value."Nicholas Lardy, an expert in Chinese trade policy, previously told Newsweek that closing the de minimis loophole and subjecting every small shipment to tariffs could prove extremely difficult to customs authorities."There are millions of these packages coming in every day," he said. "And the customs services doesn't have the manpower to assess them and charge a tariff. So, you know, after two days, they have to give it up."What People Are SayingShein and Temu, in customer notices issued last week: "Due to recent changes in global trade rules and tariffs, our operating expenses have gone up. To keep offering the products you love without compromising on quality, we will be making price adjustments starting April 25, 2025.""We're doing everything we can to keep prices low and minimize the impact on you," both notices said.Thiemo Fetzer, professor of economics at the University of Warwick, told Newsweek that Temu and Shein have "essentially built a parallel import system that circumvents the traditional customs infrastructure... With the end of de minimis shipping, each of these small parcels now requires formal customs processing and duties. The administrative burden alone makes the model less economical, not to mention the actual tariffs now due. This naturally leads to price increases as we're seeing.""The adjustment might be painful in the short term," he added, "but it could lead to more sustainable and balanced trade relationships where competition happens on product quality and genuine efficiency rather than regulatory arbitrage."One Reddit user on the temu-focused community r/TemuThings wrote: "It's game over for cheap prices. Temu is going to start paying 145% tariffs on shipments starting 4/25, assuming it will take a week to reach Customs. They will pass that on to you by raising prices substantially to make up the cost."What Happens NextU.S. Treasury Secretary Scott Bessent has reportedly called the back-and-forth tariff war with China "unsustainable," and the president has similarly indicated that the administration may soon soften its approach to the country.On Tuesday, Trump said that the "very high" tariffs on Chinese goods will "come down substantially, but it won't be zero."