Goods from mainland China and Hong Kong valued under US$800 (HK$6,240) are no longer exempt from import tariffs imposed by the United States, adding to the challenges faced by Chinese cross-border e-commerce giants.

The US administration's removal of the exemption means the covered shipments will be subject to regular import tariffs as well as the new additional 10 percent duty which came into effect at 12.01am Eastern Standard Time – 1.01pm in Hong Kong – on February 4, according to the Hong Kong Trade Development Council’s research arm.

Temu, the overseas e-commerce platform owned by Pinduoduo, and Singapore-headquartered rival Shein have been expanding their market shares in the US with low-priced products as cheap as US$2.

Temu and Shein are expected to record a sales volume of about US$100 billion in 2024, according to Coresight.