The Tobin effect and the Friedman rule

This paper studies an overlapping generations economy with capital where limited communication and stochastic relocation create an endogenous transactions role for fiat money. We assume a production function with a knowledge externality (Romer-style) that nests economies with endogenous growth (AK form) and those with no long-run growth (the Diamond model). We show that the Tobin effect is always operative. Under CRRA (constant relative risk aversion) preferences, a mild degree of social increasing returns is sufficient (but not necessary) for some positive inflation to dominate zero inflation and for the Friedman rule to be suboptimal, irrespective of the degree of risk aversion.