本文将股权分置改革本身看做是上市公司拥有的永久性美式看涨期权多头, 并 运用期权分析框架, 分析了股权分置改革时机的选择问题、流通股股东与非流通股股东的博 弈、预期与价格跳跃过程, 找到了该期权定价公司和提前执行该美式期权的最优执行边界, 消 除了在股权分置改革过程中出现的一些认识上的误区, 并对中国的股权分置改革问题提出了 一些政策性建议。

长期以来, 人们都认为期货市场具有价格发现功能, 即期货价格是未来现 货价格的无偏估计。本文分别对投资性资产和消费性资产的期货价格进行了分析, 从理论 上证明了期货价格不能作为未来现货价格的无偏预期, 并讨论了期货价格与现在现货价格 以及未来现货价格的关系, 指出了在这些问题上长期存在的理论和实证误区。

　对期货价格和现货价格关系中长期存在的理论和实证研究误区进行了分析与澄清,从理论上证明了在一般情况下期货价格不是未来现货价格的无偏预期,更不能以此作为期货市场效率的检验标准.提出期货市场的价格发现功能应界定为对同期现货价格的引领作用,认为期货市场效率包括定价效率与信息效率,只有一个定价有效的期货市场才能充分发挥其风险管理的功能. 在实证方面,提出了适合于检验期货与现货价格关系的三种检验模型,并根据上述结论分别运用协整检验、格兰杰因果检验和广义谱分析方法检验了1990 年9 月21 日至2007 年12 月20 日期间S&P500指数现货和期货市场的定价效率、价格领先滞后关系和信息效率.

本文考察流动性受限对资产定价的影响，即所谓不流动性折扣，并研究不流动性折 扣的影响因素及其时变特征，以期对股权分置改革过程中对价的确定标准是否合理提供理论 支持。我们证明了不流动性资产从根本上影响了最优组合策略，并且，我们在流动约束情形 下的随机波动模型中对代理人最优组合问题提供了初始的封闭解。本研究结果表明不流动资 产折价率受到流动约束的时间长短、不流动资产的波动率等诸多参数的显著影响，因此并不 支持股权分置改革公司的对价水平趋同现象。

长期以来理论界和实务界对于在证券市场上是否应该允许卖空存在很大的争议，争议的焦点之一就在于卖空交易是否会加大市场的波动性，甚至引发市场危机。因此本文选取了世界上37个国家和地区的证券市场作为研究对象，站在整个市场层面探讨了卖空机制对股指收益率偏度、波动性和市场崩溃概率等的影响。实证结果发现虽然放开卖空限制将导致股指收益率向负向偏离，但却不会加大市场的波动性，反而可以降低市场崩溃的概率。

The debate among various market partic-ipants on the short-selling of securities continues today. Opponents of short-selling argue that it disrupts orderly mar-kets by causing panic selling, high vola-tility, and market crashes. So this paper investigates what the impact of short sell-ing on the volatility and liquidity of Hong Kong stock market is, and the results in-dicate that short selling volumes do not Granger-cause market volatility, but volatility Granger-cause short selling volumes. Moreover Granger causality tests show that there is a double direc-tional causality relationship between short selling volumes and market liquidity.

In this paper, we pay attention to the relationship between stock index and increments of trading accounts in A, B share market and funds. We show that there exists bilateral relationship between A, B index and their trading accounts increments. However, Granger causality only exists from stock index to increments of funds accounts. Regressions show that the investors’ sentiment will be easily driven by the index in the same direction, which imply momentum strategy in a very short period. In comparison, when using weekly data, only increments of funds accounts Granger cause the stock index. These uncover the differences between fund managers and small investors while investing on stock market. We also analyse the relationship between index volatility and trading accounts volatility.

This paper examines a wide variety of popular volatility models for stock index return, including Random Walk model, Autoregressive model, Generalized Autoregressive Conditional Heteroscedasticity (GARCH) model, and extensive GARCH model, GARCH-jump model with Normal, and Student-t distribution assumption as well as nonparametric specification test of these models. We fit these models to Dhaka stock return index from November 20, 1999 to October 9, 2004. There has been empirical evidence of volatility clustering, alike to findings in previous studies. Each market contains different GARCH models, which fit well. From the estimation, we find that the volatility of the return and the jump probability were significantly higher after November 27, 2001. The model introducing GARCH jump effect with normal and Student-t distribution assumption can better fit the volatility characteristics. We find that that RW-GARCH-t, RW-AGARCH-t RW-IGARCH-t and RW-GARCH-M-t can pass the nonparametric specification test at 5% significance level. It is suggested that these four models can capture the main characteristics of Dhaka stock return index.

证券市场微观结构对资产定价的影响在近年来的金融文献中受到了越来越多的重视。大量的证券市场微观结构文献已经阐明了信息不对称与资产价格之间的重要联系，但是这种信息不对称是否是资产价格的显著决定因素到目前为止还没有一致的结论。本文首先对信息风险度量的相关文献进行了较为全面的整理和评述，然后就信息风险是否为资产价格的显著决定因素的相关文献进行综述，最后对研究现状进行了总结，并指出了未来的研究方向。

：目前我国常用的三大经典基金绩效考核模型都是以均值－方差CAPM模型为基础，而均值―方差CAPM模型中的系统性风险只考虑二阶矩风险即波动率，忽略了高阶矩风险。本文通过在传统CAPM模型中加入零成本的负协偏度投资组合和零成本的正协峰度投资组合作为高阶矩风险溢价重新解释基金风险与收益间的平衡关系,发现众多基金的投资组合中都存在负协偏度风险，基于高阶矩的考核模型优于基于传统CAPM的考核模型。