HONG KONG (Reuters) -Shein confidentially filed papers with Britain’s markets regulator in early June for a potential London listing, two sources said, as the online fast-fashion retailer moves ahead with what could one of the largest IPOs globally this year.

The China-founded company, which was valued at $66 billion in a fundraising round last year, started engaging with its financial and legal advisors to explore a listing on the London Stock Exchange early this year, Reuters reported in May, citing sources.