A model of corporate governance must explain (i) why governance matters; (ii) variation in governance across firms (i.e., be responsive to the Demsetz and Lehn, 1985, critique); and (iii) the positive correlations found empirically between quality of corporate governance and corporate performance. The model presented here satisfies these three criteria. Moreover, the model explains the correlation between firm size and executive compensation and why empirical estimates of managerial incentives seem too low, among other phenomena.

Firms undertake a variety of actions to reduce risk through diversification, including entering diverse lines of business, taking on project partners, and maintaining portfolios of risky projects such as R&D or natural resource exploration. By a well-known argument, securities holders do not directly benefit from risk-reducing corporate diversification when they can replicate this diversification on their own. Moreover, shareholders should be risk neutral with respect to the unsystematic risk that is associated with many research projects. Some have argued that corporate risk reduction may be of value, or can otherwise be explained by, the agency relationship between securities holders and managers. We argue that the value of diversification strategies in an agency relationship derives not from its effects on risk, but rather from its effects on the principal's information about the agent's actions. We demonstrate by example that diversification activities may increase or decrease the principal's information, depending on the particular structure of the activity