Asymmetric information in a competitive market game: Reexamining the implications of rational expectations

Summary. We examine price formation in a simple static model with asymmetric information, an infinite number of risk neutral traders and no noise traders. Here we re-examine four results associated with rational expectations models relating to the existence of fully revealing equilibrium prices, the advantage of becoming informed, the costly acquisition of information, and the impossibility of having equilibrium prices with higher volatility than the underlying fundamentals. Received: August 27, 1997; revised version: February 11, 1998     

Informational efficiency with ambiguous information

This paper proves the existence of fully revealing rational expectations equilibria for almost all sets of beliefs when investors are ambiguity averse and have preferences that are characterized by Choquet expected utility with a convex capacity. The result implies that strong-form efficient equilibrium prices exist even when many investors in the market make use of information in a way that is substantially different from traditional models of financial markets.     

Incomplete financial markets and differential information

We provide a model of an incomplete markets economy where private restrictions on consumption are interpreted as lack of information. We prove existence of an equilibrium where agents are unable to infer any additional information from prices. When assets are nominal, these non-enlightening equilibrium prices result in a reduction of the degree of real indeterminacy.     

Information Revelation and Market Incompleteness

This paper introduces a theory of market incompleteness based on the information transmission role of prices and its adverse impact on the provision of insurance in financial markets. We analyse a simple security design model in which the number and payoff of securities are endogenous. Agents have rational expectations and differ in information, endowments, and attitudes toward risk. When markets are incomplete, equilibrium prices are typically partially revealing, while full relevation is attained with complete markets. The optimality of complete or incomplete markets depends on whether the adverse selection effect (the unwillingness of agents to trade risks when they are informationally disadvantaged) is stronger or weaker than the Hirshleifer effect (the impossibility of trading risks that have already been resolved), as new securities are issued and prices reveal more information. When the Hirshleifer effect dominates, an incomplete set of securities is preferred by all agents, and generates a higher volume of trade.     

Dynamic signaling and market breakdown

We consider the effects a public revelation of information (e.g. rating, grade) has on trading in a dynamic signaling model. Competing buyers offer prices to a privately informed seller who can reject them and delay trade. Delay is costly and the seller has no commitment to its duration. The external public information allows for signaling in equilibrium. More interestingly, we characterize the dynamics of trade and prices. If signals are noisy, no trade takes place just before the revelation of external information. If signals are fully revealing, then trade occurs even close to revelation, however, transaction prices are discontinuous.     

Trade and revelation of information

We consider an economy with asymmetric information and two types of agents, fully informed and uninformed. Uninformed agents update their information observing equilibrium prices and the equilibrium levels of other agents’ excess demand. We show that, for a generic set of economies, there are rational expectations equilibria which are partially revealing on an open, dense set of signals of positive Lebesgue measure, provided that the dimension of the signal space is sufficiently larger than the dimension of the commodity space.     

Stationary Markov equilibria for overlapping generations

Summary.  At a stationary Markov equilibrium of a Markovian economy of overlapping generations, prices at a date-event are determined by the realization of the shock, the distribution of wealth and, with production, the stock of capital. Stationary Markov equilibria may not exist; this is the case with intra-generational heterogeneity and multiple commodities or long life spans. Generalized Markov equilibria exist if prices are allowed to vary also with the realization of the shock, prices and the allocation of consumption and production at the predecessor date-event. (Stationary) Markov -equilibria always exist; as allocations and prices converge to equilibrium prices and allocations that, however, need not be stationary.Received: 2 March 2004, Revised: 2 April 2004, JEL Classification Numbers:   D50, D52, D60, D80, D90.Correspondence to: Felix KublerWe thank participants in seminars in Athens and Lund, at Penn, at IMPA and at Stanford, the 2002 CEME (NBER) General Equilibrium Conference and the 2002 SED meetings, and especially Martin Hellwig, George Mailath and an anonymous referee for very helpful comments.     

