Contrats d'assurance multipériodiques et déformation des croyances

Informational asymmetries in insurance markets can be overcome by offering dynamic contracts with experience rating. Such a result has been theoretically demonstrated by Cooper and Hayes (1987) in both monopolistic and competitive environment and is widely used by practitioners. The purpose of this article is to extend the Cooper and Hayes results to take into account the Bayesian updating of beliefs by the insurers. It is motivated by the observed fact that, in health insurance markets, some diseases have higher recurrence probabilities for gene carriers than for non-carriers. We show that, in a two-period monopolistic setting, the updating of beliefs in the second period is detrimental to the high risks that have supported a disease in the first period: these individuals can no longer get full insurance as they did in the Cooper and Hayes setting. When allowing entrants, experience rating is no longer available to supply contracts to high risk individuals. Competition is still beneficial to all individuals but detrimental to the incumbent company that is forced to forsake its profits to keep its clientele.