An offshoot of hacking collective Anonymous says one of China's largest chemical companies is a fraud.
Anonymous Analytics published a 67-page report targeting Tianhe Chemicals, a firm that listed in Hong Kong just three months ago and is valued at $7.6 billion.
The report claims the company vastly overstated its revenue and profits, produced contradictory tax data and kept two sets of books.
Tianhe denied the allegations. Its shares were suspended after falling 5% on Tuesday.
"The report contains errors of fact, misleading statements and malicious accusations against the company and its directors," it said in a regulatory filing.
Tianhe said short sellers had targeted the company, adding it was working on a longer statement to refute the allegations "as soon as practicable."
Short sellers profit by betting a company's shares will fall, often releasing damaging information about the firm.
They've gone after other Chinese publicly-traded companies before, making similar claims of fraud and accounting regularities.
One of the most notable examples was a takedown of Sino-Forest by Carson Block of Muddy Waters Research. The Toronto-listed Chinese firm eventually filed for bankruptcy after Block accused the company of fraud.
The Anonymous Analytics authors -- who remain anonymous -- have already targeted Qihoo 360, another mainland Chinese firm. Investors shrugged off those allegations, and the company's shares are up 10% this year.
Beijing has complained that short sellers have unfairly focused their efforts on Chinese companies.
While the accusations against Tianhe could not be corroborated, they are serious in nature and could lead to criminal prosecutions if proven.
Anonymous Analytics claims that Tianhe told investors revenue was growing by more than 20% a year, while filing documents to Chinese regulators that showed significantly lower revenue and income.
"We have conducted months of due diligence, field research and analysis which show that Tianhe is a massive fraud and one of the largest stock market scams ever conceived,' the report says.
Tianhe made headlines earlier this year after questions were raised over connections between Joyce Wei, the daughter of the company's chairman, and banks that worked on the company's initial public offering.