(CNN) Tesla CEO Elon Musk just zoomed past Warren Buffett on the Bloomberg Billionaires Index to become the world's seventh wealthiest person. Musk's fortune rose more than $6 billion Friday after Tesla's stock surged 11% to a record $1,544 per share, according to Bloomberg. At the same time, Buffett's fortune fell this week after he donated nearly $3 billion worth of Berkshire Hathaway stock to charity — part of his plan to give away most of his wealth to philanthropic ventures.