Berkshire Hathaway CEO Warren Buffett's net worth has grown by over 7% this year to around $117 billion as his company's shares rallied, Bloomberg reported. The 91-year-old is now back among the world's five richest people, after falling to as low as world's 11th richest person in October. World's richest person Elon Musk's wealth has dropped by 15% this year.