aggregation of information in large cournot markets consider a homogeneous product market where firms have private information about an uncertain demand parameter and compete in quantities we examine the convergence properties of bayesian cournot equilibria as the economy is replicated and conclude that large cournot or almost competitive markets do not aggregate information efficiently except possibly when the production technology exhibits constant returns to scale even in a competitive market there is a welfare loss with respect to the first best outcome due to incomplete information in general nevertheless a competitive market is efficient taking as given the decentralized private information structure of the economy endogenous and costly information acquisition is examined and seen to imply that the market outcome always falls short of the first best level with decreasing returns to scale the results are also shown to be robust to the addition of extra rounds of competition which allows firms to use the information revealed by past prices explicit closed form solutions yielding comparative static results are obtained for models characterized by quadratic payoffs and affine information structures

monitoring moral hazard asymmetric information and risk sharing in procurement contracting this article characterizes the optimal procurement contract for a monopsonistic purchaser who contracts with a risk averse supplier with private information about his costs and who contributes an unobservable effort the costs incurred by the supplier may be uncertain and the purchaser has access to a monitor of costs that may be subject to noise that complicates risk sharing the purchaser prefers to respond to the observability problem with afixed price contract and to respond to the private information problem with a cost plus contract with uncertain costs and a perfect monitor the optimal contract relieves the supplier of some risk and the purchaser prefers that the effort of the supplier be subsidized with deterministic costs and a noisy monitor the optimal contract places risk on the supplier and the purchaser may prefer that the effort of the supplier be taxed procurement of goods and services is an important form of economic exchange that is often characterized by bargaining and contracting rather than by exchange in a competitive market the procurement setting analyzed here corresponds to the case in which the purchaser is a monopsonist who contracts with a single supplier as in the case of the department of defense contracting for the delivery of a military system in such a setting a principalagent model may be a reasonable representation of the relationship between the purchaser and the supplier and the economics of the procurement arrangement is then captured in the contract when the item procured is standardized the relevant information is likely to be common knowledge and risk may be minimal in such a case a fixed price contract may satisfactorily resolve the purchaser s contracting problem in contrast the model considered here is intended to represent the procurement of a nonstandardized item about which information is incomplete costs are uncertain and observability of supplier costs by the purchaser is limited procurement thus is complicated by the conjunction of adverse selection risk sharing and moral hazard problems

self fulfilling mechanisms and rational expectations we introduce a class of communication equilibria which we call self fulfilling mechanisms and show that they provide a game theoretic foundation to rational expectations equilibria letebe an exchange economy with differential information we associate a strategic market game e withe we prove that the allocations achieved through a self fulfilling mechanism in e coincide with the rational expectations equilibrium allocations ine in order to understand how self fulfilment can be realized in a dynamic framework we investigate the relationship between self fulfilling mechanisms in e and nash equilibria of thet stage repeated game t e journal of economic literatureclassification numbers d82 c72

the design of improved parimutuel type information aggregation mechanisms inaccuracies and the long shot bias as disequilibrium phenomena information aggregation mechanisms iams based on parimutuel type betting systems can aggregate information from complex environments however the performance of previously studied systems is imperfect due to possible bluffing strategic timing of decisions and long shot bias this paper demonstrates two modifications of parimutuel systems that improve information aggregation performance by removing disinformation due to strategic behavior and by removing misleading disequilibrium behavior these experiments also demonstrate that long shot bias results from disequilibrium behavior as opposed to being inherent in the psychology of the individuals

municipal bond liquidity and default risk this paper examines the pricing of municipal bonds i use three distinct complementary approaches to decompose municipal bond spreads into default and liquidity components and find that default risk accounts for 74 to 84 of the average spread after adjusting for tax exempt status the first approach estimates the liquidity component using transaction data the second measures the default component with credit default swap data and the third is a quasi natural experiment that estimates changes in default risk around pre refunding events the price of default risk is high given the rare incidence of municipal default and implies a high risk premium

learning about investment risk the effects of structural uncertainty on dynamic investment and consumption abstract we analyze a general equilibrium model where production shocks are unobservable and there is structural uncertainty regarding investment risk because the volatility of the production shocks is unknown higher investment generally accelerates learning on the unknown parameter but the dynamic interaction between learning and investment is complex we quantify this interaction by numerically computing equilibrium investment and consumption in a version of the model calibrated by aggregate us data we find that imperfect observability of productivity shocks by itself does not significantly affect equilibrium investment and consumption but structural uncertainty significantly impacts equilibrium investment and consumption levels

