Rationing rule, imperfect information and equilibrium

Summary. The impact of imperfect information on the price setting behaviour of firms is analysed. Specifically, consumers support an information cost to become informed about prices. Firms are endowed with U-shaped average cost curves. If a firm does not supply more than its competitive supply as determined by its marginal cost schedule, then we show that the existence of a pure strategy equilibrium is conditional on the rationing rule employed. If uninformed consumers are served first then the monopoly price is the sole equilibrium whenever consumers' information costs are high enough. Otherwise, a pure strategy equilibrium fails to exist contrary to the results of Salop and Stiglitz (1977) or Braverman (1980) who implicitly suppose that firms supply all the demand at a given price. Received: May 17, 1999; revised version: September 15, 2000     

Credit rationing in a disequilibrium macroeconomic model

This paper develops a four-market disequilibrium macroeconomic model. The model includes the labor, output, bond, and money markets. A number of papers have considered the interactions between the labor and output markets. Fewer papers have considered the financial sectors. This paper is an exploration into the role of financial market disequilibrium (e.g., credit rationing) within a disequilibrium macroeconomic model.     

Communication equilibrium payoffs in repeated games with imperfect monitoring

We characterize the set of communication equilibrium payoffs of any undiscounted repeated matrix-game with imperfect monitoring and complete information. For two-player games, a characterization is provided by Mertens, Sorin, and Zamir (Repeated games, Part A (1994) CORE DP 9420), mainly using Lehrer's (Math. Operations Res. (1992) 175) result for correlated equilibria. The main result of this paper is to extend this characterization to the n-player case. The proof of the characterization relies on an analogy with an auxiliary 2-player repeated game with incomplete information and imperfect monitoring. We use Kohlberg's (Int. J. Game Theory (1975) 7) result to construct explicitly a canonical communication device for each communication equilibrium payoff.     

Credit rationing and capital accumulation with investment and consumption loans revisited

A simple model is developed to evaluate the roles of credit rationing and government policies of financial repression in the process of capital accumulation. In the model, credit rationing on both investment and consumption loans decreases as capital accumulates but increases as the government imposes policies of financial repression to a greater extent. While a reduction in credit rationing on consumption loans impedes capital accumulation, such a reduction on investment loans facilitates it. We find that developing countries may be trapped at a low-capital-stock steady state while developed countries converge to a high-capital-stock steady state. Instead of adopting policies of financial liberalization, interestingly, this paper finds that policies of financial repression may enable developing countries to escape the development trap.     

Cutting the cake with a stranger: Egoism and altruism with imperfect information

This paper investigates the classic divide-and-choose scheme and applies it to a situation in which agents can be either egoists or altruists. Egoism and altruism are defined by looking at the agents' choices as their pieces of cake are permuted. If the divider is informed about the chooser's social attitude, the resulting allocation is fair, but egoists and altruists receive unequal treatment from the application of the rule. With imperfect information about the chooser's social attitude, division is more equal. The results show that, unless the cake is already cut equally, the smaller share increases as the divider's risk aversion increases and as the subjective probability that the chooser is an egoist comes closer to one-half.     

Construction of a state space for interrelated securities with an application to temporary equilibrium theory

Summary We construct an endogenous state space in an exchange economy with possibly infinite horizon. Every period agents trade securities whose payoffs depend on future dividends and asset prices. We reject the perfect foresight assumption on the ground that agents have not only limited knowledge of other individuals' endowments and preferences, but also limited capacity to compute equilibria. We choose instead absence of arbitrage as the principle which allows agents to determine if a system of future prices is possible. We give an alogrithm to compute the set of nonarbitrage prices every period, with both finite and infinite horizon. We then apply this endogenous structure of uncertainty to an infinite horizon temporary equilibrium model.I would like to thank Professor Donald Brown for his constant help and guidance. I have also greatly benefited from helpful discussions with Professors Jacques Drèze, Bernard Dumas, Mordecai Kurz, Carsten Nielsen, Jan Werner, and Ho-Mou Wu.     

