Non-implementation of rational expectations as a perfect Bayesian equilibrium

Summary. We point out several conceptual difficulties of the rational expectations equilibrium concept. In particular we show that such an equilibrium need not be incentive compatible and need not be implementable as a perfect Bayesian equilibrium . A comparison of rational expectations equilibria with the private core is also provided. We conclude that the private core is a more appropriate concept to capture the idea of contracts under asymmetric information.Received: 15 December 2003, Revised: 18 November 2004, JEL Classification Numbers: C71, C72, D5, D82. Correspondence to: Nicholas C. YannelisWe wish to thank Dr A. Hadjiprocopis for his invaluable help with the implementation of Latex in a Unix environment.     

Bilateral Oligopoly,Private Information,and Pollution Permit Markets

We analyze the effects of strategic behavior and private information in pollution permit markets in which all firms have market power. The market is characterized by supply-function equilibria. Firms submit net supplies for permits and a market maker determines the market-clearing price. Net supplies depend on abatement cost functions, which in turn depend on private information parameters. We calculate the increase in aggregate abatement costs due to strategic behavior and private information and show that private information attenuates the effects of strategic behavior.      

Existence of Edgeworth equilibria for economies with asymmetric information

We analyze a general equilibrium model with asymmetrically informed agents. A basic and well-known consequence of asymmetric information is the failure of equal treatment property. Despite of this, we show that in every replica economy a private core allocation, which treats agents of the same type equally, exists. This result is provided in the framework of two different models, with and without expectations, and it suffices to guarantee in both cases the existence of a private Edgeworth equilibrium. The author is grateful to an anonymous referee for his/her careful reading and helpful comments and acknowledges support by Research Grant no. 2006132713-005 (Ministero Italiano dell’Università e della Ricerca).     

Information transmission and inefficient lobbying

In a seminal paper, Grossman and Helpman (1994) introduced a framework to understand how lobbying influences the choice of import/export tariffs. In this paper we extend their analysis and assume that lobbies have private information to analyze the effects of information transmission in a Grossman and Helpman lobby game. Information transmission leads to two agency costs. One refers to the cost of signaling and the other to the cost of screening the lobby's competitiveness. The signaling cost reduces distortions resulting from the screening cost. On the other hand, distortions from the screening cost enhance the signaling cost. The two combined effects generate more distortions in the political game than each effect separately. Tariff protection and lobbies' rents are lower than those found in Grossman and Helpman's truthful equilibrium. Therefore, information transmission may improve welfare through the reduction of rent-seeking activities.     

Bargaining over a Common Good with Private Information*

Consider two agents who make sequential claims on a common good, receiving their respective claims only if these are compatible. We let the first mover be privately informed about the size of the good. Conventional theory predicts multiple equilibria, and the intuitive criterion predicts that the first player claims the entire good. Our experimental results reject the intuitive criterion. Private information reduces the claim and the profit of the first mover. However, we cannot reject that the subjects play according to a perfect Bayesian equilibrium (PBE). Most subjects play according to a PBE, and almost all successful coordination occurs at the even split.     

Characterization and incentive compatibility of Walrasian expectations equilibrium in infinite dimensional commodity spaces

Summary. We consider a differential information economy with infinitely many commodities and analyze the veto power of the grand coalition with respect the ability of blocking non-Walrasian expectations equilibrium allocations. We provide two different Walrasian expectations equilibrium equivalence results. First by perturbing the initial endowments in a precise direction we show that an allocation is a Walrasian expectations equilibrium if and only if it is not privately dominated by the grand coalition. The second characterization deals with the fuzzy veto in the sense of Aubin but within a differential information setting. This second equivalence result provides a different characterization for the Walrasian expectations equilibrium and shows that the grand coalition privately blocks in the sense of Aubin any non Walrasian expectations equilibrium allocation with endowment participation rate arbitrarily close to the total initial endowment participation for every individual. Finally, we show that any no free disposal Walrasian expectations equilibria is coalitional Bayesian incentive compatible. Since the deterministic Arrow-Debreu-McKenzie model is a special case of the differential information economy model, one derives new characterizations of the Walrasian equilibria in economies with infinitely many commodities.Received: 29 October 2003, Revised: 24 February 2004, JEL Classification Numbers: D51, D82, D11. Correspondence to: Emma Moreno-GarcíaThe authors are grateful to an anonymous referee for his/her careful reading and helpful comments and suggestions.C. Hervés and E. Moreno acknowledge support by Research Grant BEC2000-1388-C04-01 (Ministerio de Ciencia y Tecnología and FEDER); and support by the Research Grant SA091/02 (Junta de Castilla y León).     

