The Securities and Exchange Commission (SEC) is investigating Elon Musk and his brother, Kimbal, on recent stock sales by Tesla Inc (NASDAQ:TSLA), the Wall Street Journal reported.
Citing people familiar with the matter, the WSJ said Musk and his brother are being investigated for violating insider-trading rules.
The SEC’s investigation reportedly began last year after Kimbal Musk sold US$108mln worth of Tesla shares a day before Musk polled Twitter users asking whether he should offload 10% of his stake in Tesla, on 7 November.
Elon Musk told the Financial Times in an email, Kimbal Musk did not know about the Twitter poll ahead of his sale, adding that his lawyers were "aware" of the poll.
The poll caused Tesla’s shares to drop more than 16% over the period between 5 November and 9 November, and are currently down 33% since the announcement at US $800.77.
Musk continues to court controversy from regulators, financial and automotive.
Last week, he accused the SEC of trying to “chill” free speech for reprimanding him over tweets about Tesla stock.
He also called US automotive regulators “fun police” after they forced the recall of more than 800,000 Tesla vehicles citing safety concerns over an external speaker that made, among other sounds, fart noises.