AI server maker Super Micro Computer (SMCI) stock tumbled 15% Thursday after the Wall Street Journal reported that the company is being probed by the US Department of Justice.

The Journal, citing unnamed sources, said the DOJ is investigating the company for potential accounting violations. The issue was first brought to light by the short-selling firm Hindenburg Research in August in a report that accused Super Micro Computer of “glaring accounting red flags," as well as “undisclosed related party transactions" and “sanctions and export control failures.”

Super Micro declined to comment on the matter.

Super Micro makes AI server equipment that uses Nvidia’s GPUs, and Wall Street analysts believe it is a major supplier of hardware to Meta. Its business flourished at the start of 2024 as the tech industry has created a slew of AI software with increasing power demands — and hence, demand for products like Supermicro’s. It’s one of the AI-driven stocks that has surged to record levels, and even with its decline Thursday, shares are still up 57% from last year.

Its gains earned the company a spot in the S&P 500 at the beginning of the year. But the stock has fallen from highs above $1,200 in mid-March before joining the index. Shares dropped in early August when the company missed Wall Street's high expectations in its fiscal fourth quarter earnings report and again later in the month when the company delayed filing its annual 10-K report to the SEC.

In reference to both the scathing Hindenburg report and Super Micro's delayed filing, CEO Charles Liang wrote in a letter to customers on Sept. 3, "Neither of these events affects our products or our ability and capacity to deliver the innovative IT solutions that you rely on every day. Our production capabilities are unaffected and continue operating at pace to meet customer demand."

The company in August reported earnings per share of $6.25 for the fourth quarter, lower than the $8.25 analysts had expected. Its revenue of $5.3 billion came in just below Wall Street's estimate of about $5.32 billion, but more than doubled from the prior year.

Liang said in his letter, "[W]e don’t anticipate any material changes in our fourth quarter or fiscal year 2024 financial results." Still, JPMorgan analyst Samik Chatterjee recently downgraded the stock to Neutral from Overweight, nearly halving his price target from $950 to $500. Shares fell as low as $373 Thursday before recovering in the afternoon to around $400.

Nearly 37% of Wall Street analysts still recommend buying the stock as of Thursday afternoon, according to Bloomberg consensus estimates. Analysts see shares rising to $685 over the next 12 months.