(Quasi) uniqueness and restoring dynamics of price-dispersion market equilibria under search cost

We study existence, uniqueness and restoring dynamics of price-dispersion equilibria in a market for a homogeneous good. We assume that costs are heterogeneous across participating firms. Specifically, we rely on classical extreme value theory and some recent developments on fee-setting mechanisms to consider cost distributions that are Generalized Pareto. Our analysis provides results on the existence and uniqueness of a price-dispersion equilibrium that link the cost dispersion across firms with the search cost of consumers. If the former is large enough compared to the latter, existence and a form of uniqueness of price-dispersion equilibrium arise. In addition, we propose a natural best-response market dynamics that delivers convergence to the price-dispersion equilibrium, even if the market departs slightly from the Diamond paradox equilibrium. (C) 2018 Elsevier B.V. All rights reserved.