Elon Musk increased his stake in SpaceX last year by purchasing $1.4 billion of stock from current and former employees, part of a series of moves leading up to the company’s initial public offering that increased his sway over the company.

The large secondary stock purchase was made through the mega-billonaire’s trust. It was disclosed in a draft of SpaceX’s confidential IPO prospectus reviewed by The Information. The document also revealed a new plan to award Musk with tens of millions of shares if SpaceX’s market cap increases to as high as $6.6 trillion.