异质信念与资产定价研究综述

在传统金融理论中,投资者被假设为同质的,具有一致的理性预期,这与现实并不相符,也无法对"股权溢价之谜"等金融异象提供合理的解释.行为金融中的异质信念理论与现实更加符合,也为解释这些异象提供了理论支持.本文以异质信念的来源为线索,对投资者的异质信念与资产定价的关系进行了综述.     

投资者异质信念影响股票价值溢价吗？--基于分析师收益预测的角度

本文利用资产组合分析和包含分歧风险因子的多因素模型,分析了投资者异质信念对股票价值溢价的影响。研究结果表明：投资者异质信念对价值型股票组合和流通市值大的股票组合的价值溢价具有显著影响,且投资者异质信念程度越大,这类股票组合的价值溢价也越大。     

异质信念与中国股票市场的IPO异象 ——理论分析与中国实证

本文基于中国新股发行特征构建了IPO定价模型,模型结果表明在严监管条件下,信息不对称和非理性偏差形成的异质信念会推高IPO首日收益。本文进一步使用2005～2015年1413个IPO样本进行实证检验。研究表明,异质信念对IPO异象收益具有可靠的解释能力,基于信息不对称和非理性偏差构建的异质信念越高,IPO异象收益越大,且这种影响主要源于一级市场抑价。另外,研究还发现,异质信念越大,IPO长期表现越差。据此,本文建议新股发行改革应该重视新股信息披露,培育合格投资者,减少市场非理性投机行为。     

投资者异质信念与定向增发股价长期市场表现

近年来,基于异质信念的行为金融理论已经成为国际学术界的重要研究前沿。本文结合中国资本市场特殊制度背景,首次从投资者异质信念视角实证检验了上市公司定向增发后股价长期市场表现。研究结果表明:投资者异质信念越大,上市公司实施定向增发后公司股价长期市场表现越差;当发行对象为机构投资者时,异质信念对定向增发后股价的负向作用更加显著。此外,本文还进一步发现公司定向增发后的经营业绩变化也与投资者异质信念呈显著负相关关系。本文的研究结论丰富了投资者异质信念假说在公司股权再融资领域中的研究范畴。     

随机游走、行为金融、混沌与资产定价理论的新发展

从随机游走、行为金融到混沌,从现代资产定价理论、行为资产定价理论到异质信念资产定价理论,三种学说和三种定价理论同时存在于当今资本市场的研究中,它们分别从不同方面、不同视角解释了资产价格的波动。本文的研究理清了三种重要定价理论之间的关系:理性与有限理性,线性与非线性,价格波动的外在机制与内在机制,为人们进一步研究资产定价理论提供了清晰的脉络。     

上市公司定向增发方式选择:基于投资者异质信念视角

本文以2006-2011年在沪深两市通过定向增发实现再融资的A股上市公司为研究对象,首次在全流通背景下理论分析和实证检验了投资者异质信念对上市公司定向增发方式选择的影响。研究结果表明:对于实施定向增发的上市公司来说,投资者异质信念越大,越倾向于选择向机构投资者增发新股;投资者异质信念与定向增发规模负相关;当大股东参与定向增发时,投资者异质信念越大,大股东越有动机利用资产认购新增股份。本文的研究拓展了行为金融理论在企业融资特别是增发融资方面的研究视野。     

产品市场势力与股票市场交易量:基于异质信念的解释

基于2001年至2009年A股市场上市公司的数据,本文从异质信念的角度检验了产品市场势力与股票市场交易量之间的关系。结果发现产品市场势力的提高能显著促进个股的交易,这与Peress(2010)的研究一致。不同的是,我们发现产品市场势力提高能通过增加投资者的异质信念水平促进交易,这和本文的预期一致。另外,我们的结果还表明产品市场势力与投资者单笔的交易量显著正相关。     

随机游走、行为金融、混沌与资产定价理论的新发展

从随机游走、行为金融到混沌,从理代资产定价理论、行为资产定价理论到异质信念资产定价理论,三种学说和三种定价理论同时存在于当今资本市场的研究中,它们分别从不同方面、不同视角解释了资产价格的波动.本文的研究理清了三种重要定价理论之间的关系:理性与有限理性,线性与非线性,价格波动的外在机制与内在机制,为人们进一步研究资产定价理论提供了清晰的脉络.     

异质信念对股价波动的非对称性影响研究

本文利用上市公司的相关数据,实证研究了异质信念对我国股票市场股价波动的 影响,探讨了在不同的市场行情和企业性质下异质信念对股价波动的非对称性影响,并对融资 融券推出前后异质信念对股价波动的非对称性影响进行了研究。研究结果表明：（1）股票投 资者异质信念的差异程度越大,股价偏离其股票的内在价值就越大,进而导致股价的波动程度 更剧烈;（2）异质信念对股价波动的影响呈非对称性,在熊市行情下异质信念对股价波动的 影响要高于牛市,在国有企业背景下异质信念对股价的波动程度大于非国有企业;（3）融资 融券推出后在一定程度上可以减缓异质信念对股价波动的影响。     

投资者异质信念与中国股市收益

本文研究了投资者异质信念对于股市后期收益率的影响。从行为金融角度以卖方分析师的一致预期作为投资者异质信念的度量,并基于Fama的研究从市值,市净率,以及动量将股票分为三个组别,观测了其三个月之后的收益变化。     

完全市场中的资产定价——有限离散时间情形

研究完全市场中有限离散时间情形下的资产定价问题。首先,给出了无风险收益的概念,借助无风险收益定义了一种风险中性概率。基于这个概率,得到了资产的价格等于随机现金流与随机贴现因子乘积的期望,而且资产的价格还等于资产支付关于q的期望对无风险收益的贴现值。其次,借助无风险概率考虑了资产在多期情形下的资产定价,得出了相应的股票期权公式,尤其作为推论给出了欧式看涨期权的定价公式,并对资产价格过程的鞅性作了讨论。     

