It reported the Securities and Exchange Commission is scrutinizing internal communications by company CEO Sam Altman.
It's part of an investigation into whether the company's investors were misled.
Citing sources, the WSJ reported the SEC has sought internal records from current and former officials and directors at the ChatGPT creator.
It is also said to have sent a subpoena to the company in December.
The move followed a decision by OpenAI's board in November to fire Altman as CEO and kick him off the board.
They argued at the time - quote - "he was not consistently candid in his communications with the board."
But Altman dramatically returned as CEO just days later.
Microsoft-backed OpenAI also unveiled a new initial board with former Salesforce co-CEO Bret Taylor as chair.
The Journal said SEC officials in New York have asked that some senior OpenAI executives preserve internal documents while they conduct the investigation.
The probe comes as Altman is reportedly in talks to raise billions of dollars for a chip venture to expand its ability to power AI.
The SEC declined to comment on the possible investigation.
OpenAI and Microsoft did not immediately respond to Reuters' requests for comment.
