Money as a mechanism in a bewley economy

We investigate the efficiency property of a monetary economy with spot trade. We prove a conjecture that is essentially due to Bewley (Models of Monetary Economics (1980); Econometrica 51 (1983), 1485-504). The gist is that monetary spot trading is nearly efficient ex ante in an environment where very patient agents can accumulate large enough money stocks to be completely self-insured. We also study examples where a nonmonetary mechanism is preferred ex ante to any monetary mechanism in a stationary environment, and where an inflationary monetary mechanism is preferred ex ante to a laissez-faire or deflationary monetary mechanism in an environment with impatient agents.