Socially responsible investing tends to be defined by what it won't do—no funding for defense contractors, say, or companies with child labor. Asad Mahmood, who runs social-investment funds for Deutsche Bank, is trying to go directly to the source, lending to businesses with powerful social impact. So Deutsche's Eye Fund I, with nearly $20 million in capital, is financing eye hospitals—specifically, eye hospitals in developing nations that deliver urgently needed basic care, have good business practices, and serve both patients who cannot pay at all and patients who can. "Our vision is to be the investment bank for social capital," Mahmood says. His next gambit: an investment fund to help create affordable housing in the United States.