民间资本供求与民营企业融资:对陕西的实证分析

本文建立在调研和有关资料基础上对陕西现实及潜在的民间资本供求进行测算分析,从总量和结构等方面实证了民间资本供给充足、而民营经济对民间资本的需求欲望非常强烈这一结论,要解除民间资本供求的市场失灵现象,就必须构建以"民资、民用、民管"为原则的内生性融资机制,建立社区民间金融管理组织和社区民间金融市场,选择内生性融资方式,创新其融资产品,实现民间资本供给与民营经济对其需求的有效对接.     

Strategic Behavior,Private Information,and Decentralization in the European Union Emissions Trading System

In the European Union Emissions Trading System, the supply of carbon permits is determined in a decentralized manner by Member States. Alternatively, the supply could be determined by an EU central authority. We analyze whether decentralization leads to lower total abatement costs under various assumptions about the behavior of Member States and the privacy of information about their abatement costs. If Member States do not behave strategically, then decentralization is preferred, regardless of whether abatement costs are private information. If the Member States behave strategically, then decentralization may or may not be preferred, depending on the degree of uncertainty about abatement cost parameters, the variation in emission endowments, and the number of Member States.     

The life insurance market: Asymmetric information revisited

This paper finds evidence for the presence of asymmetric information in the life insurance market, a conclusion contrasting with the existing literature. In particular, we find a significant and positive correlation between the decision to purchase life insurance and subsequent mortality, conditional on risk classification. Individuals who died within a 12-year time window after a base year were 19% more likely to have taken up life insurance in that base year than were those who survived the time window. Moreover, as might be expected when individuals have residual private information, we find that the earlier an individual died, the more likely she was to have initially bought insurance. The primary factor driving the difference between our and the prior literature's findings is that we focus on a sample of potential new buyers, rather than on the entire cross section, to address the sample selection problem induced by potential mortality differences between those with and those without coverage.     

Information acquisition in auctions: Sealed bids vs. open bids

This paper studies the incentives of a bidder to acquire information in an auction when her information acquisition decision is observed by the other bidders before bidding. Our results show that the sealed bid (second price) auction may induce more information acquisition about a common component of the value than the open (English) auction but less about the private component of the value. Moreover, we show that more information about the private value and less information about the common value may improve efficiency and revenue. Consequently, our results suggest new arguments in favor of the open auction.     

基于R2的中国股市私有信息套利分析

R2在统计学中是模型对实证数据拟合优度的度量指标,自Roll(1988)R2开创性研究后,R2在金融学研究中得以更为广泛地度量应用。遗憾的是,在对Roll(1988)进一步研究中所进行的大胆理论延伸,造成了R2在金融领域度量标准在经济意义上的混乱。本文通过对现有文献的梳理、解读和评价,采用逻辑演绎的方法推导出R2可作为私有信息套利的度量指标。本文对2005—2007年上证180中的140只股票进行实证研究表明:(1)几乎所有股票都存在着私有信息套利,且60%的股票私有信息套利程度较深。(2)通过面板模型进一步分析了影响私有信息套利的主要变量,发现上市公司第一大股东持股比例、限售股比例与R2存在显著的负相关关系,机构投资者持股比例、股权分置改革完成时间、公司规模与R2存在正相关关系。     

The measure of blocking coalitions in differential information economies

We provide an evaluation of the measure of privately blocking coalitions in differential information economies. In the case of atomless economies, it is proved that for a Pareto optimal allocation that is not a Walrasian expectations equilibrium, to any symmetric profile there corresponds a ball such that "almost half” of the profiles it contains are privately blocking. Analogous results are proved in the case of finite differential information economies for generalized coalitions and social coalition structures. From a different point of view, the paper can be considered as a contribution showing private core equivalence theorems under restrictions on coalition formation. We thank an anonymous referee for observations and comments improving an earlier version of the present paper.     

Market games with asymmetric information: the core

This paper concerns cores of economies with asymmetric information. Alternative definitions of the information available to traders in coalitions and the cooperative games they generate are analyzed. An important technical result states that such NTU games in characteristic function form are well defined. Properties of various cores with asymmetric information are examined. Sufficient conditions on information sharing rules are provided for the induced games to be totally balanced or balanced, so that their cores are nonempty. Incentive compatibility issues are considered. Finally, a perspective on this research area is provided.     

No-arbitrage Equilibria with Differential Information: An Existence Proof

On the example of a pure exchange financial economy with two periods incomplete nominal-asset markets and differential information of the adverse selection’s type, Cornet-De Boisdeffre (J Math Econ 38:393-410, 2002) introduced refined concepts of no-arbitrage prices and equilibria, which extended to the asymmetric information setting the classical concepts of the symmetric information literature. We now assess existence issues and extend a standard property of symmetric information models. Namely, we prove that a no-arbitrage equilibrium always exists, as long as financial markets preclude arbitrage, under the same standard conditions, whether agents have symmetric or asymmetric information.     

