Market crashes,speculation and learning in financial markets

A natural conjecture is that if agents’ beliefs are almost correct then equilibrium prices should be close to rational expectations prices. Sandroni (J Econ Theory 82:1–18, 1998) gives a counterexample in an economy with sunspots and complete markets. We extend Sandroni’s result by showing that the conjecture is generically true for economies with complete markets. We consider a standard General Equilibrium model with large but finite horizon and complete markets. We show that, for almost every such economy, if conditional beliefs eventually become correct along a path of events then equilibrium prices of assets traded along this path converge to rational expectations equilibria in the sup-norm. Moreover, we establish that, generically, there exist along any such path local diffeomorphisms between individual beliefs and equilibrium prices. I would like to thank C. Ewerhart and A. Kirman for their comments, as well as the seminar participants at the University of Minho, the General Equilibrium Workshop 2005 in Zurich, and the 15th Asian General Equilibrium Conference 2007 in Singapore. An anonymous referee also provided very valuable comments.     

Market clearing, utility functions, and securities prices

Summary. We prove the existence of equilibrium in a continuous-time finance model; our results include the case of dynamically incomplete markets as well as dynamically complete markets. In addition, we derive explicitly the stochastic process describing securities prices. The price process depends on the risk-aversion characteristics of the utility function, as well as on the presence of additional sources of wealth (including endowments and other securities). With a single stock, zero endowment in the terminal period, and Constant Relative Risk Aversion (CRRA) utility, the price process is geometric Brownian motion; in essentially any other situation, the price process is not a geometric Brownian motion.JEL Classification Numbers: D52.This paper is part of my Dissertation (UC Berkeley). I am very grateful to my advisor Professor Robert M. Anderson. I also would like to thank Steve Evans, Roger Purves, Jacob Sagi, Chris Shannon and the participants of the 2002 NBER General Equilibrium Conference at the University of Minnesota (Minneapolis) for very helpful discussions and comments. This work was supported by Grant SES-9710424 from the National Science Foundation.     

Pure numbers effects, market power, and tacit collusion in posted offer markets

This paper studies the effects of seller concentration and static market power on tacit collusion in extensively repeated laboratory posted-offer markets. Contrary to the implications of some earlier research, we find that tacit collusion does not become pervasive with extensive repetition. In a ‘strong no-power’ design persistently competitive outcomes are observed in markets with three or four sellers. Even duopolies are frequently competitive in this design. Unilateral market power raises prices, as predicted. However, static Nash predictions fail to organize outcomes across power treatments, because tacit collusion moves inversely with concentration. Excess capacity appears to explain observed tacit collusion levels.     

Aggregation of heterogenous beliefs,asset pricing,and risk sharing in complete financial markets

Given a competitive equilibrium in complete asset markets, we propose a method that aggregates heterogeneous individual beliefs into a single “market probability,” which, if commonly shared by investors, generates the same marginal valuation of assets by the market as well as by each individual investor. As a result of the aggregation process, the market portfolio may have to be scalarly adjusted, upward or downward, a reflection of an aggregation bias due to the diversity of beliefs. From a dual viewpoint, the standard construction of an expected utility-maximizing aggregate investor designed to represent the economy in equilibrium, is shown to be also valid in the case of heterogeneous beliefs, modulo the above scalar adjustment of the market portfolio, thereby generating an Adjusted version of the Consumption based Capital Asset Pricing Model (ACCAPM). We analyze how the allocation of aggregate and individual risks relates to deviations of individual beliefs from the aggregate market probability. Finally, we identify the channels through which the distribution of beliefs and other microeconomic characteristics (incomes, attitudes toward risk) across investors impact the pricing of risky assets an may contribute to explaining the equity premium puzzle.     

