Senator Elizabeth Warren, a longtime critic of Tesla Inc (TSLA.O) boss Elon Musk, on Monday raised concerns that the automaker's board had failed to address the risks posed by his role as CEO of Twitter.
Musk's $44 billion takeover of the social media platform in October has been marked by chaos and controversy, with even Tesla bulls questioning if he is too distracted to properly run the EV maker, where he is personally involved in production and engineering.
Investors have urged Musk to step down as Twitter CEO and punished Tesla stock, which is down nearly 60% this year and hit a fresh two-year low on Monday.
Warren, a progressive Democrat who has previously clashed with Musk over her calls for billionaires to pay more taxes, said that a company's board was responsible for ensuring that its controlling shareholder did not treat it "as a private plaything."
"The first weeks of Mr. Musk's Twitter ownership have raised questions about possible violations of securities or other laws, including whether Mr. Musk is funneling Tesla resources into Twitter," she said in a letter to Tesla's board chair, Robyn Denholm.
James Murdoch, a Tesla director, testified in court last month that the company's audit committee discussed Musk's deployment of Tesla engineers at Twitter, saying this should not take away from their work at the car maker.
Denholm could not immediately be reached and Tesla did not respond to a request for comment. Musk did not immediately respond to Reuters' request for comment.
Musk himself has sold $40 billion in Tesla stock this year, further frustrating investors.