Efficient markets and Bayes’ rule

Summary. A series of financial anomalies motivated the development of new theories that modify the rational expectations ideal. Two possibilities have been systematically explored. The literature on behavioral finance relaxes the assumption that agents form beliefs according to the laws of probability and assume, instead, that simpler heuristic rules are used. Another stream of the literature assumes that agents process information according to Bayes rule, but do not posses sufficient information to know the true data generating process. In this paper, Bayesian and Behavioral agents coexist and trade in a standard dynamic asset pricing model. A long-standing conjecture is demonstrated. It is shown that, under suitable assumptions, Bayesian agents drive Behavioral, non-Bayesian agents out of the market. Hence, asset prices are eventually determined under the Bayesian paradigm.Received: 3 June 2004, Revised: 17 September 2004, JEL Classification Numbers: D83.Preliminary versions have circulated under the titles Markets Favor Bayesian Models and Market Selection of Empirical Models under Limited Information. I thank Larry Blume, David Easley, Larry Epstein, Armando Gomes, Bruce Hansen, Lars Hansen, Richard Kihlstrom, Grace Koo, George Mailath, Werner Ploberger, Andrew Postlewaite and Shakeeb Khan for useful comments. I also thank participants at the NBER GE meetings, Evolutionary Finance conference in Zurich, Latin American Meetings of the Econometric Society, Stanford Institute for Theoretical Economics, the Instituto de Matematica Pura e Aplicada, the theory seminar at Brown, Chicago, Harvard-MIT, Minnesota, Penn and Wisconsin. I gratefully acknowledge the financial support from the National Science Foundation Grant SES 0109650.     

Unilateral production restrictions in a dynamic duopoly

This paper examines a dynamic game of exploitation of a productive asset by a duopoly. A closed-loop Nash equilibrium of the game is constructed and used to analyze the effects of a unilateral production restriction. Surprisingly, such unilateral action may result in a decrease of the long-run asset's stock. We also exhibit production restrictions that can result simultaneously in an increase of the asset's stock and the long-run profits of the firm that is being imposed the production restriction. Moreover, a unilateral decrease of the production of one firm can induce its rival to also decrease its production.     

The impact of product diversification strategy on the corporate performance of large Spanish firms

We analyze the impact of product diversification on performance. This topic has been discussed in the literature, and there is no consensus so far as to the significance or the direction of the impact. Performance is measured using Tobin's q for a sample of 103 large, non-financial Spanish firms (1992–1995). Diversification is measured by means of a categorical variable, as suggested by Varadarajan. The principal results indicate that the firms with intermediate levels of product diversification have the highest performance, while the firms with low and high levels of diversification show significantly lower performance, which performance is not significantly different between them.     

The impact of environmental regulation on productivity in German industries

The objective of this paper is to adjust a traditional total factor productivity (TFP) measure for the direct effect of environmental regulation on material and capital input. For this purpose we consider the fact that part of material input and pollution abatement capital have not been used to increase output but to cover the cost of using the environment as a factor of production. Therefore TFP growth rates are lower if part of the material input is allocated to abatement activities instead of producing output. We propose to treat compliance with environmental regulation as an unproductive input linked to the use of productive material input. Our aim is to answer and discuss two questions: How to measure the effect of environmental regulation on TFP, and does the effect matter. We examine data from 1975–1991 for ten pollution intensive German industries.We would like to thank Cornelia Oßwald for valuable research assistance. We are especially grateful to two anonymous referees for many helpful comments.     

General equilibrium models of monopolistic competition: A new approach

We analyze a class of ‘large group’ Chamberlinian monopolistic competition models by applying different concepts of functional separability to the same set of first-order conditions for utility maximization. We show that multiplicatively quasi-separable (MQS) functions yield ‘constant relative risk aversion’ (CRRA), and, therefore ‘constant elasticity of substitution’ (CES), functions, whereas additively quasi-separable (AQS) functions yield ‘constant absolute risk aversion’ (CARA) functions. We then show that the CARA specification sheds new light on: (i) pro-competitive effects, i.e., profit-maximizing prices are decreasing in the mass of competing firms; and (ii) a competitive limit, i.e., profit-maximizing prices converge to marginal costs when the mass of competing firms becomes arbitrarily large.     

Antidumping duties, undertakings, and foreign direct investment in the EU

We study the effects of EU antidumping policy when foreign firms can ‘jump’ antidumping duties through foreign direct investment (FDI) in the EU. We show that duty jumping or duty pre-empting FDI occurs if the EU administration has broader objectives than protecting EU industry's profitability and if cost advantages of foreign firms are transferable abroad. The (expectation of) price undertakings reduces the incentives to engage in FDI and may even discourage FDI as long as products are not too differentiated. The results are consistent with recent empirical findings on antidumping jumping FDI.     

Capital markets integration, growth and income distribution

The paper considers a two-country model of overlapping generation heterogenous economies with intergenerational transfers carried out in the form of bequest and investment in human capital. We examine in competitive equilibrium the transitory and long-run effects of capital markets integration. First, we explore how the regime of public education affects the dynamics of the integrated economy. Second, we study the effects of capital markets integration, in equilibrium, on the intragenerational income distribution in both the host and investing country.     

黄龙洞旅游开发对洞内生态环境和人的影响研究

通过对黄龙洞年内不同季节定点测定，同时与对旅游影响还不大的龙王洞对比测定，作者发现黄龙滑滑内空气CO2浓度的明显变化主要受客流量的影响。旅游旺季和黄金周客流量急剧增长带来的洞内空气CO2浓度大幅度增长，有利于岩溶作用，但洞内黑暗、高湿、低温的生态环境，对洞内工作人员身体健康有害。洞穴内岩溶景观的变化，主要受漫长的自然岩溶过程的影响，与洞内开发旅游活动的关系不大，但与洞顶山地植被保护状况有密切关系。     

Endogenous lifetime and economic growth

Endogenous mortality is introduced in a two-period overlapping generations model: probability of surviving from the first period to the next depends upon health capital that is augmented through public investment. High mortality societies do not grow fast since shorter lifespans discourage savings; development traps are possible. Productivity differences across nations result in persistent differences in capital-output ratios and relatively larger gaps in income and mortality. High mortality also reduces returns on education, where risks are undiversifiable. When human capital drives economic growth, countries differing in health capital do not converge to similar living standards, ‘threshold effects’ may also result.