Equilibrium existence and approximation of regular discontinuous games

Many conditions have been introduced to ensure equilibrium existence in games with discontinuous payoff functions. This paper introduces a new condition, called regularity, that is simple and easy to verify. Regularity requires that if there is a sequence of strategies converging to s* such that the players’ payoffs along the sequence converge to the best-reply payoffs at s*, then s* is an equilibrium. We show that regularity is implied both by Reny’s better-reply security and Simon and Zame’s endogenous sharing rule approach. This allows us to explore a link between these two distinct methods. Although regularity implies that the limits of e{\epsilon}-equilibria are equilibria, it is in general too weak for implying equilibrium existence. However, we are able to identify extra conditions that, together with regularity, are sufficient for equilibrium existence. In particular, we show how regularity allows the technique of approximating games both by payoff functions and space of strategies.     

Experts against adverse selection: A note on the existence of equilibrium with costly appropriable information

The existence of competitive equilibrium in Laffont's (J. Econ. Theory10 (1975)) model of adverse selection with costly information is studied. The existence of an equilibrium with finite prices is demonstrated without unusual restrictions on preferences or the technology of information production. This is made possible by changing the way in which the behaviour of information producing agents is modelled, and allowing for some public information.     

Economic Potential of Biomass Based Fuels for Greenhouse Gas Emission Mitigation

Use of biofuels diminishes fossil fuelcombustion thereby also reducing net greenhousegas emissions. However, subsidies are neededto make agricultural biofuel productioneconomically feasible. To explore the economicpotential of biofuels in a greenhouse gasmitigation market, we incorporate data onproduction and biofuel processing for thedesignated energy crops switchgrass, hybridpoplar, and willow in an U.S. AgriculturalSector Model along with data on traditionalcrop-livestock production and processing, andafforestation of cropland. Net emissioncoefficients on all included agriculturalpractices are estimated through crop growthsimulation models or taken from the literature. Potential emission mitigation policies ormarkets are simulated via hypothetical carbonprices. At each carbon price level, theAgricultural Sector Model computes the newmarket equilibrium, revealing agriculturalcommodity prices, regionally specificproduction, input use, and welfare levels,environmental impacts, and adoption ofalternative management practices such asbiofuel production. Results indicate no rolefor biofuels below carbon prices of $40 perton of carbon equivalent. At these incentivelevels, emission reductions via reduced soiltillage and afforestation are more costefficient. For carbon prices above $70,biofuels dominate all other agriculturalmitigation strategies.     

Information aggregation in financial markets with career concerns

What are the equilibrium features of a dynamic financial market in which traders care about their reputation for ability? We modify a standard sequential trading model to include traders with career concerns. We show that this market cannot be informationally efficient: there is no equilibrium in which prices converge to the true value, even after an infinite sequence of trades. We characterize the most revealing equilibrium of this game and show that an increase in the strength of the traders' reputational concerns has a negative effect on the extent of information that can be revealed in equilibrium but a positive effect on market liquidity.     

Computing uniformly optimal strategies in two-player stochastic games

We provide a computable algorithm to calculate uniform ε-optimal strategies in two-player zero-sum stochastic games. Our approach can be used to construct algorithms that calculate uniform ε-equilibria and uniform correlated ε-equilibria in various classes of multi-player non-zero-sum stochastic games.     

大宗交易制度:机构投资者的特殊安排

金融市场微观结构理论认为交易制度对于金融资产价格形成作用重大，目前的市场主体结构需要不同于正常规模的交易制度。巨大的市场影响成本、搜寻成本和延迟成本，对于信息披露的特殊要求，使得机构投资者选择大宗交易制度。对于大宗交易制度降低透明度引起的不公平，应以有效的监管予以弥补。     

Stochastic equilibria with incomplete financial markets

We demonstrate the existence of equilibria with incomplete financial markets for stochastic economies whose information structure is given by an event tree, restricting attention to purely financial securities, those paying in units of account (e.g., “dollars”). Financial markets may be incomplete: some consumption streams may be impossible to obtain by any trading strategy. Securities may be individually precluded from trade at arbitrary states and dates. Sufficient conditions for the existence of stochastic equilibria are: continuous, convex, strictly monotonic preferences and strictly positive aggregate endowments. These conditions are weakened. A corollary states that any regime of security prices precluding arbitrage can be embedded in an equilibrium.     

