Information and the Existence of Stationary Markovian Equilibrium
We describe conditions for the existence of a stationary Markovian equilibrium when total production or total endowment is a random variable. Apart from regularity assumptions, there are two crucial conditions: (i) low information—agents are ignorant of both total endowment and their own endowments when they make decisions in a given period, and (ii) proportional endowments—the endowment of each agent is in proportion, possibly random, to the total endowment. When these conditions hold, there is a stationary equilibrium. When they do not hold, such an equilibrium need not exist.
A strategic market game with active bankruptcy
We construct stationary Markov equilibria for an economy with fiat money, one nondurable commodity, countably-many time periods, and a continuum of agents. The total production of commodity remains constant, but individual agents' endowments fluctuate in a random fashion from period to period. In order to hedge against these random fluctuations, agents find it useful to hold fiat money which they can borrow or deposit at appropriate rates of interest; such activity may take place either at a central bank (which fixes interest rates judiciously) or through a money-market (in which interest rates are determined endogenously). We carry out an equilibrium analysis, based on a careful study of Dynamic Programming equations and on properties of the invariant measures for associated optimally-controlled Markov chains. This analysis yields the stationary distribution of wealth across agents, as well as the stationary price (for the commodity) and interest rates (for the borrowing and lending of fiat money). A distinctive feature of our analysis is the incorporation of bankruptcy, both as a real possibility in an individual agent's optimization problem, and as a determinant of interest rates through appropriate balance equations. These allow a central bank (respectively, a money-market) to announce (respectively, to determine endogenously) interest rates in a way that conserves the total money-supply and controls in ation. General results are provided for the existence of such stationary equilibria, and several explicitly solvable examples are treated in detail. Submitted to Journal of Mathematical Economics.
The Use of Qualitative Information in Macro-Economic Policy Analysis
The majority of macro-economic policy models takes for granted that conflicts among objectives can be assessed by means of a tradeoff analysis. Such tradeoffs imply that sacrifices and benefits of various impacts of decisions can be measured on a cardinal scale, so that a conventional macro-economic utility or welfare analysis can be applied.