Investing is anything but a game for "Super Mario" Gabelli, the self-made billionaire investor and founder and CEO of GAMCO Investors. The firm oversees the mutual fund- and securities-related portion of Gabelli's financial empire. It provides advisory services to some 20 mutual funds and 10 closed-end funds under the Gabelli, GAMCO, and Comstock brands. Most of the company's approximately $34 billion in assets under management are invested in stocks, though company also has a well-performing money-market fund. GAMCO also offers wealth management services for private clients and institutional investors such as pension plans, endowments, and municipalities. Gabelli controls the firm.