The long run,market power and retail pricing

The paper examines the existence of market power in the respective pork and poultry (white meat) meat markets in Austria by means of the Johansen cointegration technique. The existence of market power in pork retail pricing is revealed. Poultry retail pricing is, however, found to be competitive. The result for pork is attributed to tradition and to the high pre-EU border protection rates. The paper also revealed the versatility of the Johansen cointegration technique as a tool capable of analysing both competitive and imperfect market situations. The paper recommends meat policy to be product specific rather than holistic.First version received: March 2000/Final version received: May 2003The research on which this article is based began in 1995 at the Federal Institute of Agricultural Economics, Vienna, with the support of the Austrian Federal Ministry of Agriculture and Forestry. An earlier version of the paper was presented at the 264^th NFJ Seminar, Alnarp, Sweden, 1996. The author is grateful to Karl M. Ortner for the data and to Robert M. Kunst, Karl M. Ortner, Martin Wagner and seminar participants for useful comments on earlier drafts.     

Market concentration and competition in OECD mobile telecommunications markets

This study analyses the progress of market concentration in OECD member states’ mobile telecommunications markets and evaluates the relationship between market concentration and performance. Using annual panel data from 24 OECD member states for the 1998–2011 period, the study estimates regression equations for market concentration, mobile prices and profits. The empirical results indicate that the more concentrated the mobile market, the higher the prices and profits, providing support for the market power hypothesis. If this hypothesis holds, then market concentration can be a useful indicator of market performance. On the other hand, the applicability of the hypothesis is unclear for the second half of the sample period. The results provide evidence that regulatory policies influence the structure and performance of mobile markets.     

金融资产定价理论的历史回顾与展望

金融资产定价理论是金融学的核心问题，华尔街的两次“革命”都源自于对资产定价理论的研讨。通过对金融资产定价理论的历史文献回顾，可以把资产定价理论大致分为三个阶段：萌芽阶段、发展阶段和繁荣阶段。其中，萌芽阶段在20世纪50年代以前的时间段，发展阶段在20世纪50年代到70年代，繁荣阶段则在20世纪80年代以后到目前的时间段。最后对金融资产定价理论做出展望，指出现代数学方法的运用仍是资产定价理论向前发展的动力。     

Living with ambiguity: prices and survival when investors have heterogeneous preferences for ambiguity

This paper investigates asset prices and the long run wealth of investors in an asset market populated by investors who have heterogeneous preferences over risk and ambiguity. In a dynamic setting I characterize conditions under which investors who are averse to ambiguity will have an effect on long run asset prices. If ambiguity averse investors always believe that the true distribution could be wrong in many possible directions then a necessary condition for their survival is that the market exhibit no aggregate risk, a condition not met by many asset pricing models of interest. However, unlike investors with irrational beliefs, there do exist markets in which ambiguity averse investors survive. I have greatly benefitted from conversations with David Easley, Karl Shell, Ani Guerdjikova, Val Lambson, Kristian Rydqvist, Liyan Yang, Josh Teitelbaum and Jayant Ganguli as well as seminar participants at Cornell University and the Midwest Economic Theory Meetings. I am grateful to the Solomon Fund for Decision Research at Cornell University for support.     

The revenue potential of a financial transaction tax for US financial markets

This paper estimates the revenue potential of a financial transaction tax (FTT) for US financial markets. We focus on analyzing the revenue potential of the Inclusive Prosperity Act that was introduced in the US House of Representatives in 2012 and the US Senate in 2015. The tax rates stipulated in this Act include 0.5% (50 basis points (bps)) for all stock transactions, 0.1% (10 bps) for all bond transactions and 0.005% (0.5 bps) on the notional value of all derivative trades. We examine three sets of evidence to generate potential revenue estimates: 1) the levels of transaction costs in US financial markets over time and within the range of financial market segments; 2) the extent of trading elasticities under various trading conditions; and 3) the current level of trading activity in US financial markets. Based on this evidence, we conclude that a US FTT operating at the tax rates stated above would generate about $220 billion per year, equal to about 1.2% of the current US GDP.     

