Shein says it swung to a quarterly loss as its sales slowed after US President Donald Trump removed an import duty exemption on small packages.
It also comes as uncertainty remains over the tit-for-tat US-China tariffs wars, which is currently paused.
The fast-fashion giant, which has its headquarters in Singapore but was founded in China, said it lost $99m (£74.1m) in the first three months of the year, compared with a net income of $395m a year earlier.
The announcement is part of the firm's preparations ahead of its stock market debut in Hong Kong, although the filing did not give any details on the size, timetable or pricing of the planned initial public offering (IPO).
"In response to the increased duties and taxes, we are pursuing a wide range of options, including increasing our prices in the US market to offset a portion of the increased costs," Shein said in the filing.
The company also said the Iran war had hit demand, increased costs and caused delays of deliveries in some markets.
The first-quarter figures also partly reflected a paper loss of $328m due to an accounting change for special investor shares. The shares can be turned into ordinary stock later, and their value can change before a listing.
The filing showed that in the year to the end of March 2026 Shein had 281 million active customers - a rise of more than 16% on a year earlier - who placed a total of more than one billion orders.
On 10 July, the China Securities Regulatory Commission (CSRC) gave Shein approval for a Hong Kong share sale after failed attempts to list in New York and London.
The Hong Kong share listing is expected to take place in the coming months.
The figures show the impact of a Trump-signed executive order to end a global tariff exemption that had been used by US shoppers of low-cost goods.
That order, which came into effect on 29 August 2025, broadened an earlier presidential action which specifically targeted cheap products from China and Hong Kong to cover the rest of the world.
The so-called de minimis exemption had allowed goods valued at $800 or less to enter the US without paying any tariffs. US consumers relied on the exemption to buy cheap goods from online commerce sites like Shein and Temu.
The White House said the global exemption was being used to "evade tariffs and funnel deadly synthetic opioids" to the US.
"The removal of the US de minimis exemption has had an adverse impact on our sales in the US and the overall growth of our net revenues," Shein said in the filing.
Earlier in July, the European Union imposed a €3 (£2.56; $3.42) levy on low-value e-commerce imports.
The measure is aimed to curb what the trading bloc has said is unfair competition from China.
Source: BBC
--Agencies