Nonuniqueness of solutions in applied general equilibrium models with scale economies and imperfect competition

Summary Since the publication of Harris (1984), applied general equilibrium models with imperfect competition and economies of scale have been extensively used for analyzing international trade and development policy issues. Their attractiveness comes from their offering a natural framework for testing the empirical relevance of numerous propositions from the industrial organization and new trade theoretical literature. Their role in the recent debates on the North American Free Trade Agreement demonstrates their potential importance in policy analysis. This paper warns model builders and users that considerable caution is however needed in interpreting the results and in deriving strong policy conclusion from these models: it is shown that in this generation of applied general equilibrium models, nonuniqueness of equilibria is not a theoretical curiosum, but a potentially serious problem. Disregarding this may lead to dramatically wrong policy appraisals.I am particularly indebted to Tim Kehoe both for his comments and for pinpointing a flaw in a previous version of the paper. I also thank for comments, discussions and/or encouragements Irma Adelman, Len Dudley, Robert Gary-Bobo, Rick Harris, Ed Prescott, Jacques Robert, Herb Scarf, T. N. Srinivasan, and an anonymous referee. Financial support from the FCAR of the Government of Québec and from the SSHRC of the Government of Canada and hospitality from the Federal Reserve Bank of Minneapolis are gratefully acknowledged.     

Asset market equilibrium with short-selling and differential information

We introduce differential information in the asset market model studied by Cheng J Math Econ 20(1):137–152,1991, Dana and Le Van J Math Econ 25(3):263–280,1996 and Le Van and Truong Xuan J Math Econ 36(3): 241–254, 2001. We prove an equilibrium existence result assuming that the economy’s information structure satisfies the conditional independence property. If private information is not publicly verifiable, agents have incentives to misreport their types and therefore contracts may not be executed in the second period. We also show that under the conditional independence property equilibrium contracts are always executable.     

Equilibrium in behavior strategies in infinite extensive form games with imperfect information

Summary We prove the existence of equilibrium in behavior strategies for extensive form games when the game has infinite actions. The result is derived under the assumption that the behavior strategies satisfy the bounded measurability condition. The condition implies that the behavior strategies are restricted to those which can be viewed as continuous functions from the set of initial histories to the space of probability distributions over action spaces which satisfy the Lipschitz bound.I am grateful for the helpful comments of an anonymous referee.     

Consumption and time in economics: prices and quantities in a temporary equilibrium perspective

The main tenet of the paper is that cost-plus non-competitiveprices, while obviously set by firms according to expected marketdemand for their output, can be assumed to be independent ofpossible discrepancies between the expected and the actual demandfor firms' output. The analysis is placed within Hicks's temporaryequilibrium framework, though suggesting an explanation of demandtotally different from Hicks's. It is argued that the rationalefor the independence of prices from actual sales might be foundin Gossen's notion of optimum frequency of consumption.     

Exchange economies with asymmetric information: competitive equilibrium and core

Summary. A replica theorem is shown to hold for exchange economies with asymmetric information. In a replicated exchange economy with asymmetric information the set of all core elements with equal treatment is nonempty, but it is in general only a subset of the core. Nevertheless, the replica theorem and the presence of at least one core element with equal treatment suffice to show existence of a competitive quasi-equilibrium. Conditions on the initial endowments and the communication system are given to ensure that every competitive quasi-equilibrium is a competitive equilibrium.Received: 24 February 2003, Revised: 3 July 2003JEL Classification Numbers: C70, D50, D82.I thank an anonymous referee whose comments led to an improvement of the paper.     

