He made his fortune selling financial-information terminals to Wall Street firms. Bloomberg L.P also began a radio network (the flagship station is 1130 WBBR-AM in New York City).
In 2001 he spent about $69 million, or $92 a vote, to defeat Mark Green in the mayoral election to replace Rudy Giuliani, who was required to leave office by term limits. A lifelong Democrat, Bloomberg ran on the Republican ticket to avoid the Democratic primaries.
Michael Bloomberg is a member of the Phi Kappa Psi fraternal organization. He graduated from Johns Hopkins University in 1964 with a BS in electrical engineering and Harvard University with a Master of Business Administration degree. Bloomberg has donated $100 million to Johns Hopkins.
Bloomberg was born and raised in Medford, Massachusetts, a suburb of Boston.