Consider an agent who can costlessly add mean-preserving noise to his output. To deter such risk-taking, the principal optimally offers a contract that makes the agent's utility concave in output. If the agent is risk-neutral and protected by limited liability, this concavity constraint binds...

Societies provide institutions that are costly to use, but able to enforce long-run relationships. We study the optimal decision problem of using self-governance for risk sharing or governance through enforcement provided by these institutions. Third-party enforcement is modelled as a costly...

"This paper focuses on avoidable moral hazard and offers one explanation for limited insurance markets, for closely held firms, and for seemingly simple as opposed to contingent forms of debt. Agents have random endowments of a consumption good which are such that there are gains to trading...