Michael Bloomberg

Michael Loccisano/Getty Images

Michael Bloomberg

Age: 67
Residence: New York
What keeps him busy: Mayor of New York, Founder of Bloomberg

After being fired from investment bank Salomon Brothers in 1981, Bloomberg used his $10 million severance package to set up his own financial software services company, eventually making him the richest man in New York—as well as one of the richest men in the world. Today closely held Bloomberg has more than 150,000 global subscribers for its eponymous terminals, which rent for $1,500 a month and up. The company also includes a cable network, a radio station, a Web site, and a magazine. Bloomberg stepped down as CEO of his company when he was elected mayor of New York in 2001, and he is now making a bid for a third four-year term in office. In addition to his mayoral duties, Bloomberg, often cited as a potential Presidential candidate, is an active though frequently anonymous philanthropist who has given away hundreds of millions of dollars.