GAME THEORETIC MODELS OF MIXED OLIGOPOLY

Abstract. In this paper we review various models that have been proposed for the study of mixed oligopoly, that is markets in which private and public firm compete on equal basis using only market instruments.     

关于期权薪酬会计计量方法的思考

股票期权薪酬计量方法的选用一直以来都存在争议,采用不同的计量方法会直接影响到股票期权会计信息的真实性和透明度。本文通过对分别运用内在价值法、最小价值法和公允价值法中的B-S模型和二叉树模型对期权薪酬价值的计算分析,来说明何种计量方法能最有效地实现期权薪酬核算的目的。     

基于期权定价理论的所有者与债权人代理问题分析

所有者和债权人之间的代理关系是现代公司治理的重要要素,如何理解和处理二者之间的关系成为社会关注的核心。本文从期权角度对所有者与债权人之间的代理关系进行新的理解,并分别介绍了无风险套期保值、B-S期权定价理论模型的具体运用以及保护债权人利益的具体措施。     

用期权定价模型评估企业并购的价值

针对传统企业并购价值评估模型的局限性,本文从期权的角度阐述了企业并购的期权特性,指出企业并购实质上相当于取得了一个看涨期权;并以连续支付红利的美式期权定价理论为基础,建立了企业并购价值评估的期权定价模型。最后,通过实例论述了如何应用该模型来评估企业并购价值,对实践中企业并购价值的合理确定具有重要的指导意义。     

Tax Effects in a Model of Product Differentiation: A Note

We investigate how unit (or specific) tax and ad valorem tax affect equilibrium location choice in a model of product differentiation, which includes Hotelling (linear-city) and Vickrey-Salop (circular-city) spatial models as special cases. We find that neither tax affects equilibrium location patterns as long as each firm has the same production cost. Two taxes can yield different location patterns under cost heterogeneity among firms.     

Giffen goods and market making

Summary. This paper shows that information effects per se are not responsible for the Giffen goods anomaly affecting traders demands in multi asset noisy, rational expectations equilibrium markets. The role that information plays in traders strategies also matters. In a market with risk averse, uninformed traders, informed agents have a dual trading motive: speculation and market making. The former entails using prices to assess the effect of error terms; the latter requires employing them to disentangle noise traders demands within aggregate orders. In a correlated environment this complicates the signal extraction problem and may generate upward sloping demand curves. Assuming (i) that competitive, risk neutral market makers price the assets or that (ii) uninformed traders risk tolerance coefficient grows unboundedly, removes the market making component from informed traders demands rendering them well behaved in prices.Received: 30 April 2002, Revised: 3 December 2003, JEL Classification Numbers: G100, G120, G140.Support from the Barcelona Economics Program of CREA and the Ente per gli Studi Monetari e Finanziari Luigi Einaudi, are gratefully acknowledged. I thank Anat Admati, Jordi Caballé, Giacinta Cestone, and Xavier Vives for useful suggestions. The comments provided by the Associate Editor and an anonymous referee greatly improved the papers exposition.     

Market clearing and derivative pricing

Summary. We develop a method of assigning unique prices to derivative securities, including options, in the continuous-time finance model developed in Raimondo (2001). In contrast with the martingale method of valuing options, which cannot distinguish among infinitely many possible option pricing processes for a given underlying securities price process when markets are dynamically incomplete, our option prices are uniquely determined in equilibrium in closed form as a function of the underlying economic data.Received: 14 April 2003, Revised: 7 January 2004, JEL Classification Numbers: G13, D52.This paper is dedicated to Birgit Grodal, whose strength and character we greatly admire. We are very grateful to Darrell Duffie, Steve Evans, Botond Koszegi, Roger Purves, Jacob Sagi, Chris Shannon, Bill Zame and an anonymous refereee for very helpful discussions and comments. The work of both authors was supported by Grant SES-9710424, and Andersons work was supported by Grant SES-0214164, from the National Science Foundation.     

Pro-cyclical effect of sovereign rating changes on stock returns: a fact or factoid?

This article examines the effect of changes in sovereign credit ratings and their outlook on the stock market returns of European countries at different phases of business cycle. Using standard four-factor model, it records a significant average marginal effect of credit rating announcements on stock market returns. Both magnitude and significance of the effect vary with business cycle and across announcement types. However, we do not find evidence of pro-cyclical effect of sovereign rating and outlook changes on stock returns. Our results show that stock markets react more negatively to rating downgrades in recovery phases and more positively to rating upgrades in contractionary period. Both results are statistically significant and robust to various sensitivity tests.     

最优再保险的期权博弈分析

期权博弈理论把期权定价和博弈论结合起来分析在连续时间和不确定性下的动态多人决策问 题。本文运用这种方法首先分析了超额损失再保险的期权特性,用期权定价技术为其定价,然后构建一个 完全信息动态博弈模型分析了原保险人和再保险人的最优策略和均衡结果,给出了无套利条件下的最优超 额损失再保险。与传统精算及其它经济分析文献不同,在此框架下得到的最优再保险保费体现了市场因 素,并反映了利益冲突的保险主体之间顺序动态决策的事实。     

金融中介及关系银行——基于广东外资企业银行融资数据的研究

本文根据外资银行和国有商业银行向在中国境内的外资企业提供的外币贷款和人民币贷款的数据 ,对金融中介及关系银行进行了实证研究。我们的主要结论有两点 :第一 ,企业与银行建立起来的金融业务关系越长久 ,那么其所获得的外币贷款利率就越低。这是对金融中介理论的支持。另外 ,外资控股、第三方担保等因素 ,也具有降低外币贷款利率的效应。第二 ,人民币贷款的利率随着外资企业与更多的银行建立和保持合作关系而降低。人民币贷款主要是由我国商业银行提供。如果商业银行间的竞争仅仅是用来作为信贷定价的主要决定因素 ,而不是用来推进金融创新 ,提供高质量的金融产品和服务 ,那么这将会损害我国商业银行的获利能力并进而影响金融系统的健康发展。