The Stability of Price Dispersion under Seller and Consumer Learning*

In many markets, it is possible to find rival sellers charging different prices for the same good. Earlier research has attempted to explain this phenomenon by demonstrating the existence of dispersed price equilibria when consumers must make use of costly search to discover prices. We ask whether such equilibria can be learned when sellers adjust prices adaptively in response to current market conditions. With consumer behavior fixed, convergence to a dispersed price equilibrium is possible in some cases. However, once consumer learning is introduced, the monopoly outcome first found by Diamond (Journal of Economic Theory3 (1971), 156–68) is the only stable equilibrium.