Triple Pundit: Impact investing is increasingly expected to close a looming funding gap to achieve the United Nations Sustainable Development Goals (SDGs). According to the U.N., achieving the SDGs by 2030 will require a total annual global spend of $5 trillion to $7 trillion, with an investment gap in developing countries of about $2.5 trillion. But how do the investors who are willing to step up to the plate know that their money is driving real impact?