Tennis legend Roger Federer has joined the rank of global billionaires with a net worth of US$1.3 billion, mostly stemmed from the long-term sponsorship deals signed during his 24-year career.Tennis legend Roger Federer has joined the rank of global billionaires with a net worth of US$1.3 billion, mostly stemmed from the long-term sponsorship deals signed during his 24-year career. VnExpress English