9) (Edward) Johnson family (Net worth: $26 billion)

The Johnson family members own around 49 percent of Fidelity, the second largest mutual fund company in the US. It manages assets worth around $1.8 trillion. The Boston-based behemoth was founded by Edward C. Johnson II in 1946. His son Edward “Ned” Johnson III ran the company from 1977 to 2014, when he stepped down as CEO. Currently he is the chairman and his daughter Abigail is the CEO.