The insurance function of contracts

One of the central problems in contract law is to define the frontier between legal and illegal breaches of promises. The distinction between good and bad faith is perhaps the conceptual tool most commonly used to tell one from the other. Lawyers spend a lot of energy trying to frame better definitions of the concepts of good and bad faith based on principles of ethics or justice, but often pay much less attention to theories dealing with the incentives that can engender good faith behavior in contractual relationships. By describing the economics of what Stiglitz defined as “explicit” and “implicit” insurance, I highlight the “insurance function” hidden in any promise with basically no mathematical notation. My aim is to render the subject intelligible and useful to lawyers with little familiarity with economics.

Do insurance defrauders want to be punished?

We analyze a Principal-Agent model of an insurer who faces an adverse selection problem. He is unable to observe if his client has a high risk or a low risk of having an accident. At the underwriting of the contract, the insurer requests the client to declare his risk. After that, the former can costly audit the truthfulness of this announcement. If the audit confirms a false declaration, the insurer is legally allowed to punish the defrauder. We characterize the efRcient contracts when this punishment is bounded from above by a legal restriction. Then, we do some comparative statics on the efRcient contracts and on the agent's utility. The most important result of this paper concerns the legal limit to a defrauder's punishment. We prove that there exists a uni que value of this legal limit that maximizes the expected utility of a high risk type. Facing this particular value of the legal limit to a defrauder's punishment, the insurer will effectively audit a low risk reporto We also show that this particular value increases with the probability of facing a high risk policyholder. Therefore, when this probability is sufRciently high, the nullity of the contract is not enough. From the point of view of a potential defrauder, the law should allow harder sanctions. This is an striking result because the nullity of the contract is a common sanction for this kind of fraud in the USA and in some European countries.