Public tech companies as a whole are having a bad week, but entrepreneur Elon Musk is having an especially bad day.
Musk, who first rose to success as a co-founder of PayPal (pypl), is currently the largest shareholder in electric carmaker Tesla (tsla), as well as solar panel company SolarCity (scty). Thanks to significant stock price drops for both companies today, Musk lost a total of $296.6 million, on paper, by the close of the market on Wednesday.
Tesla, which Musk co-founded and currently leads as the company's CEO and chairman, saw its price drop by 3.1%, from $150.50 per share to $143.67. According to a company filing to the SEC from January 27, Musk owns 28.9 million shares, or a 22% stake.
As for SolarCity, co-founded by Musk's cousins Peter and Lyndon Rive and of which he's the chairman, it saw its price drop by 29.3% by the end of Wednesday. It opened at $19.42 and closed at $18.63. Musk owns a 22% stake in the solar panel company, or 21.275 million shares, according to an SEC filing from January 4.
Musk's day got better after the close; Tesla shares were up 11% in after-hours trading despite results that missed expectations.
With that said, Musk's net worth is estimated to be around $10.5 billion, according to Forbes's most recent math. He also has SpaceX, his private space exploration company, which recently successfully landed a reusable rocket after several failed attempts.