A Theory of Socially Responsible Investment

Publication Date
Financial Markets Group Discussion Papers DP 845
Publication Date
Paul Woolley Centre Discussion Papers No 84
Publication Authors

We characterize necessary conditions for socially responsible investors to impact firm behavior in a setting in which firm production generates social costs and is subject to financing constraints. Impact requires a broad mandate, in that socially responsible investors need to internalize social costs irrespective of whether they are investors in a given firm. Impact is optimally achieved by enabling a scale increase for clean production. Socially responsible and financial investors are complementary: jointly they can achieve higher surplus than either investor type alone. When socially responsible capital is scarce, it should be allocated based on a social profitability index (SPI). This micro-founded ESG metric captures not only a firm's social status quo but also the counterfactual social costs produced in the absence of socially responsible investors.