Private value perturbations and informational advantage in common value auctions

We analyze the value of being better informed than one's rival in a two bidder, second price common value auction. Standard models of these auctions do not pin down relative bidding postures, but we show that by adding small amounts of private value information, a unique equilibrium can be restored. Additional common value information affects a bidder's payoff both directly, by increasing his information rent, and indirectly, by shifting the relative bidding posture of his opponent. Although the latter effect need not be positive, we establish broad conditions under which bidders with more information do better than their rivals. We turn to information acquisition and release and show that the desire to influence relative bidding postures can lead sellers to create new information rents (by releasing information privately to only one bidder) and bidders to forego information rents (instead choosing to gather information that a rival already has).     

信息披露机制对私营企业融资决策的影响

本文通过实证研究检验了一个有关私营企业融资决策的假说 ,即如果不考虑资本市场资金拆借的利息成本和执行成本 ,那么影响私营企业融资决策的主要因素将是各层级资本市场要求的信息披露机制。检验结果支持了本文的论点 ,即越是高层级的资本市场 ,要求私营企业披露的有关经营方面的信息就越多 ,而在现阶段 ,经营信息的披露会给私营企业带来潜在的经营风险。因此 ,私营企业更多地依赖低层级资本市场提供的资金支持     

An extensive form interpretation of the private core

Summary. The private core of an economy with differential information, (Yannelis (1991)), is the set of all state-wise feasible and private information measurable allocations which cannot be dominated, in terms of ex ante expected utility functions, by state-wise feasible and private information measurable net trades of any coalition. It is coalitionally Bayesian incentive compatible and also takes into account the information superiority of an individual. We provide a noncooperative extensive form interpretation of the private core for three person games. We construct game trees which indicate the sequence of decisions and the information sets, and explain the rules for calculating ex ante expected payoffs. In the spirit of the Nash programme, the private core is thus shown to be supported by the perfect Bayesian equilibrium of a noncooperative game. The discussion contributes not only to the development of ideas but also to the understanding of the dynamics of how coalitionally incentive compatible contracts can be realized. Received: July 21, 2000; revised version: January 16, 2001     

中国公众投资者信息需求之探索性研究

公众投资者在获取上市公司信息方面通常处于弱势地位。本文旨在通过问卷调查 ,研究中国公众投资者信息需求的特点 ,对目前信息供给状况的态度 ,以及他们与国外公众投资者在信息需求和决策变量选择上是否存在差异等。研究发现 ,信息的真实性、及时性和充分披露是我国公众投资者认为最重要的质量特征。为此 ,建议通过采取完善与信息披露相关的法律法规、加强监管、严厉处罚等手段 ,促进上市公司及会计师事务所等中介机构披露真实、及时的信息 ;鼓励上市公司更多地作出诸如公司未来收益潜力预测等前瞻性信息的自愿披露。     

The Quantitative Law of Network Information Growth

Based on the assumptions of ＂information transfer＂ and ＂information creation＂, this paper educes the multiplied growth mechanism of network information： that the gross quantity of network information （Im） is about n times as much as the quantity of real network information （Ir）. According to this theoretical model, we give a uniform explanation to all kinds of information growth models in existence, and put forward some proposals, such as ＂forbidding information transfer＂ and ＂building up the central information base＂, to control the repeated information flooding on the network and facilitate the full use of network information.     

Entitling the Pollutee: Liability versus Standard under Private Information

This paper considers and compares two different legal means -- full liability and standard – to reduce and to regulate pollution at a local level accounting for private information about benefits and costs. The familiar polluter pays principle makes the polluter liable for any damage. Since the courts lack information about the true damage the pollutee can and presumably will overstate this damage. Nevertheless, voluntary arrangements bypassing the courts exist (e.g., for Coasean reasons). However, such out-of court arrangements fail to improve in many cases the inefficient allocation of pollution due to agency costs. Given these unsatisfactory consequences of the polluter pays principle even after allowing for contracts around the law, we propose a modification of standards: the pollutee is entitled that a certain standard is satisfied, yet can trade this right for financial compensations. Contracts induced by this legal rule are countervailing (the optimal mechanism switches between subsidies and payments and first best efficiency holds at both ends) and this characteristic allows such a privatized standard to track the first best quite well and (often) better than the polluter pays principle. This relative ranking under private information is the opposite of the one that holds under uncertainty (here liability dominates the standard).JEL classification: D62, D82