From article introduction

"Over the last decade, a new breed of venture capitalists has emerged: social investors. These so called "impact investors" seek to combine financial returns with social impact by using the tools of venture capital to make principal investments in private, high-growth companies that have the potential to deliver some measurable social or environmental benefit. Building on the success of microfinance in demonstrating the commercial viability of an overlooked asset class, social investors believe that you can achieve a commercial or quasi-commercial return and outsized social impact by betting on innovative entrepreneurs addressing underserved markets. For the social investor, the hockey stick is not a company's valuation, but the liters of clean water delivered, the cases of malaria prevented, the tons of CO2 emissions averted, the lives changed."