sylvia hall looks at how s.r.i. works and who is doing it. >> reporter: in the world of investing, everything has to add up. but a growing number of investors are calculating a new bottom line into their decision- making. >> the core principles are you need to evaluate non financial factors. investing can't just be about what's your return, and it can't just be about what's your return in the short-term. >> reporter: what started as a movement to protest human rights violations in south africa in the 1980s has grown into a $3 trillion world of pensions, mutual funds and other investments. in s.r.i., investors pick companies that uphold their values. it's a broad field, one investor could avoid companies with grimey environmental records, while another favors companies with transparent corporate governance. >> today, you've got firms like blackrock, deutsche bank, goldman sachs, t.i.a.a. cref, big what i call big institutional actors who have a piece of this going on, who are trying to integrate environmental, social