Research Database

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.

A model is constructed where banks provide access to a communication technology which facilitates trade. Bank liabilities may coexist with alternative means of payment in equilibrium, and there exist regions of the parameter space where banking dominates the payments system and where physical exchange media dominate. The model is consistent with some observations concerning the role of the banking system in economic development, and with characteristics of banking crises. In particular, in early stages of economic development: 1) rapid output growth is accompanied by an increasing share of banking in transactions activity and 2) there are recurrent banking "panics" where reductions in measured aggregate output coincide with increases in the use of alternative means of payment relative to bank liabilities. In later stages of development, growth slackens off, the share of banking in the payments system stabilizes and the economy is less likely to be subject to banking panics.

We describe a simple environment in which assets of varying qualities may be used for transactions and consumption. The quality of an asset is known to the seller but not the buyer. We show that this feature can generate a negative relationship between the transactions velocities of assets and their rates of return. We also discuss several versions of Gresham's Law which hold in this environment.

Economic equilibria are usually solutions to fixed point problems rather than solutions to convex optimization problems. This leads to two difficulties that are closely related: First, equilibria may be difficult to compute. Second, a model economy may have more than one equilibrium. This paper explores these issues for a number of stylized economies, including static economies that involve both pure exchange and production, economies that have infinite numbers of goods because of time and uncertainty, and economies with distortionary taxes and externalities. There are numerous numerical examples that illustrate the theory and could serve as test problems for algorithms.

This paper describes methods for conveniently formulating and estimating dynamic linear econometric models under the hypothesis of rational expectations. An econometrically convenient formula for the cross-equation rational expectations restrictions is derived. Models of error terms and the role of the concept of Granger causality in formulating rational expectations models are both discussed. Tests of hypothesis of strict econometric exogeneity along the lines of Sim’s are compared with a test that is related to Wu’s.

Theory typically does not give us reason to believe that economic models ought to be formulated at the same level of time aggregation at which data happen to be available. Nevertheless, this is frequently done when formulating econometric models, with potentially important specification-error implications. This suggests examining the alternatives, one of which is to model in continuous time. The primary difficulty in inferring the parameters of a continuous time model given sampled observations is the “aliasing identification problem.” This paper shows how the restrictions implied by rational expectations sometimes do, and sometimes do not, resolve the problem. This is accomplished very simply in the context of a hypothesis about the term structure of interest rates. The paper confirms and extends results obtained for another example by Hansen and Sargent.

How should a government use the power to commit to ensure a desirable equilibrium outcome? In this paper, I show a misleading aspect of what has become a standard approach to this question, and I propose an alternative. I show that the complete description of an optimal (indeed, of any) policy scheme requires outlining the consequences of paths that are often neglected. The specification of policy along those paths is crucial in determining which schemes implement a unique equilibrium and which ones leave room for multiple equilibria that depend on the expectations of the private sector.