HONG KONG/LONDON (Reuters) - Fast fashion retailer Shein is considering asking UK regulators to waive listing rules that require at least 10% of its shares to be sold to the public in its planned London flotation, two people with knowledge of the matter said.

The company is exploring this option to facilitate its IPO, one of the people said.

If granted, it would likely be the first time that a company in London has been allowed to list below the recent 10% rule.

Singapore-headquartered Shein, which sells $5 tops and $10 dresses mostly made in China, in June filed confidentially with the Financial Conduct Authority (FCA) for a London listing.

However, Britain's financial regulator is taking longer than usual to approve its application, Reuters reported last week.

The people declined to be identified as they were not authorised to speak to the media.

Shein had no immediate comment.

Shein was valued at $66 billion in a fundraising round last year. A 10% flotation at that valuation would make the IPO worth $6.6 billion. The biggest European IPO this year was perfume and fashion company Puig's $2.9 billion deal, according to Dealogic.

The current valuation of Shein and how much it is looking to raise via the London listing was not immediately known.

London changed its listing rules in 2021 to boost the attractiveness of the venue for companies. It cut the proportion of shares an issuer is required to float to 10% from 25%, reducing potential barriers for large IPOs, the FCA said at the time.

In July, Britain ushered in the biggest reform of company listing rules in more than three decades to help it compete more effectively with New York and the European Union for new issuers.

Shein began to explore a listing on the London Stock Exchange early this year, Reuters reported in May, citing sources. The China-founded company's original plan to list in New York was derailed after opposition from U.S. lawmakers.

Shein is also waiting for China's securities regulator to approve its plans for a London IPO, Reuters previously reported. Its revenues are expected to hit $50 billion this year, up 55% from 2023, according to Coresight Research.