We present a Theory of Contracts under costly enforcement in the context of a dynamic relationship between an uninformed buyer and a seller who is privately informed on his persistent cost at the outset. Public enforcement relies on remedies for breach. Private enforcement comes from severing relationships. We first characterize aggregate enforcement constraints ensuring that trading partners do not breach contracts unduly. Whether a long-term contract is enforceable does not depend on the distribution of penalties for breach between the buyer and the seller. While under complete information, the optimal contract would remain stationary, non-stationarity might arise under asymmetric information. Enforcement constraints are time-dependent and easier to satisfy as time passes. Indeed, a high-cost seller may be tempted to trade high volumes at high prices at the beginning of the relationship before breaching the contract later on. Yet, such take-the-money-and-run strategy becomes less attractive as time passes and can be prevented with back loaded payments. The optimal contract thus goes through two different phases. First, quantities and prices increase at the inception of the relationship. Later on, the contract looks more stationary. Long-run screening distortions encapsulate the quality of enforcement, offering de facto a link between the quality of the legal system and contractual performances. / Nous présentons une théorie des contrats avec exécution coûteuse dans le contexte d'une relation dynamique entre un acheteur non informé et un vendeur avec information privée quant à son coût persistant au départ. L’exécution publique des contrats s'appuie sur les recours pour violation. L’exécution privée consiste à de rompre les relations. En premier lieu, nous caractérisons les contraintes d'exécution globale. La possible exécution d’un contrat à long terme ne dépend pas de la distribution des pénalités pour rupture entre l'acheteur et le vendeur. Sous information complète, le contrat optimal resterait stationnaire, alors qu’il pourrait être non stationnaire lorsque l'information est asymétrique. Les contraintes de l'application dépendent du temps et sont plus faciles à satisfaire à mesure que le temps passe. En effet, un vendeur avec des coûts élevés peut être tenté d'échanger de grandes quantités à des prix élevés au début de la relation avant de rompre le contrat par la suite. Pourtant, telle stratégie, prendre l’argent et courir, devient moins attrayante à mesure que le temps passe et peut être évitée. Le contrat optimal passe donc par deux phases différentes. Tout d'abord, les quantités et les prix augmentent lors de la création de la relation. Plus tard, on le contrat semble plus stable. Les distorsions dues au dépistage de long terme signalent, ce qui suggère de facto un lien entre la qualité du système légal et les performances contractuelles.

This paper shows that supervision with soft information is valuable whenever supervisors and supervisees collude under asymmetric information and proceeds then to derive an Equivalence Principle between organizational forms of supervisory and productive activities. We consider an organization with an agent privately informed on his productivity and a risk averse supervisor getting signals on the agent's type. In a centralized organization, the principal can communicate and contract with both the supervisor and the agent. However, these two agents can collude against the principal. In a decentralized organization, the principal only communicates and contracts with the supervisor who in turn sub-contracts with the agent. We show that the two organizations achieve the same outcome. We discuss this equivalence and provide various comparative statics results to assess the efficiency of supervisory structures.

What is the most efficient way of designing incentives in an organization? Over the past five decades, agency theory has provided various answers to this crucial question. This line of research suggests that, depending on the organizational context, the optimal approach to providing incentives may involve either relying on collective compensations or, conversely, employing relative performance evaluations. In the first scenario, cooperation among agents is the key aspect of the organization. In the second, competition prevails. This paper provides a comprehensive overview of this extensive literature with the aim of understanding the conditions under which one or the other type of incentive schemes is more desirable for the principal of the organization. To this end, we use a flexible and versatile model capable of addressing a wide range of scenarios characterized by different technologies, information constraints, and behavioral norms.

Contract theory claims that renegotiation prevents attainment of the efficient solution that could be obtained under full commitment. Assessing the cost of renegotiation remains an open issue from an empirical viewpoint. We fit a structural principal-agent model with renegotiation on a set of contracts for urban transport services. The model captures two important features of the industry as only two types of contracts are used (fixed price and cost-plus) and subsidies are greater following a cost-plus contract than following a fixed-price one. We conclude that the welfare gains from improving commitment would be significant but would accrue mostly to operators.