"Last week, short-sellers betting against Tesla lost big after the CEO tweeted about taking the company private. Tesla shares rose 11 percent following Musk's tweet Tuesday, meaning short sellers lost about $1.3 billion in mark-to-market losses, according to estimates from financial technology and analytics firm S3 Partners," CNBC reports. On Friday, Kalman Isaacs and William Chamberlain filed complaints against Tesla in a federal court in San Francisco, accusing its founder and CEO of artificially boosting his company's stock price in an attempt to hurt short sellers.