Jeff Greene is a notable real estate billionaire who made his fortune by buying credit default swaps on subprime mortgage-backed bonds during the housing bubble. These investments resulted in him making over $800 million. Greene began building his real estate empire when he bought his home while earning his MBA at Harvard. By the time he graduated, he owned 18 properties. Presently a resident of Florida, Greene owns over 30 properties in the state. In addition, he owns 3,500 apartments in Los Angeles, three buildings in downtown Manhattan, and estates in the Hamptons and Malibu.