monitoring of performance in organizational contracting the case of defense procurement this paper contains an agency theoretic analysis of procurement contracts in which the government designs optimal linear contracts for a risk averse supplier in the presence of moral hazard private information and imperfect monitoring optimal contracts deviate from first best risk sharing the direction of the deviation depends on the relative severity of the moral hazard and private information problems and on the precision of the monitor in contrast to the usual result in the moral hazard literature the government may in some cases prefer that the effort of the supplier be taxed choice of the precision of the monitor and the categories of costs covered by the monitor are also studied

asymptotic efficiency in large exchange economies with asymmetric information the authors provide conditions on an exchange economy with asymmetric information that guarantee that when the economy is replicated sufficiently often there will be an allocation that is incentive compatible individually rational and nearly efficient the main theorem covers both the case in which aggregate uncertainty remains when the economy is replicated and the case in which replication eliminates aggregate uncertainty in addition the authors demonstrate how their theorem does or does not apply to standard asymmetric information problems such as the buyer s bid double auction problem akerlof s lemons problem and insurance with asymmetric information copyright 1992 by the econometric society

toward a strategic foundation for rational expectations equilibrium a step toward a strategic foundation for rational expectations equilibrium is taken by considering a double auction with n buyers and m sellers with interdependent values and affiliated private information if there are sufficiently many buyers and sellers and their bids are restricted to a sufficiently fine discrete set of prices then generically there is an equilibrium in nondecreasing bidding functions that is arbitrarily close to the unique fully revealing rational expectations equilibrium of the limit market with unrestricted bids and a continuum of agents in particular the large double auction equilibrium is almost efficient and almost fully aggregates the agents information

justifying the first order approach to principal agent problems it is of interest to know when the incentive compatibility conditio n in principal agent problems can be replaced by the condition that the agent s expected utility be stationary in effort the mirrlees rogerson conditions do not work if the principal can observe more than one observable statistic also the mirrlees rogerson assumption that the distribution function of output is convex in the agent s action is unsatisfactory even in the context of the basi c model it is too restrictive the paper presents a suite of conditio ns that are applicable to the multistatistic case and replaces the objectionable convex distribution function assumption copyright 1988 by the econometric society

uncertainty resolution private information aggregation and the cournot competitive limit a cournot model of oligopoly in which otherwise identical firms have private differential information about the common cost of production and a shared but unknown demand curve is examined a bayesian equilibrium of the corresponding game of incomplete information is solved for explicitly and analysed in the symmetric equilibrium different firms produce at different output levels because they have different information because the information individual firms have is random total output and hence market price is also random for any finite number of firms the main result of the paper relates to the asymptotic properties of the equilibrium when the number of firms becomes large under fairly general conditions on the joint distribution of demand and individual firms information about demand the random equilibrium price converges almost surely to a constant in the limit more importantly this price equals the perfectly competitive price in other words in large markets even if no firm knows the true market demand curve and firms are not price takers and do not use price as a signal to improve their information the competitive price will prevail with certainty in the limit aggregate outcomes are as if all firms shared their private information with each other

using cost observation to regulate firms the paper emphasizes the use of accounting data in regulatory or procurement contracts when the supplier 1 has superior information about the cost of the project and 2 invests in cost reduction the main result states that under risk neutrality the supplier announces an expected cost and is given an incentive contract linear in cost overruns this optimal contract moves toward a fixed price contract as the announced cost decreases an investment choice is then introduced and the use of a rate of return regulation is studied

optimal contracting of separable production technologies abstract we analyze the class of agency problems with a risk neutral principal and a risk averse agent in which hidden actions and hidden information on the agent s efficiency are jointly present technological assumptions such as monotonicity of likelihood are no longer sufficient for the optimal contract to be monotone in the sharing rule we show that these regularity properties obtain for the rather wide class of production technologies that are separable in the agent s inputs together with ordinal properties such as monotone differences and affiliation of inputs separability yields the monotonicity in efficiency of the agent s actions and indirect utility

