Aspen Pharmacare's cofounder Gus Attridge of South Africa joins the list with a net worth estimated at $525 million, thanks largely to the company's ballooning stock, which is up 75 percent over the past year. Aspen Pharmacare manufactures drugs in 17 factories including in several African countries, Australia, Mexico, Brazil and Germany. Tanzanian-born Mohammed "Mo" Dewji is one of Africa's most successful young businessmen. He is CEO of METL, a large Tanzanian conglomerate with activities in distribution, textiles, manufacturing, agriculture and real estate. His father, Gulam Dewji, started it as a commodities trading business. After Mo finished studying business at Georgetown University, he returned home and took the reins of the business, transforming it into a manufacturing player. He is also a member of Tanzania's parliament and has a net worth estimated at $500 million.