Egypt has the largest number of billionaires in Africa, according to a new wealth report by Forbes magazine, with the majority belonging to just two families. The list of Africa\'s 40 richest people published by Forbes shows seven billionaires have Egyptian citizenship -- the most of any single country on the continent. Most are members of either the Sawiris or Mansour dynasties. The 40 wealthy figures on the list have a combined net-worth of US$649 billion. Richest man in Africa is Aliko Dangote, Nigerian owner of the Dangote Group, with an estimated fortune of $10.1 billion. In third place is Nassef Sawiris, head of Orascom Construction Industries, Egypt\'s largest-listed company, with a net-worth of $4.75 billion. At number seven is his brother Naguib Sawiris, the founder of Orascom Telecom and perhaps the best-known businessman in Egypt, with a fortune of $2.9 billion. Onsi Sawiris, father of Naguib and Nassef, and founder of the Orascom conglomerate, is ranked ninth thanks to estimated wealth of $2.6 billion. Named 13th richest is Mohamed Mansour, one of three brothers involved in the Mansour Group whose holdings include General Motors and Caterpillar distribution deals, Egypt\'s largest supermarket chain and real estate developer Palm Hills Developments. His net-worth is placed at $1.7 billion. His brothers Yasseen and Youssef Mansour are in 14th and 15th places, each valued at $1.55 billion. Mohamed Al Fayed, who lives in Britain but does not hold citizenship there, is ranked 16th, with his hotel and retail interests contributing to an estimated fortune of $1.3 billion. In 19th place is Shafik Gabr, managing director of the ARTOC Group, a real estate-engineering-consumer products-media conglomerate, with a net-worth of $730 million. Forbes said the list was calculated by using stock prices and exchange rates as of 2 November 2011.