The global financial crisis and the accounting scandals of large companies have stimulated a new assessment of the contribution of enterprises and financial institutions to economic prosperity and the greater public good. This assessment has led to a re-evaluation of the relationship of businesses to their stakeholders and to underlying economic structures. It has also drawn attention to the ideas of social entrepreneurship and impact investing. In this chapter we explore these ideas by considering their philosophical basis in light of corporate social responsibility. We present six case studies: Grameen Bank, Tendris, two initiatives by the Noaber Foundation and two by DOB Equity for Africa. These social entrepreneurs and impact investors are distinguished by their social objectives, values and worldview, with a focus on the justified interests of all stakeholders. In the next decade, social entrepreneurs and impact investors will become a growing new investment sector and play an increasing role in global development.