This paper argues that versions of Samuelson/Cass-Yaari overlapping-generations consumption-loans models ought to be taken seriously as models of fiat money. The case is made by summarizing and interpreting what these models have to say about fiat money and by arguing that these properties are robust in the sense that they can be expected to hold in any model of fiat money. Two of the properties establish the connection between, on the one hand, the existence of equilibria in which value is attached to a fixed stock of fiat money and, on the other hand, the optimality of such equilibria and the nonoptimality of nonfiat-money equilibria. Other properties describe aspects of the tenuousness of monetary equilibria in such models: The nonuniqueness of such equilibria in the sense that there always exists a nonfiat-money equilibrium and the dependence of the existence of the monetary equilibrium on the physical characteristics of other potential assets and on other institutional features like the tax-transfer scheme in effect. Rather than being defects of these models, it is argued that this tenuousness is helpful in interpreting various monetary systems and, in any case, is unavoidable; it will turn up in any good model of fiat money. Still other properties summarize what these models imply about the connection—or, better, lack of such— between fiat money and private borrowing and lending (financial intermediation) and what they imply about country-specific monies.

We study an overlapping generations model which contains a capital good that resembles actual gold. This capital good can he stored without physically depreciating and can, by using other resources, be converted back and forth between gold jewelry which yields utility directly and raw gold which does not.Under the assumption that the three utility-yielding objects—first and second period consumption and jewelry—are gross substitutes, stationary equilibria are shown to exist and are characterized; for some parameter values, there are inefficient equilibria, while for others there are efficient equilibria. Both types can be interpreted as commodity money equilibria.

Cover note : "An earlier version of this paper was presented at a seminar at MIT."

A random matching model with money is used to study the nominal yield on small denomination, bearer, safe, discount securities issued by the government. There is always one steady state with matured securities circulating at par and, for some parameters, another with them circulating at a discount. In the former, a necessary and sufficient condition for a positive nominal yield on not-yet-matured securities is exogenous discriminatory treatment of them by the government. In the latter, the post-maturity discount on securities induces a deeper pre-maturity discount even without such discriminatory treatment.

Until the mid-19th century, shortages of currency were sometimes serious problems. One common response was to prohibit the export of coins. We use a random matching model with indivisible money to explain a shortage and to judge the desirability of a prohibition on the export of coins. The model, although extreme in many regards, represents better than earlier models a demand for outside money and the problems that arise when that money is indivisible. It can also rationalize a prohibition on the export of coins.