有限理性下我国投资者消费与投资的选择

跨期效用最大化是经济和金融学研究范式之一,在完全理性框架下资产定价的理论取得了突破性进展,但对现实的解释还远远谈不上完美,比如"股权溢价之谜"和"消费平滑之谜"。本文在有限理性的前提下,认为消费和财富是有替代效应的,提出了和前人完全不同的效用函数,以此来阐述消费、投资和资产收益率之间的关系,该模型通过实证检验能较好地解释现实情况。     

投资者关注对金融异象的解释

本文对近年来金融理论文献中涉及的投资者关注进行综述，总结了投资者关注对资产组合集中化，传染，资产溢价和波动率之谜以及羊群效应的解释。     

我国股市异质期望对收益率影响研究

本文对我国股市中异质期望水平对股价的影响进行分析。在传统序贯交易(EKOP)模型的基础上,引入衡量投资者"看涨"、"看跌"、"看平"的参数,并定义股票的交易活跃度ρ,提出投资者预期的序贯交易模型。选取了2010年1月到2012年6月间29支股票的面板数据,并在此基础上构建异质期望的代理指标。通过面板回归分析,得出结论:投资者的异质期望水平对股票收益率产生反向的影响。投资者对某一支股票的意见分歧程度越大,其收益率越低;看法越一致,则收益率越高。并且,这种反向影响在不同的市场状况下,差异更加显著,而对于不同的股票则差别不大。     

春节文化、一月价值溢价效应与投资者非理性投资

本文以1995年1月至2010年12月间的沪深两市所有A股股票作为研究样本,采用基于广义误差分布的广义自回归条件异方差模型(GED-GARCH)对我国股票市场一月效应进行验证,结果显示我国股票市场存在显著的"一月效应"。接着,本文利用Fama-MacBeth时间序列横截面回归法验证了我国存在"一月价值溢价效应"。最后,本文研究发现春节文化可以作为解释"一月价值溢价效应"的依据。个人投资者在春节前获得大笔年终奖金后,偏好于投资高风险的股票,导致了该效应的产生。     

证券市场上股票溢价度量的影响因素探析

我国证券市场快速发展的同时,背后隐藏着巨大的风险,需要对证券市场进行正确的定位估值,分析股票溢价度量的居民消费结构差异与证券市场收益率两大影响因素,从而深层次的反映我国居民消费、投资等经济行为,可以正确理解股票溢价水平,指导投资者的行为,促进证券市场的健康可持续发展。     

Fama-French三因素模型的实证研究——以华夏大盘基金为例

在资本资产定价模型(CAPM)对资产收益率变动缺乏解释力的背景下,法玛(Fama)和弗伦奇(French)于1993年提出了著名的三因素资产定价模型,从风险收益角度出色地解释了股票超额收益率现象。本文以华夏大盘基金及其数据为例,运用Eviews软件对其进行三因素模型的实证研究,检验三因素模型在华夏大盘基金上的适用性。     

多因素资产定价模型的实证研究

以上海股市417家A股股票为样本,以2000年2月18日至2001年6月8日的周收益率为样本数据,研究股票组合收益与各种因素之间的关系,建立9个单因素模型和6个四因素模型。结果发现:6种风险度量指标对股票组合收益率的解释能力十分微弱,而平均流通市值的自然对数和平均短期(1年)历史收益率对股票组合收益率的解释能力达到76.2％。因此,在上海A股市场,CAPM失去了有效性,资产定价可以由多因素模型决定。     

我国上市银行股票超额收益率影响因素的实证分析

本文主要利用CAPM模型对我国A股市场上的金融机构进行实证检验,选取了16家上市银行的股票数据进行实证分析。结果表明,CAPM模型并不是完全失效,市场的风险溢价对于股票收益有着显著的解释能力,但同时还发现,模型拟合并不是很好,说明存在遗漏的变量,并以此对模型进行了修正,加入了规模因子和账面市值比因子。修正后的模型比原有的单因素CAPM模型来说,拟合程度有所提高,说明在我国银行业确实存在着规模效应和账面市值比效应影响着股票的超额收益率。     