A coalition proof equilibrium for a private information credit economy

Summary This paper examines an economy in which agents with private information about their own productive capabilities seek to raise capital to fund their investment projects. We employ an equilibrium concept which is closely related to Coalition Proof Nash Equilibrium. In equilibrium, all agents who succeed in raising capital (entrepreneurs) are pooled; they all receive the same contract or consumption schedule. Entrepreneurs, however, are separated from those who fail to raise capital. This separation results in productive efficiency for the economy. If the economy has no viable alternative investment opportunity (other than agents' projects) then equilibrium allocations can be supported by a (non-intermediated) securities market. If there is a viable alternative, the equilibrium allocations cannot be supported by a securities market equilibrium. We interpret this case as suggesting the emergence of financial intermedary coalitions.     

Optimal control of an invasive species with imperfect information about the level of infestation

The presence of invasive species is often not realized until well after the species becomes established. Discovering the location and extent of infestation before the invasive species causes widespread damage typically requires intensive monitoring efforts. In this paper, we analyze the problem of controlling an invasive species when there is imperfect information about the degree of infestation. We model the problem as a partially observable Markov decision process in which the decision-maker receives an imperfect signal about the level of infestation. The decision-maker then chooses a management action to minimize expected costs based on beliefs about the level of infestation. We apply this model to a simple application with three possible levels of infestation where the decision-maker can choose to take no action, only monitor, only treat, or do both monitoring and treatment jointly. We solve for optimal management as a function of beliefs about the level of infestation. For a case with positive monitoring and treatment costs, we find that the optimal policy involves choosing no action when there is a sufficiently large probability of no infestation, monitoring alone with intermediate probability values and treatment alone when the probability of moderate or high infestation is large. We also show how optimal management and expected costs change as the cost or quality of information from monitoring changes. With costless and perfect monitoring, expected costs are 20–30% lower across the range of belief states relative to the expected costs without monitoring.     

(Non)optimality of the Friedman rule and optimal taxation in a growing economy with imperfect competition

This paper shows that if capital generates production externality, there exists a wedge between returns to money and to capital, driving the Friedman rule is not optimal. However, in the absence of capital externality, the Friedman rule may be valid even under imperfect competition.     

Aumann-Shapley prices as a scarf social equilibrium

Considered are economies with a single output (a single consumption good) which is produced from l inputs by means of an increasing returns to scale production function f. We show that for quasi-concave and homogeneous functions f of degree r ? 1, the Aumann-Shapley prices constitute a simple Scarf Social Equilibrium. Put differently, Shapley value of the associated atomless game is in the core of that game. Such is not the situation, however, in the more general case when f exhibits increasing returns to scale (but in homogeneous).     

Credit as a Means of Social Provisioning

Depending on one’s vision as to the inherent stability or instability of a market economy, credit either enhances stability or promotes instability. As such, credit either supports or retards social provisioning. Two representative approaches to the role of credit are compared: a DSGE framework and a modern variation of classical political economy. The implications of vision for methodological features are traced. The paper discusses empirical patterns for the American experience since the mid-1970s with respect to their consistency with the visions. If a market economy is inherently unstable, economic and financial stability requires more than monetary policy.     

How equilibrium prices reveal information in a time series model with disparately informed, competitive traders

Accommodating asymmetric information in a dynamic asset pricing model is technically challenging due to the problems associated with higher-order expectations. That is, rational investors are forced into a situation where they must forecast the forecasts of other agents. In a dynamic setting, this problem telescopes into the infinite future and the dimension of the relevant state space approaches infinity. By using the frequency domain approach of Whiteman [Linear Rational Expectations Models: A User's Guide, University of Minnesota Press, Minneapolis, 1983] and Kasa [Forecasting the forecasts of others in the frequency domain, Rev. Econ. Dynam. 3 (2000) 726-756], this paper demonstrates how information structures previously believed to preserve asymmetric information in equilibrium, converge to a symmetric information, rational expectations equilibrium. The revealing aspect of the price process lies in the invertibility of the observed state space, which makes it possible for agents to infer the economically fundamental shocks and thus eliminating the need to forecast the forecasts of others.