a battle of informed traders and the market game foundations for rational expectations equilibrium abstract potential manipulation of prices and convergence to rational expectations equilibrium is studied in a game without noise traders informed players with initially long and short positions bulls and bears seek to manipulate consumer expectations in opposite directions in equilibrium period 1 prices reveal the state so manipulation is unsuccessful bears and uninformed consumers sell up to their short sale limits in period 1 bulls buy in period 1 but receive arbitrage losses when the number of bulls and bears approaches infinity the equilibrium converges to the ree without short sale constraints there is a non revealing equilibrium but no revealing equilibrium

countervailing incentives in agency problems abstract we analyze countervailing incentives in agency problem countervailing incentives exist when the agent has an incentive to understate his private information for some of its realizations and to overstate it for others when countervailing incentives arise pooling generally characterizes the equilibrium contract furthermore performance is distorted both above and below efficient levels in addition the agent s rents generally increase with the realization of his private information over some ranges and decrease over other ranges we demonstate that the creation of countervailing incentives can enhance aggregate welfare

information aggregation in a large multi stage market game abstract a three stage market game mechanism is devised that is simple actions are quantities and outcomes are determined by arithmetic operations that do not depend on details of the economy and achieves efficiency in a two divisible good pure exchange setting with potential information aggregation after an entry stage agents make offers which are provisional for all but a small randomly selected group then those offers are announced and everyone else makes new offers with payoffs determined by a shapley shubik market game for a finite and large number of players there exists an almost ex post efficient equilibrium conditions for uniqueness are also provided

what can we learn from simulating a standard agency model abstract for typical parametrizations of the standard bell journal of economics 10 1979 74 agency model this paper demonstrates that the set of first order conditions characterizing the optimal contract can be reduced to a single equation a problem of investment financing under moral hazard is used to illustrate the reduced form equation s usefulness in quantitative applications when the agent has cara preferences over consumption it is shown that any exogenous limit on the penalties for low output is always binding

default risk cannot explain the muni puzzle evidence from municipal bonds that are secured by u s treasury obligations fama 1977 and miller 1977 predict that one minus the corporate tax rate will equate after tax yields from comparable taxable and tax exempt bonds empirical evidence shows that long term tax exempt yields are higher than theory predicts two popular explanations for this empirical puzzle are that relative to taxable bonds municipal bonds bear more default risk and include costly call options i study u s government secured municipal bond yields which are effectively default free and nonmalleable these municipal yields display the same tendency to be too high i conclude that differential default risk and call options do not explain the municipal bond puzzle article published by oxford university press on behalf of the society for financial studies in its journal the review of financial studies

informational size and incentive compatibility we examine a general equilibrium model with asymmetrically informed agents the presence of asymmetric information generally presents a conflict between incentive com patibility and pareto efficiency we present a notion of informational size and show that the conflict between incentive compatibility and efficiency can be made arbitrarily small if agents are of sufficiently small informational size the incompatibility of pareto efficiency and incentive compatibility is a central theme in economics and game theory the issues associated with this incompatibility are particularly important in the design of resource allocation mechanisms in the presence of asymmetrically informed agents where the need to acquire information from agents in order to compute efficient outcomes and the incentives agents have to misrepresent that information for personal gain come into conflict despite a large literature that focuses on these issues there has been little work aimed at understanding those situations in which informational asymmetries are quantitatively important virtually every transaction is characterized by some asymmetry of information any investor who buys or sells a share of stock generally knows something rel evant to the value of the share that is not known to the person on the other side of the transaction in order to focus on more salient aspects of the problem many models rightly ignore the incentive problems associated with informa tional asymmetries in the belief that for the problem at hand agents are infor mationally small however few researchers have investigated the circumstances under which an analysis that ignores these incentive problems will yield results similar to those obtained when these problems are fully accounted for in this paper we study a class of mechanism design problems our goal is to formalize informational size in a way that when agents are informationally small 1 early versions of this paper circulated under the titles informational smallness and pareto effi ciency and informational smallness and incentive compatibility we thank jacques cremer dean foster andreu mas colell stephen morris david schmeidler and particularly faruk gul for help ful conversations and rajiv vohra for a very careful reading we also thank the numerous partici pants in seminars at which this paper was presented for helpful comments we also thank an editor and the referees for very helpful comments and thank ichiro obara for pointing out an error in an earlier version postlewaite gratefully acknowledges support from the national science foundation

