Beta and firm age

We document a robust pattern of beta declining over the age of a firm. We find that changes in systematic risk via firm characteristics and life-cycle stages are insufficient to explain this pattern. Moreover, standard proxies for the quantity and quality of information also explain this pattern only partially. To fully explain this pattern we rely on the increasingly important role of familiarity in financial decision making: familiarity is a determinant of beta and firm age is a proxy for the degree of familiarity that investors feel toward individual stocks. To illustrate the implication of our findings, we document that when we control for firm age there is support for the CAPM and its use as an input for the cost of equity capital calculation.     

The structure of information release and the factor structure of returns

We model how firms releasing information on different dates causes the CAPM to fail, requiring an additional factor based on the information structure to price assets. We exemplify this mechanism’s empirical relevance using quarterly earnings announcements, which cluster across months along size and book-to-market. Seventy percent of the alpha reduction from including SMB and HML occurs in the four main earnings announcement months. The information structure factor accounts for all of SMB and HML’s seasonal alpha reduction and one third of their overall alpha reduction. Controlling for size and book-to-market, exposures to SMB and HML vary with firms’ earnings announcement month.     

Sentiment-scaled CAPM and market mispricing

This study explores the conditional version of the capital asset pricing model on sentiment to provide a behavioural intuition behind the value premium and market mispricing. We find betas (β) and the market risk premium to vary over time across different sentiment indices and portfolios. More importantly, the state β derived from this sentiment-scaled model provides a behavioural explanation of the value premium and a set of anomalies driven by mispricing. Different from the static β–return relation that gives a flat security market line, we document upward security market lines when plotting portfolio returns against their state βs and portfolios with higher state βs earn higher returns.     

The Role of U.S. Market on International Risk‐Return Tradeoff Relations

We study the intertemporal risk‐return tradeoff relations based on returns from 18 international markets. We find striking new empirical evidence that the inclusion of U.S. market returns significantly changes the estimated risk‐return tradeoff relations in international markets from mostly negative to predominantly positive. Our results are consistent with the lead‐lag effect between U.S. and international markets in the sense of Rapach, Strauss and Zhou.     

Aggregate volatility expectations and threshold CAPM

We propose a volatility-based capital asset pricing model (V-CAPM) in which asset betas change discretely with respect to changes in investors’ expectations regarding near-term aggregate volatility. Using a novel measure to proxy uncertainty about expected changes in aggregate volatility, i.e. monthly range of the VIX index (RVIX), we find that portfolio betas change significantly when uncertainty about aggregate volatility expectations is beyond a certain threshold level. Due to changes in their market betas, small and value stocks are perceived as riskier than their big and growth counterparts in bad times, when uncertainty about aggregate volatility expectations is high. The proposed model yields a positive and significant market risk premium during periods when investors do not expect significant uncertainty in near-term aggregate volatility. Our findings support a volatility-based time-varying risk explanation.     

基于小波神经网络的高阶CAPM实证研究

本文在传统CAPM的基础上,引入了一个高阶的CAPM。借助小波神经网络在非线性函数逼近方面的优势,使用上海证券交易所股票数据分别对二阶至四阶CAPM进行了实证分析。最终的研究结果表明:就上海股市而言,12只大盘股组合已经能够有效分散非系统风险,而12只小盘股不能充分化解非系统风险,存在所谓的规模效应;训练后的网络预测显示,高阶CAPM无论是在预测精度还是预测稳定性上都要明显优于传统的CAPM,在一个非系统风险得到充分分散的证券组合中,加入三阶矩的CAPM已经能够比较准确地把握风险资产的市场定价。     

CAPM对我国封闭式基金定价的实证检验

本文以上证封闭式基金为样本,选取2007年12至2010年11月的月度数据,采用单指数模型、BJS两步法和横截面检验实证分析了我国基金市场对CAPM的适用性。CAPM并不适用于我国基金市场,原因在于基金市场的不成熟以及投资主体投资理念的非理性。同时CAPM条件过于苛刻,在对资本市场进行检验时应谨慎对待。     

贝塔系数是风险的正确度量吗

在经典的投资组合理论中 ,假设所有资产的报酬率服从对数正态分布 ,因而只需要用收益的方差来度量风险就足够了 ,忽略了偏度的影响。资产收益的分布往往不是对称的 ,偏度是客观存在的 ,而且投资者具有正偏度的爱好。所以必须用方差和偏度来共同度量投资的风险 ,在这种情况下 ,贝塔系数不再是风险的正确度量 ,采用有效的修正方法 ,可以用来对资产进行正确的定价     

资本资产定价模型在中国股市的拟合程度分析

资本资产定价模型(CapitalAssetsPricingModel)是一个均衡模型的例子。在这个模型中,资产价格依赖于外部数据,投资者的体验和禀性,所以CAPM是一个相对定价模型。本文将讨论CAPM模型在中国资本市场的实证研究。由于股票市场具有规模大,数据公开等特点,我们研究CAPM模型在中国股票二级市场的实证问题。利用相关的假设检验,我们得出中国的股票市场是不满足CAPM理论(表达式)的。     

上市公司壳资源价值的实证分析

壳资源是当前中国资本市场的热点。我们考察了2001,3,1-2002/7/30的26只在上海证券交易所交易的ST股票,利用CAPM模型,分析ST股票与市场综合收益,得出ST股票的超额回报,从而反映控制上市公司或是企业控制上市公司的大股东们为了保持壳资源而注入上市企业的优良资产的价值。