Renegotiation and Optimality in Agency Contracts.

The author analyzes renegotiation in a hidden action principal-agent model. Contract renegotiation offers are made by the agent. A refinement is imposed on the principal's beliefs: if precisely one action is optimal with respect to both the principal's and the agent's contracts, the principal believes that the action has been taken. With the refinement imposed, perfect-Bayesian equilibrium allocations are identical to the second best in the classical principal-agent model without renegotiation. When renegotiation is led by the agent and when equilibria satisfy the refinement, equilibrium allocations are ex ante efficient. Copyright 1994 by The Review of Economic Studies Limited.