Shein, the prominent fast fashion retailer associated with China, has confidentially filed for a public listing in London amidst mounting scrutiny in the U.S., according to a source familiar with the matter speaking to CNBC on condition of anonymity.

Originally, Shein had filed confidentially for an initial public offering (IPO) in the U.S. in November but turned to London after facing opposition from American lawmakers.

Concerns have been raised in the U.S. regarding Shein’s supply chain practices, including allegations of forced labor, as well as its use of a U.S. tax exemption for low-value imports known as de minimis.

While Shein still prefers a U.S. IPO, sources indicated that the move to file in London does not guarantee the IPO will proceed there, CNBC has reported.

Previously, Shein had sought approval from Chinese authorities to go public in the U.S., and it remains uncertain if Beijing has sanctioned the London listing.

Written by B.C. Begley