Cynthia Ringo and Nancy Pfund are succeeding in a testosterone-filled world by committing to do more than just make money for their investments. Out of 462 venture capital firms in the US, only their company -- San Francisco-based DBL Investors -- is run just by women.

Ringo is a former managing director at Vantage Point Venture Capital and Pfund was previously an investment managing director at Hambrecht & Quist, a boutique acquired by JP Morgan.