Alibaba's ecosystem comprises China's biggest Internet marketplace, and it's again in the crosshairs of United States Trade Representative Michael Froman.

The USTR's annual report this year says that Alibaba's Taobao.com e-commerce platform is an important concern due to the large volume of allegedly counterfeit and pirated goods available and the challenges right holders experience in removing and preventing illicit sales and offers of such goods.

The USTR says Alibaba is making headway in eliminating counterfeits from its platform, but that current levels of reported counterfeiting and piracy are still unacceptably high.

"This Notorious Markets List illustrates the seriousness of copyright piracy and trademark counterfeiting in online marketplaces," said Froman. "The 2016 List underscores the need for accountable governments everywhere to take on these forms of piracy and counterfeiting at every stage of the global supply chain to prevent final products that put health and safety of end-consumers at risk."

Alibaba was also on the list in 2011, and the Notorious List this year counts more than 20 online and offline marketplaces around the world that assist counterfeiters to sell their wares.

The USTR says it will closely monitor the implementation and effectiveness of the set of prospective actions described in Alibaba’s Notorious Markets List submission throughout 2017.