It's not Bill Gates, founder of Microsoft (MSFT). It's not Warren Buffett, founder of Berkshire Hathaway (BRK-A) (BRK-B). It is Carlos Slim Helu, with a net worth of $53.5 billion according to Forbes. Slim has major holdings in various telecom companies, including America Movil (AMX), of which he owns a $23 billion interest.
Slim's net worth spiked by $18.5 billion, putting Gates in second place and Buffett in third place.