Research Database

In a monetary model, it is shown that if there is a unique Pareto inefficient barter equilibrium, then a monetary equilibrium exists when traders are sufficiently patient.

The existence of fixed points for monotone maps on spaces of measures is established. The case of monotone Markov processes is analyzed and a uniqueness and global stability condition is developed. A comparative statics result is presented and the problem of approximation to the invariant distribution is discussed. The conditions of the theorems are verified for the cases of Optimal Stochastic Growth and Industry Equilibrium.

In social science research, household income is widely used as a stand-in for, or approximation to, the economic well-being of households. In a parallel way, income-inequality has been employed as a stand-in for inequality of economic well-being, or for brevity, "economic-inequality." But there is a force in market economies, ones with extensive amounts of monopoly, like the United States, which leads income-inequality to understate economic-inequality. This force has not been recognized before and derives from how monopolies behave. Monopolies, of course, raise prices. This reduces the purchasing power of households, or the value of their income. But monopolies, in fact, reduce the purchasing power of low-income households much more than high-income households. What has not been recognized is that, in many markets, as monopolies raise the prices for their goods, they simultaneously destroy substitutes for their products, low-cost substitutes that are purchased by low-income households. In these markets, then, while high-income households face higher prices, low-income households are shut out of markets, markets for goods and services that are extremely important for their economic well-being. It often leaves them with extremely poor alternatives, and sometimes none, for these products. Some of the markets we discuss include those for housing, financial services, and K-12 public education services. We also discuss markets for legal services, health care services, used durable equipment and repair services. Monopolies that infiltrate public institutions to enrich members, including those in foster care services, voting institutions and antitrust institutions, are also discussed.

This paper focuses on avoidable moral hazard and offers one explanation for limited insurance markets, for closely held firms, and for seemingly simple as opposed to contingent forms of debt. Agents have random endowments of a consumption good which are such that there are gains to trading contingent claims. But any realization of an endowment is known only by its owner unless a verification cost is borne. Contracts in such a setting are said to be consistent if agents submit to verification and honor claims in accordance with prior agreements. The Pareto optimal consistent contracts which emerge are shown to have familiar characteristics.

In this paper, we show that a substantial fraction of the volatility of real exchange rates between developed economies such as Germany, Japan, and the United Kingdom against the US dollar can be accounted for by shocks that affect the prices of primary commodities such as oil, aluminum, maize, or copper. Our analysis implies that existing models used to analyze real exchange rates between large economies that mostly focus on trade between differentiated final goods could benefit, in terms of matching the behavior of real exchange rates, by also considering trade in primary commodities.

We use a model of optimal portfolio choice to measure heterogeneity in risk aversion among households in Thai villages. There is substantial heterogeneity in risk preferences, positively correlated in most villages with alternative estimates based on a full risk-sharing model.