More on money as a medium of exchange

Summary We extend the analysis of Kiyotaki and Wright, who study economies where the commodities that serve as media of exchange (or, commodity money) are determined endogenously. Kiyotaki and Wright consider only steady-state, pure-strategy equilibria; here we allow dynamic and mixed-strategy equilibria. We demonstrate that symmetric, steady-state equilibria in mixed-strategies always exist, while sometimes no such equilibria exist in pure-strategies. We prove that the number of symmetric steady-state equilibria is generically finite. We also show, however, that for some parameter values there exists a continuum of dynamic equilibria. Further, some equilibria display cycles.We thank the National Science Foundation and the University of Pennsylvania Research Foundation for financial support, as well as seminar participants at Stanford University, the London School of Economics, the Econometric Society World Congress in Barcelona, and the Conference on Monetary Theory and Financial Institutions at the Federal Reserve Bank of Minneapolis for their comments or suggestions. Alberto Trejos provided research assistance. The views expressed here are those of the authors and not necessarily those of the Federal Reserve Bank of Minneapolis or the Federal Reserve System.