Number 3: Warren Buffett

Warren Buffett (USA) - $50 billion, Berkshire Hathaway

Buffett, 80, has run his Omaha, Nebraska-based conglomerate since 1965. Its interests run from railroads to ice cream.At only six years of age Warren purchased 6packs of Coca-Cola from his grandfather's grocery store
for 25cents and sold them for a nickel, pocketing a five cents profit.While other children of his age were playing hopscotch and jacks, Warren was up making money. Five years later Warren took his steps in the high world finance. At 11years of age he purchased three shares of Cities Services Preferred for $38 per share both for himself and his elder sister, Doris. Shortly after buying stock they fell $27 each share. A frightened but resilient Warren stood to his shares until they rose up to $40. Warren promptly sold his shares but unfortunately they again rose up to $200. This was a lesson for Warren that helped him in later years.       
In 2006 he pledged to give away 99 percent of his wealth to the Bill and Melinda Gates Foundation and family charities. So far he has given $8 billion to the Gates Foundation.