股票挂钩型结构性银行理财产品收益分析

银行理财产品是近年来金融市场上新兴的投资品种之一,其中的股票挂钩型结构性银行理财产品具有收益不确定,不可赎回等特点,其收益计算方法尚不被投资者所熟悉。本文运用资本资产定价模型(CAPM),提出了股票挂钩型结构性银行理财产品的预期收益率计算方法。     

基于四因子定价模型的美国股市收益率研究

本文在Fama-French四因子模型基础上,运用Fama-French-修正GARCH模型对次贷危机影响下复苏的美国股市进行分析研究。研究发现:首先,该模型能更好地拟合美国股市的收益率,而且还能消除ARCH效应;其次,每个模型的均值方程与条件方差方程中结构突变点不同,表明不同类型的股票组合在不同时点需要添加不同的虚拟变量来对其收益率进行解释;第三,每个模型中的条件方差方程中均不存在"杠杆效应",表明2009年后股市中未出现重大的不利消息致使股市下跌,但通过研究发现滞后的股票溢价对条件方差有一定的解释力。     

Estimation Uncertainty and the Equity Premium*

This paper studies a dynamic equilibrium model of asset prices in a partially observable exchange economy. It shows that the precautionary savings motive in response to estimation uncertainty can dominate the risk aversion effect, resulting in the reduction of the equity premium over short horizons. This exacerbates the equity premium puzzle. Over longer holding horizons, however, estimation uncertainty does induce higher risk premiums on equity over risk‐free coupon bonds of matching maturities, as long‐term bond yields are lowered due to the precautionary savings effect.     

A GENERAL EQUILIBRIUM MODEL OF A MULTIFIRM MORAL‐HAZARD ECONOMY WITH FINANCIAL MARKETS

We present a general equilibrium model of a moral‐hazard economy with many firms and financial markets, where stocks and bonds are traded. Contrary to the principal‐agent literature, we argue that optimal contracting in an infinite economy is not about a tradeoff between risk sharing and incentives, but it is all about incentives. Even when the economy is finite, optimal contracts do not depend on principals’ risk aversion, but on market prices of risks. We also show that optimal contracting does not require relative performance evaluation, that the second best risk‐free interest rate is lower than that of the first best, and that the second‐best equity premium can be higher or lower than that of the first best. Moral hazard can contribute to the resolution of the risk‐free rate puzzle. Its potential to explain the equity premium puzzle is examined.     

MONOTONICITY PROPERTIES OF OPTIMAL INVESTMENT STRATEGIES FOR LOG-BROWNIAN ASSET PRICES

Consider the geometric Brownian motion market model and an investor who strives to maximize expected utility from terminal wealth. If the investor's relative risk aversion is an increasing function of wealth, the main result in this paper proves that the optimal demand in terms of the total wealth invested in a given risky portfolio at any date is decreasing in absolute value with wealth. The proof depends on the functional form of the Brunn–Minkowski inequality due to Prékopa.     

Matching the BRIC equity premium: A structural approach

The equity risk premium (ERP) in BRIC markets is, on average, significantly higher than that in the US market. This paper employs an endowment economy with recursive preferences and long-run risk to explain the ERP generated by a portfolio of BRIC equity indices. The combination of recursive preferences and long-run risk partially explains the BRIC ERP. It turns out that there is a puzzle with respect to BRIC data as well. This holds even if we account for high levels of aversion to consumption and utility risk and for the empirically observed autoregressive structure of US consumption and BRIC dividend growth.     

OPTIMAL CONSUMPTION AND PORTFOLIO DECISIONS WITH PARTIALLY OBSERVED REAL PRICES

We consider optimal consumption and portfolio investment problems of an investor who is interested in maximizing his utilities from consumption and terminal wealth subject to a random inflation in the consumption basket price over time. We consider two cases: (i) when the investor observes the basket price and (ii) when he receives only noisy observations on the basket price. We derive the optimal policies and show that a modified Mutual Fund Theorem consisting of three funds holds in both cases. The compositions of the funds in the two cases are the same, but in general the investor's allocations of his wealth into these funds will differ. However, in the particular case when the investor has constant relative risk-aversion (CRRA) utility, his optimal investment allocations into these funds are also the same in both cases.     

