Information is power, and this self-made billionaire controls some key taps through which it flows. Not content to have created the most trusted source around for mutual fund research and related data, Mansueto has built Morningstar into a one-stop shop to help Americans master investing. "The notion that data and information can be empowering is something that drives Joe," says Don Phillips, a longtime Morningstar executive. He has reinvested in the city via philanthropy (U. of C.'s library) and media (he's a majority owner of Time Out Chicago and part of the consortium that owns the Sun-Times and Reader). So far, he's the only Chicagoan (with his wife, Rika) to join Warren Buffett in signing the Giving Pledge, promising to donate at least half his wealth to charity.

Photograph: CHRIS STRONG