rationalizability learning and equilibrium in games with strategic complementarities we study a rich class of noncooperative games that includes models of oligopoly competition macroeconomic coordination failures arms races bank runs technology adoption and diffusion r d competition pretrial bargaining coordination in teams and many others for all these games the sets of pure strategy nash equilibria correlated equilibria and rationalizable strategies have identical bounds also for a class of models of dynamic adaptive choice behavior that encompasses both best response dynamics and bayesian learning the players choices lie eventually within the same bounds these bounds are shown to vary monotonically with certain exogenous parameters we study the class of noncooperative supermodular games introduced by topkis 1979 and further analyzed by vives 1985 1989 who also pointed out the importance of these games in industrial economics supermodular games are games in which each player s strategy set is partially ordered the marginal returns to increasing one s strategy rise with increases in the competitors strategies so that the game exhibits strategic complementarity 2 and if a player s strategies are multidimensional marginal returns to any one com ponent of the player s strategy rise with increases in the other components this class turns out to encompass many of the most important economic applications of noncooperative game theory in macroeconomics diamond s 1982 search model and bryant s 1983 1984 rational expectations models can be represented as supermodular games in each of these models more activity by some members of the economy raises the returns to increased levels of activity by others in oligopoly theory some models of bertrand oligopoly with differentiated products qualify as supermodu lar games in these games when a firm s competitors raise their prices the marginal profitability of the firm s own price increase rises a similar structure is present in games of new technology adoption such as those of dybvig and spatt 1983 farrell and saloner 1986 and katz and shapiro 1986 when more users hook into a communication system or more manufacturers adopt an interface standard the marginal return to others of doing the same often rises similarly in some specifications of the bank runs model introduced by diamond and dybvig 1983 when more depositors withdraw their funds from a bank it is more worthwhile for other depositors to do the same in the warrant exercise

portfolio performance and agency the evaluation and compensation of portfolio managers is an important problem for practitioners optimal compensation will induce managers to expend eort to generate information and to use it appropriately in an informed portfolio choice our general model points the way towards analysis of optimal performance evaluation and contracting in a rich model optimal contracting in the model includes an important role for portfolio restrictions that are more complex than the sharing rule the agent s compensation gives the agent approximately to a benchmark return plus an incentive fee equal to a portfolio measure that is approximately the excess of return above the benchmark this measure is often used by practitioners but is simpler than the jensen measure and other measures commonly recommended in the academic literature in addition to the excess return above the xed benchmark the manager is given some additional incentive to take a position that deviates from the benchmark to remove an incentive to tend towards being a closet indexer ecient contracting involves restrictions on what portfolio strategies can be pursued and prior communication of the information gathered

credit swap valuation this review of the pricing of credit swaps a form of derivative security that can be viewed as default insurance on loans or bonds begins with a description of the credit swap contract turns to pricing by reference to spreads over the risk free rate of par floating rate bonds of the same quality and then considers model based pricing the role of asset swap spreads as a reference for pricing credit swaps is also considered

an analysis of the principal agent problem most analyses of the principal agent problem assume that the principal chooses an incentive scheme to maximize expected utility subject to the agent s utility being at a stationary point an important paper of mirrlees has shown that this approach is generally invalid we present an alternative procedure if the agent s preferences over income lotteries are independent of action we show that the optimal way of implementing an action by the agent can be found by solving a convex programming problem we use this to characterize the optimal incentive scheme and to analyze the determinants of the seriousness of an incentive problem

a simple model of the taxable and tax exempt yield curves i examine the anomalous behavior of the taxable and tax exempt yield curves long municipal yields appear too high relative to the equivalent after tax yield that can be earned in treasury or corporate bonds i discuss existing explanations of the problem and propose a simple model that relates the yields of taxable bonds to the yield curve for par tax exempts the ratio of the tax exempt yield to the taxable yield increases with maturity in the model so it is consistent with observed phenomena such as inverted yield curves for taxables and contemporaneous rising yield curves for tax exempts statistical and descriptive comparisons between the yields predicted by the model and observed yields on par bonds that the model has some promise in explaining the apparent anomalies in the behaviors of the two yield curves article published by oxford university press on behalf of the society for financial studies in its journal the review of financial studies

efficiency of large double auctions we consider large double auctions with private values values need be neither symmetric nor independent multiple units may be owned or desired participation may be stochastic we introduce a very mild notion of a little independence we prove that all nontrivial equilibria of auctions that satisfy this notion are asymptotically efficient for any alpha 0 inefficiency disappears at rate 1 n 2 alpha