EXPLICIT SOLUTIONS OF CONSUMPTION-INVESTMENT PROBLEMS IN FINANCIAL MARKETS WITH REGIME SWITCHING

We consider a consumption and investment problem where the market presents different regimes. An investor taking decisions continuously in time selects a consumption–investment policy to maximize his expected total discounted utility of consumption. The market coefficients and the investor's utility of consumption are dependent on the regime of the financial market, which is modeled by an observable finite-state continuous-time Markov chain. We obtain explicit optimal consumption and investment policies for specific HARA utility functions. We show that the optimal policy depends on the regime. We also make an economic analysis of the solutions, and show that for every investor the optimal proportion to allocate in the risky asset is greater in a "bull market" than in a "bear market." This behavior is not affected by the investor's risk preferences. On the other hand, the optimal consumption to wealth ratio depends not only on the regime, but also on the investor's risk tolerance: high risk-averse investors will consume relatively more in a "bull market" than in a "bear market," and the opposite is true for low risk-averse investors.     

Security Markets versus Bank Finance: Legal Enforcement and Investors' Protection

When minority investors’ rights are poorly protected, the ability of firms to raise equity capital is impaired, leading to less finance for new ventures. Fewer firms will be financed with outside equity, resulting in a low market capitalization relative to GNP. External funding requires easily enforceable claims such as debt or requires long‐term relationships with institutions. Provision of funding shifts from risk capital to debt, and to a predominance of intermediated over market finance. We report supporting evidence for a few countries. To measure investor protection, we use a price measure, the premium on voting stock, related to the control premium. In countries where the voting premium is large, corporate financing is dominated by bank lending and equity markets are much smaller.     

ARROW–DEBREU EQUILIBRIA FOR RANK‐DEPENDENT UTILITIES

We provide conditions on a one‐period‐two‐date pure exchange economy with rank‐dependent utility agents under which Arrow–Debreu equilibria exist. When such an equilibrium exists, we show that the state‐price density is a weighted marginal rate of intertemporal substitution of a representative agent, where the weight depends on the differential of the probability weighting function. Based on the result, we find that asset prices depend upon agents' subjective beliefs regarding overall consumption growth, and we offer a direction for possible resolution of the equity premium puzzle.     

GENERAL EQUILIBRIUM WITH CONSTANT RELATIVE RISK AVERSION AND VASICEK INTEREST RATES1

We consider a pure exchange economy consisting of a single risky asset whose dividend drift rate is modeled as an Omstein-Uhlenbeck process, and a representative agent with power-utility who, in equilibrium, consumes the dividend paid by the risky asset. Endogenously determined interest rates are found to be of the Vasicek (1977) type the mean and variance of the equilibrium stock price are stochastic and have mean-reverting components A closed-form solution for a standard call option is determined for the case of log-utility. Equilibrium values have interesting implications for the equity premium puzzle observed by Mehra and Prescott (1985)     

Risk and Return in the 20th and 21st Centuries

The single most important contemporary issue in finance is the equity risk premium. This drives future equity returns, and is the key determinant of the cost of capital. The risk premium – the expected reward for bearing the risk of investing in equities, rather than in low-risk investments such as bills or bonds – is usually estimated from historical data. This article starts by summarising new evidence on historical returns in twelve major world markets from the authors' recent book, 'The Millennium Book: A Century of Investment Returns'. The authors show that the historical equity risk premium has been lower than previously believed, and argue that the future risk premium is likely to be lower still. They discuss what this implies for the cost of capital, stock market values, and companies' target rates of return. They suggest that many companies are seeking too high a rate of return and thus run the risk of under-investing.