Musk became one of Twitter's largest shareholders in April but didn't disclose his stake on time.
The US Securities and Exchange Commission is reportedly investigating Elon Musk for not disclosing his large stake in Twitter on time.
The Wall Street Journal, citing people familiar with the matter, reported that the SEC is looking into his late disclosure. In April, the SEC declined to comment on a potential investigation. The SEC also declined to comment on Wednesday.
Musk acquired a 9.2% stake in Twitter, making him one of the largest shareholders of the social network. He first revealed his stake on April 4, at least 10 days after he was supposed to file a public form to the SEC that investors must submit when they buy more than 5% of a company's shares. The tardy submission allowed him to buy more stock without alerting other shareholders. The filing could have signaled to shareholders that Musk may have been interested in taking control of Twitter.
In late April, Musk struck a deal with Twitter to purchase the company for $44 billion and take it private.
University of Pennsylvania accounting professor Daniel Taylor told The Wall Street Journal that Musk, who also runs Tesla and SpaceX, likely saved $143 million by not reporting his stake earlier.
Musk could not immediately be reached for comment. CNET reached out via Tesla's press email, but the company dissolved its PR department.