金融市场发展与金融风险防范研究

随着防范和化解金融风险问题研究的深入,揭示和探讨金融风险的深层原因及根本性防范化解措施非常重要。本文分析了金融市场效率、信息不对称引发金融风险的两个深层原因及治理策略,并认为资产证券化是防范和化解金融风险的重要举措     

Asymmetric information and survival in financial markets

Summary. In the evolutionary setting for a financial market developed by Blume and Easley (1992), we consider an infinitely repeated version of a model á la Grossman and Stiglitz (1980) with asymmetrically informed traders. Informed traders observe the realisation of a payoff relevant signal before making their portfolio decisions. Uninformed traders do not have direct access to this kind of information, but can partially infer it from market prices. As a counterpart for their privileged information, informed traders pay a per period cost. As a result, information acquisition triggers a trade-off in our setting. We prove that, so long as information is costly, uninformed traders survive.JEL Classification Numbers: D50, D82, G14.I am deeply indebted to Luca Anderlini for his helpful guidance. I also benefited from discussion with Larry Blume, David Easley, Jayasri Dutta, Thorsten Hens, Hamid Sabourian, Klaus Reiner Schenk-Hoppé and Hyun Song Shin. Useful comments came from an anonymous referee and participants to seminars in Barcelona, Bielefeld, Cambridge, Manchester, Oxford, Rotterdam, Venice, Zurich, to the PhD Awards Italian tour in Rome, Naples, Padova and Milan, and to ESEM99 and EEA99 in Santiago de Compostela.     

Market power and compliance with output quotas

This paper examines the compliance behaviour of a dominant firm in an output quota market when the firm is able to exercise market power in both the quota and the output markets. Provided the firm has an initial quota endowment which is strictly positive, under some circumstances the firm may find it profitable to comply or even over-comply in its quota demand, even in the absence of enforcement. The results are compared to those found in the pollution permit literature for a firm with market dominance only in the permit market, to which some additional observations are also added concerning efficiency outcomes under non-compliance.     

不完全金融市场、海外资产结构与国际贸易

本文在动态不确定性模型分析框架下,分析了金融自由化和金融深化对一国居民消费、资产选择和福利的影响。研究表明,两国金融市场完全性的差异会导致在金融自由化的经济环境中,金融市场完全性低的国家由于有更多的预防性储蓄而出现贸易盈余,相应金融市场完全性高的国家出现贸易赤字。同时,金融市场发展的差异也深刻影响两国居民资产组合的选择,促使金融市场完全性高的国家"做多股权,做空债权",金融市场完全性低的国家"做空股权,做多债权",并导致资本从金融市场完全性低的国家主要以购买债券的形式流向金融市场完全性高的国家。     

Computing equilibria in finance economies with incomplete markets and transaction costs

Summary. Transaction costs on financial markets may have important consequences for volumes of trade, asset pricing, and welfare. This paper introduces an algorithm for the computation of equilibria in the general equilibrium model with incomplete asset markets and transaction costs. We show that economies with transaction costs can be analyzed with differentiable homotopy techniques and thus in the same framework as frictionless economies despite the existence of non-differentiabilities of agents asset demand functions and the existence of locally non-unique equilibria. We introduce an equilibrium selection concept into the computation of economic equilibria that picks out a specific equilibrium in the presence of a continuum of equilibria.Received: 2 December 2002, Revised: 15 November 2004, JEL Classification Numbers: C61, C62, C63, C68, D52, D58, G11, G12. Correspondence to: P. Jean-Jacques HeringsThis research started when Jean-Jacques Herings enjoyed the generous hospitality of the Cowles Foundation for Research in Economics at Yale University. His research has been made possible by a fellowship of the Royal Netherlands Academy of Arts and Sciences and a grant of the Netherlands Organisation for Scientific Research. We thank audiences at Stanford University, UC San Diego, and Venice for discussions on the subject. We are very grateful to an anonymous referee for very helpful comments on an earlier draft.     

