"Standard theories of insurance, dating from Rothschild and Stiglitz (1976), stress the role of adverse selection in explaining the decision to purchase insurance. In these models, higher risk people buy full or near-full insurance, while lower risk people buy less complete coverage, if they buy...

Rothschild and Stiglitz (1976) show that there need not exist a competitive equilibrium in markets with adverse selection. Building on their framework we demonstrate that externalities between agents - an agent's utility upon accepting a contract depends on the average type attracted by the...