Essays in insurance economics.

Summary Part 1: the exclusivity of contracts. Ch. 1: the role of risk aversion in the rothschild and stiglitz model (1976). We take the rs model, but individuals no longer necessarily behave in the same way with respect to risk. Unusual equilibrium configurations appear: positive profits in equilibrium. multiplicity of equilibria. random insurance. Ch. 2: what information asymmetry? Insurers think they know the risks better than the insureds. We model this idea. To simplify, the reversal of the informational advantage produces an inversion of the equilibrium properties linking coverage to accident probability. Part 2: the absence of contract exclusivity. Ch. 3 : multiple risks and information asymmetry. The specialization of insurers leads to imperfect competition between them. Notions of complementarity and substitutability characterize the different types of equilibria. We analyze the properties of the utility functions that cause them. Ch. 4: Compulsory insurance and anti-selection intensity. Two particularities of life insurance justify a specific modeling: no exclusivity of contracts. the pension is a forced life annuity. Its variations modify the intensity of antiselection. The optimal response to intense antiselection in the private markets may be a decrease in mandatory coverage.