A wavelet decomposition approach to crude oil price and exchange rate dependence

This paper studies the relationship between oil prices and US dollar exchange rates using wavelet multi-resolution analysis. We characterized the oil price–exchange rate relationship for different timescales in an attempt to disentangle the possible existence of contagion and interdependence during the global financial crisis and analyze possible lead and lag effects. For crude oil prices and a range of currencies, we show that oil prices and exchange rates were not dependent in the pre-crisis period; however, we did find evidence of contagion and negative dependence after the onset of the crisis. Additionally, we found that oil prices led exchange rates and vice versa in the crisis period but not in the pre-crisis period. These findings have important implications for risk management, monetary policies to control oil inflationary pressures and fiscal policy in oil-exporting countries.     

The generic existence of rational expectations equilibrium in the higher dimensional case

The study of the generic existence of rational expectations equilibrium has concentrated on three cases, according to whether the space of “states of private information” has dimension less than, equal to, or greater than the price space. Previous results have shown that in the first case fully revealing equilibria exist generically and in the second case there are open sets of environments with no equilibrium. This paper shows that in the third case there is a residual set of environments which permits equilibria which are arbitrarily close to fully revealing.     

Intra‐Week Price Patterns in the Housing Market*

In this paper, I demonstrate the existence of city‐specific intra‐week price patterns in the Norwegian housing market. I use a data set with exact sell dates to show that sell prices are higher on certain days. Using ask prices and observations on repeat sales in fixed‐effect models, I seek to control for composition effects and unobserved heterogeneity. The intra‐week price patterns are shown to be associated with patterns in the frequency of public‐showing days. I argue that the findings are consistent with optimizing agents acting on new information.     

The Informational Role of Prices*

We consider a dominant firm with a competitive fringe in order to investigate the informational role of prices. The fringe is necessary for the existence of a unique, fully revealing equilibrium, in which the price reveals the quality of the good to uninformed buyers. A higher price triggers more sales on the part of the competitive fringe, reducing both residual demand and profits. We find that a larger share of uninformed buyers increases the price and reduces the quantity sold by the dominant firm, but increases the quantity sold by the competitive fringe. This, in turn, reduces consumer surplus and welfare.     

The Dynamics of Markups and Inventories in Retailing Firms

This paper is concerned with the interaction between price and inventory decisions in retailing firms and its implications for the dynamics of markups and the existence of sales promotions. We consider a model where a monopolistically competitive retailer decides price and inventories, and assumes lump-sum costs when placing orders or changing nominal prices. In this model, the existence of stockout probabilities and fixed ordering costs generate a cyclical price behaviour characterized by long periods without nominal price changes and short periods with very low prices ( i.e. sales promotions). We estimate this model using a unique longitudinal dataset with information about retail and wholesale prices, inventories, orders, and sales for several brands in a supermarket chain. Based on the estimated model we perform several counterfactual experiments that show the important role that inventories and fixed ordering costs play in the dynamics of retail prices and the frequency of sales promotions in this dataset.     

Informed manipulation

In asymmetric information models of financial markets, prices imperfectly reveal the private information held by traders. Informed insiders thus have an incentive not only to trade less aggressively but also to manipulate the market by trading in the wrong direction and undertaking short-term losses, thereby increasing the noise in the trading process. In this paper we show that when the market faces uncertainty about the existence of the insider in the market and when there is a large number of trading periods before all private information is revealed, long-lived informed traders will manipulate in every equilibrium.