Incomplete Contracts, Specific Investments, and Risk Sharing

An optimal contract design problem is considered. Contracts which are incomplete and simple are used to investigate the extent to which constrained revisions can mitigate inefficiencies resulting from contractual incompleteness. An optimal contract is characterized in two cases. First, when a contract is being used to facilitate trade between two risk-neutral parties who must make relationship-specific investments, it is possible to implement the first-best by a simple contract. Second, when a contract is being used to share risk, it is generally not possible to implement the first-best.