Virtual integration of financial markets: a dynamic correlation analysis of the creation of the Latin American Integrated Market

This article investigates the role of virtual integration of financial markets on stock market return co-movements. In May of 2011, the Chilean, Colombian and Peruvian stock markets virtually integrated their stock exchanges and central securities depositories to form the Latin American Integrated Market (MILA). We utilize the dynamic conditional correlation model proposed by Engle (2002) to identify a statistically significant positive correlation between these markets. Moreover, we find strong evidence that the creation of the MILA increased the levels of dynamic correlation between stock returns. A higher correlation was also found during the dot-com bubble and the 2007 financial crises. Our results imply a decline in gains from international diversification by holding portfolios consisting of diverse stocks of these countries.     

The Role of Market Sentiment in Asset Allocations and Stock Returns

Abstract

The authors investigate the role of mutual fund flows in incorporating market sentiment into asset prices. They show that retail investors adjust their investments among mutual fund categories in response to changes in market sentiment. Consistent with sentiment-induced price pressure through fund flows, they further find that firms favored by mutual funds, such as large-cap, dividend payers, and firms with high institutional ownership are sensitive to market sentiment. The authors construct a pricing factor representing sentiment risk and find that the sentiment factor is significant in standard asset pricing models and robust to various sorting procedure.     

Communication in financial markets with several informed traders

This paper investigates the incentives for informed traders in financial markets to reveal their information truthfully to the public. In the model, a subset of traders receive noisy signals about the value of a risky asset. The signals are composed of a directional component (“high” vs. “low”) as well as a precision component that represents the quality of the directional component. Between trading periods, the informed agents make public announcements to the uninformed traders. With a sufficiently large number of informed traders, an equilibrium exists in which the directional components are credibly revealed, but not the precision components. Even though the informed traders retain some of their rivate information, the post-communication estimate of the asset value converges in probability to the full-information estimate as the number of informed traders increases. The paper is based on a chapter of my Ph.D. thesis at the University of Western Ontario and was circulated previously under the title “Public Communication Devices in Financial Markets.” I thank my dissertation committee Arthur Robson, Hari Govindan, and Al Slivinski for their guidance and support. I also thank Murali Agastya, Roland Benabou, Philippe Grégoire, Rick Harbaugh, Mike Peters, an anonymous referee and an associate editor, and seminar participants at various universities and conferences at which this paper was presented.     

资产定价理论与有效市场假说：简单的历史线索

全球金融危机引发了人们对于主流金融理论体系,尤其是传统资产定价理论的反思。本文对20世纪50年代以来资产定价理论的发展进行回顾与评述,以期为理解上述争议提供一个历史线索。     

Allowing communities to trade in imperfectly competitive pollution-permit markets

Citizens and organizations representing them play an increasingly important role in markets for environmental quality, but much remains to be learned about how their participation affects these markets. We analyze the effects of allowing a community of citizens to trade pollution permits in an imperfectly competitive permit market. Allowing the community to trade directly reveals its preferences, which enhances welfare. However, community participation may also exacerbate distortions due to market power, even though the community itself trades competitively. Including the community in permit distribution may exacerbate market power distortions by affecting a dominant trader’s propensity to participate in the permit market. Second, the community’s demand/supply for permits may be more inelastic than other traders and worsen distortions due to market power. We illustrate in an example that these negative effects on competition can dominate the positive effect from preference revelation through the market place.      

Theories of choice under risk: Insights from financial markets

To date, the plausibility of theories of choice under risk hinges are mainly on experimental evidence. This paper devises and implements an approach amenable of assessing the performance of three families of models (expected utility, rank-dependent expected utility, and the cumulative prospect theory) using information from financial asset markets. Our findings unequivocally support reference-point dependence, diminishing marginal sensitivity, loss aversion, and nonlinear weighting of (gain and loss) physical probabilities. The empirical observations are found to be robust to, inter alia, the parameterization of the utility and probability weighting functions, “day-of-the-week effects”, the choice of a reference point, and the introduction of possible, low-probability market crashes (peso component).