4. The Koch Family

Back in 1940, Fred C. Koch launched Koch Industries as an oil refinery and it is now the second-largest private company in the world. The conglomerate still has stakes in oil, but has expanded to real estate, ranching, commodity trading, chemicals, finance, and even household items. We imagine the key is to diversify their $89 billion portfolio. Those on the social scene probably recognize David Koch, the company's VP, who has been a trustee of the American Ballet Theatre for 25 years.


7 of 10