Carlos Slim, the Mexican billionaire, derived his wealth primarily from telecommunications companies Telmex, Telcel, and America Movil. He was the world's richest person for several years (2010-2013) due to his near-monopoly in Mexican telecom markets. While options like Microsoft (Bill Gates) and Berkshire Hathaway (Warren Buffett) have produced billionaires, Slim's fortune specifically came from these Latin American telecom giants.