According to an Apple filing with the U.S. Securities and Exchange Commission today, Tim Cook sold 20,178 shares of his company’s stock in a series of transactions over the past two business days. The sales started at $547 per share and climbed to $551 before the last transaction, which left Apple’s Chief Executive Officer with $11.1 million.

Cook, who earns a bit more than $1 a year in Apple salary, was awarded 1 million shares of Apple last year, which vest in 2016 and 2021. Those shares are now worth over half a billion dollars.

Apple is the world’s most valuable company with stock valued at $552 upon today’s closing bell and continued to climb in after-hours trading.