Fast-fashion retailer Shein is being sued by rival Hennes & Mauritz AB for copyright infringement in Hong Kong, where the litigation aimed at mitigating the threat posed by its Chinese rival has been underway since 2021.

Zoetop Business Co., the Hong Kong-based entity that previously owned Shein, is among the defendants, as is Shein Group Ltd., according to a writ of summons issued in July 2021 and recently obtained by Bloomberg News. Stockholm-based H&M asked for unspecified damages and an injunction to stop Shein from infringing on its copyright and trademarks.

Details of the filing, including photos of dozens of items from swimwear to sweaters that H&M said was evidence that Shein stole its designs, were released to the public after a hearing at the Hong Kong High Court on June 21. The next hearing is slated to take place on July 31.

H&M confirmed having filed lawsuit against Shein in Hong Kong, claiming the latter “in multiple cases has infringed on our designs”, according to a spokesperson of the Swedish fashion retailer. Shein didn’t respond to Bloomberg request for comment.

While there have been many allegations of intellectual property infringement leveled against the online retailer in the past 3 years, H&M’s action is a rare case of an established fast-fashion rival filing suit. Shein’s sales in 2021 were far less than those of H&M, but its skyrocketing sales growth, fueled by the rapid launch of new products and strong digital marketing strategies on social media, drew the attention of companies and designers in western markets including the US and Europe.

Shein sued Chinese-owned online retailer Temu last year in the US, alleging trademark and copyright infringement as well as “false and deceptive business practices.” Temu countersued, alleging the company violated antitrust laws by using threats and intimidation to stop clothing manufacturers from working with it.

There have been more than a dozen lawsuits against Shein this year alone in the US brought by plaintiffs alleging intellectual property violations. And some American lawyers have accused the company of a pattern of racketeering activity, an approach commonly used to target organized crime. They say Shein’s intellectual property theft is an integral part of its business model, and the company typically offers a small cash settlement to those designers.

--With assistance from Bruce Einhorn.