The performance of model based option trading strategies

This paper analyzes returns to trading strategies in options markets that exploit information given by a theoretical asset pricing model. We examine trading strategies in which a positive portfolio weight is assigned to assets which market prices exceed the price of a theoretical asset pricing model. We investigate portfolio rules which mimic standard mean-variance analysis is used to construct optimal model based portfolio weights. In essence, these portfolio rules allow estimation risk, as well as price risk to be approximately hedged. An empirical exercise shows that the portfolio rules give out-of-sample Sharpe ratios exceeding unity for S&P 500 options. Portfolio returns have no discernible correlation with systematic risk factors, which is troubling for traditional risk based asset pricing explanations.     

Nonlinear asset pricing in Chinese stock market: A deep learning approach

The redesign of asset pricing models failed to integrate the frequent financial phenomenon that stock markets exhibit a non-linear long- and short-term memory structure. The difficulty lies in developing a nonlinear pricing structure capable of depicting the memory influence of the pricing variable. This paper presents a Long- and Short-Term Memory Neural Network Model (LSTM) to capture the non-linear pricing structure among five elements in the Chinese stock market, including market portfolio return, market capitalisation, book-to-market ratio, earnings factor, and investment factor. The long–short-term memory structure implies that the autocorrelation function of the stock return series decays slowly and has a long-term characteristic. The LSTM model surpasses the standard Fama–French five-factor model in terms of out-of-sample goodness-of-fit and long–short strategy performance. The empirical findings indicate that the LSTM nonlinear model properly represents the nonlinear relationships between the five components.     

Is there a real estate factor premium?

In this paper, we study the variation of expected returns on five different asset portfolios in a multi-factor model. We found the presence of a real estate factor, in addition to both a stock factor and a bond factor in asset pricing. This suggests that mutual fund managers should seriously consider including real estate assets in their portfolios, since one cannot capture the real estate factor premium without having some kind of real estate exposure. Another result is that the market segmentation found in previous studies disappears in a more general model of asset pricing in which we allow for multi-factors other than the market factor to affect asset returns. This implies that real estate assets can be treated just like other assets as far as mean-variance efficient asset allocations are concerned. We also have some preliminary evidence that equity REITs and the Russell-NCREIF index are driven by the same underlying real estate factor.     

FUNCTIONAL FORMS OF THE CAPITAL ASSET PRICING MODEL UNDER DIFFERENT MARKET RISK REGIMES

This paper demonstrates that, given the assumption that asset returns are generated by the linear market model, the same functional form for the capital asset pricing model can be derived via the simpler linear programming approach for the riskaverse, risk-neutral, and risk-loving market regimes.     

A simple asset pricing model with heterogeneous agents,uninsurable labor income and limited stock market participation

In this paper we study a simple two-period asset pricing model to understand the implications of uninsurable labor income risk and/or borrowing constraints, limited stock market participation, heterogeneous labor income volatilities, and heterogeneous preferences. We appraise the performance of each of these in matching moments of asset returns to the data and show that limited stock market participation generates a significantly large equity premium. We also show that the distribution of wealth between stock market participants and non-participants plays an important role in asset pricing, and that the effect of borrowing constraints on asset returns are similar to that of limited participation. Finally, we discuss the practical implications of our investigation, providing an appraisal of ongoing changes in asset returns.     

Perfect option hedging for a large trader

Standard derivative pricing theory is based on the assumption of agents acting as price takers on the market for the underlying asset. We relax this hypothesis and study if and how a large agent whose trades move prices can replicate the payoff of a derivative security. Our analysis extends prior work of Jarrow to economies with continuous security trading. We characterize the solution to the hedge problem in terms of a nonlinear partial differential equation and provide results on existence and uniqueness of this equation. Simulations are used to compare the hedging strategies in our model to standard Black-Scholes strategies.     

动态不完全市场中不流动资产的定价

流动性对资产收益有重大影响,流动性好坏与资产能否流动是不同层面的问题,前者属于完全市场,后者属于不完全市场,但经典的金融经济学主要研究完全市场上的资产定价和最优组合策略。本文基于中国的现实制度背景,考察流动性受限对资产定价的影响,构建了动态不完全市场中不流动资产的定价模型及最优组合策略;证明了不流动性资产从根本上影响了最优组合策略,不流动资产折价率受到流动约束的时间长短、不流动资产收益的波动率等诸多参数的显著影响。     

The option CAPM and the performance of hedge funds

We evaluate the investment performance of hedge funds using an asset pricing model that is characterized by a piecewise-linear stochastic discount factor, and which we estimate using the generalized method of moments by minimizing the Hansen–Jagannathan distance. Our results show that, once non-linearities and public information are taken into account, there is only evidence of positive performance for the overall hedge fund index, equity-market neutral strategy and the global macro strategy.     

Information and capital asset pricing

Investors in a market frequently update their diverse perceptions of the values of risky assets, thus invalidating the classic capital asset pricing model's (CAPM) assumption of complete agreement among investors. To accommodate information asymmetry and belief updating, we have developed an empirically testable information-adjusted CAPM, which states that the expected excess return of a risky asset/portfolio is solely determined by the information-adjusted beta rather than the market beta. The model is then used to analyze empirical anomalies of the classic CAPM, including a flatter relation between average return and the market beta than the CAPM predicts, a non-zero Jensen's alpha, insignificant explanatory power of the market beta, and size effect.