Chinese e-commerce giant Alibaba Group is back on the US government's annual list of "notorious markets" that sell pirated goods.
The Office of the US Trade Representative said on Wednesday that Alibaba's online marketplace Taobao sells "high levels" of counterfeit goods and is slow to respond when companies complain about the knock-offs.
USTR took Alibaba off the blacklist in 2012, but several US trade groups successfully sought to get it reinstated.
"There are a lot of victims here," including US companies that lose sales to fakes and consumers who wind up with shoddy goods, said Stephen Lamar, executive vice president at the American Apparel & Footwear Association, which wanted Alibaba back on the list.
Alibaba Group President Michael Evans said the company is "disappointed."
Alibaba polices the market more effectively than it did four years ago, he said.
Evans questioned whether the USTR decision was "based on actual facts or was influenced by the current political climate." During the presidential campaign, Donald Trump blasted China for stealing intellectual property.
In 2014, Alibaba sold $US25 billion ($A34 billion) worth of stock on the New York Stock Exchange in the biggest initial public offering on record. Winding up on the notorious markets listing again is another blow to its reputation.
In 2015, Chinese regulators issued an unusual, scathing report that accused Alibaba of failing to do enough to prevent the sale of fakes on its websites.
