Twitter's new owner and Tesla CEO Elon Musk has sold nearly $4 billion worth of Tesla shares, according to regulatory filings. Musk, who bought Twitter for $44 billion, sold 19.5 million shares of the electric car company from Nov. 4 to Nov. 8, according to Tuesday's filings with the Securities and Exchange Commission. He sold $7 billion of his Tesla stock in August as he worked to finance the Twitter purchase he was trying to get out of at the time.