Exclusionary equilibria in health-care markets

We have demonstrated that when providers of health insurance are perceived to be differentiated by consumers, circumstances may arise under which they find it advantageous to restrict the set of health-care providers that they approve to their customers. Even if all health-care providers are equally qualified and efficient, payers may choose to contract with a selected subset of them in order to secure more favorable contract terms. Moreover, in a concentrated health-care market that consists of two health insurance companies (payers) and two health-care providers (hospitals), both payers may choose to contract with only one of the hospitals while excluding the other completely from the market. When consumers' valuation of an extended choice of providers is small in comparison with the extent of differentiation that exists between the payers, such an exclusionary outcome is the unique equilibrium of the game.