I analyze corporate social responsibility (CSR) from economic and financial perspectives, and suggest how it is reflected in financial markets. CSR is defined as a programme of actions to reduce externalized costs or to avoid distributional conflicts. It has evolved in response to market failures, a Coasian solution to problems associated with social costs. The analysis suggests that there is a resource-allocation role for CSR programmes in cases of market failure through private-social cost differentials, and also where distributional disagreements are strong. In some sectors of the economy private and social costs are roughly in line and distributional debates are unusual: here CSR has little role to play. Such sectors are outnumbered by those where CSR can play a valuable role in ensuring that the invisible hand acts, as intended, to produce the social good. It can also act to improve corporate profits and guard against reputational risks.