Anonymous Markets and Monetary Trading∗

We study infinite-horizon monetary economies characterized by trading frictions that originate from random pairwise meetings, and commitment and enforcement limitations. We prove that introducing occasional trade in “centralized markets” opens the door to an informal enforcement scheme that sustains a non-monetary efficient allocation. All is required is that trading partners’ be patient and their actions be observable. We then present a matching environment in which trade may occur in large markets and yet agents’ trading paths cross at most once. This allows the construction of models in which infinitely-lived agents trade on competitive markets in which money plays an essential role.