(Reuters) -The U.S. Department of Justice is investigating Super Micro Computer, the Wall Street Journal reported on Thursday, nearly a month after short-seller Hindenburg Research alleged “accounting manipulation” at the AI server maker.

Super Micro’s shares fell about 12% following the report.

The WSJ report, which cited people familiar with the matter, said the probe was at an early stage and that a prosecutor at a U.S. attorney’s office recently contacted people who may be holding relevant information.

The prosecutor has asked for information that appeared to be connected to a former employee who accused the company of accounting violations, the report added.

Super Micro had late last month delayed filing its annual report, citing a need to assess “its internal controls over financial reporting,” a day after Hindenburg disclosed a short position and made claims of “accounting manipulation”.

The short-seller had cited a three-month investigation that included interviews with former senior employees of Super Micro and litigation records.

Hindenburg’s allegations included evidence of undisclosed related-party transactions, failure to abide by export controls, among other issues.

The company had denied Hindenburg’s claims.

Super Micro on Thursday declined to comment on the report, while the DOJ said it cannot confirm or deny the existence of such a probe.

A Reuters review of tender documents earlier this year showed Chinese entities acquired high-end Nvidia chips embedded in server products made by several companies, including Super Micro, through resellers.

The U.S. government has been cracking down on the sale of such technology to China.

Super Micro has been a big winner in the generative AI boom, as businesses bet on the technology needed to power applications such as ChatGPT, sending its market value to $67 billion in March from roughly $4.4 billion.

The rally in AI stocks has since cooled, as investors realized the payoff on companies’ heavy investments would be slower than expected.

(Reporting by Akash Sriram and Aditya Soni in Bengaluru; Editing by Shreya Biswas)