This paper surveys the theoretical literature on corporate social responsibility (CSR) through two recurrent lenses: externalities and asymmetric information. It reviews how CSR-type objectives interact with pollution regulation, market structure, and demand-side externalities, yielding welfare gains but potentially ambiguous effects on output and emissions. It then analyzes CSR as a credence attribute under hidden actions and hidden types, highlighting market unraveling, greenwashing incentives, and the role of disclosure, certification, and voluntary standards. Overall, CSR emerges as an equilibrium response shaped by industrial organization, policy design, and information institutions rather than as a purely altruistic deviation from profit maximization.
