基于copula的投资组合选择模型的研究

本文首先介绍了投资组合理论与copula,然后给出基于概率P0的收益率等定义,建立基于概率P0的收益率的投资组合选择模型并给出具体解法,接着通过选取上证领先指数与深证领先指数2004年9月1日至2006年5月26日的日收盘数据进行实证分析,发现在收益率(基于概率的收益率)一定的情况下,通过投资组合可以降低风险.     

基于Copula的投资组合选择模型研究

基于概率收益率与概率风险的定义,建立基于风险与收益率的投资组合模型,为了更好拟合联合分布,在具体解法中采用Copula函数来构造多个资产收益率的联合分布。由于不要求收益率服从维纳过程,因此基于Copula的Markowitz投资组合选择模型具有更广的适用性。通过对上证领先指数与深证领先指数收盘数据实证分析发现,在收益率(基于概率ρ0的收益率)一定的情况下,通过投资组合可以降低风险。     

上证行业指数间的相关性研究及应用

投资组合中各种资产收益之间的相关性对整个投资组合的风险有着非常重要的影响。运用一种简化的GARCH模型,分析了上证行业指数间的相关性。行业指数的GARCH(1,1)模型估计结果显示,各个行业指数对数收益率的方差都明显受到各自方差的滞后值和残差滞后值的影响。通过对各行业指数残差项的分析,给出了行业指数间动态相关系数的解析表达式;并以上证能源与其余行业指数的相关性为例,给出风险投资组合的投资建议。     

证券组合投资风险控制的优化数学方法

证券组合投资是分散投资风险的有效途径。用概率统计方法,分析了基于期望收益率和方差的投资组合优化模型,并引入算例,对该模型进行了计算。结果表明,在一定的预期收益率水平下,组合投资大大降低了投资的风险。     

上证50指数及其成分股的绩效研究

投资一般分为积极投资与消极投资两大类型。前者是积极选股的,后者主要是指数化投资,它基于＂有效市场理论＂,通过复制目标指数权重构成组合投资,来获取近似于指数的收益率并分散投资风险。     

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如何挑选指数基金？
　　面对各种指数基金,投资者该怎么选择？（广东省李艳）专家：
　　指数基金(Index Fund),顾名思义就是以特定指数（如沪深300指数、标普500指数、纳斯达克100指数、日经225指数等）为标的指数,并以该指数的成份股为投资对象,通过购买该指数的全部或部分成份股构建投资组合,以追踪标的指数表现的基金产品。通常而言,指数基金以减小跟踪误差为目的,使投资组合的变动趋势与标的指数相一致,以取得与标的指数大致相同的收益率。     

理财实务咨询 | CONSULTATION

如何挑选指数基金？
　　面对各种指数基金，投资者该怎么选择？（广东省李艳）专家：
　　指数基金(Index Fund)，顾名思义就是以特定指数（如沪深300指数、标普500指数、纳斯达克100指数、日经225指数等）为标的指数，并以该指数的成份股为投资对象，通过购买该指数的全部或部分成份股构建投资组合，以追踪标的指数表现的基金产品。通常而言，指数基金以减小跟踪误差为目的，使投资组合的变动趋势与标的指数相一致，以取得与标的指数大致相同的收益率。     

基金经理更换、股票联动与股票价格

基金经理更换打破了基金共同持股投资组合中股票的关联性,降低了股票收益率相关性,进而影响了股票价格。本文基于基金共同持股和基金经理更换构建了对冲投资组合,获得0.1%的日超额收益率。基金投资组合中股票收益率相关性能够解释这种超额收益率,本文发现基金更换经理后,新基金经理重建投资组合,打破了原投资组合中股票间的关联,股票收益率相关性减弱,基金共同持股程度高的股票价格受到了更大影响。基金的被动流动性冲击不能解释本文的发现。本文的研究表明基金经理变更等基金管理行为通过股票收益率相关性对股票价格产生了重要影响。     

基于熵理论的金融市场风险测度及实证研究

目前主流的金融风险测度方法如Va R、CVa R和ES都是基于均值-方差分析框架,刻画金融风险都通过分析收益率分布,且大多将收益率分布描述成正态分布;然而,这种传统方法不能很好地拟合证券市场诸如尖峰厚尾形态的真实分布。物理学中的熵可以用来度量不确定性程度,选取熵值最大的概率分布可以更好地描述证券市场价格随机过程。将熵理论引入金融风险测度研究中,利用最大熵分布对道琼斯指数、纳斯达克指数、德国DAX指数、法国CAC指数、日经225指数、上证指数等欧、美、亚典型并具有代表性的6个证券指数近20年的日数据进行实证分析得出,这种度量方法可以更加准确刻画证券市场收益率分布以及描述金融风险特征。     

基于价值投资的Piotroski选股策略实证研究

本文通过Priotroski的基于P/B股票特征的财务指标评分选股方法对中国A股上市公司的股票2000～2012年的历史行情进行回溯实证研究,检验基于价值投资的Piotroski选股策略在中国股票市场的适用性。结果表明,Priotroski选股策略构造的股票组合盈利能力良好,远超过同期的市场指数的收益率,因而是值得推广使用的投资选股策略。     

Minimizing the lifetime ruin under borrowing and short-selling constraints

In this paper, the optimal investment strategies for minimizing the probability of lifetime ruin under borrowing and short-selling constraints are found. The investment portfolio consists of multiple risky investments and a riskless investment. The investor withdraws money from the portfolio at a constant rate proportional to the portfolio value. In order to find the results, an auxiliary market is constructed, and the techniques of stochastic optimal control are used. Via this method, we show how the application of stochastic optimal control is possible for minimizing the probability of lifetime ruin problem defined under an auxiliary market.     

Would emerging market pension funds benefit from international diversification: investigating wealth accumulations for pension participants

In recent years, investment portfolio selection is growing in importance for many emerging market pension funds, as pension reforms replace traditional pay-as-you-go systems with advanced funding systems. Various investment regulations are applied to the funded pensions, particularly in the form of portfolio limits for equities and international assets. With a bootstrap simulation approach, this paper attempts to quantify the impacts on retirement benefits of restricting international assets from the investment portfolios of emerging market pension funds. We find that, on average, over half of the pension portfolios of emerging market countries should be in international assets in order to maximize the expected utility of moderate and conservative pension fund participants. More generally, international assets can play a significant role in the investment portfolios for workers with risk aversion varying from aggressive to conservative. With few exceptions, the entire probability distribution of wealth accumulations at retirement could be shifted higher with the inclusion of international assets.     

证券投资组合损失率概率评价模型的开发与实证检验

通过建立证券投资组合损失率概率评价模型,定义损失率概率为单个资产或投资组合的损失率超过市场平均损失率的概率,用于对投资组合的风险进行评价。以某基金为例,计算得到该基金的损失率概率为39.74%,表明该基金有39.74%的概率损失率超过市场平均损失率。以证券投资组合损失率概率最小为目标函数,采用遗传算法进行求解,得出该基金投资组合损失率概率最小时的投资权重系数,最小损失率概率为36.01%,与该基金公司的投资组合相比,损失率概率降低了3.73%,实例证明该模型是降低证券投资组合风险的一种实用方法。     

Efficient fund of hedge funds construction under downside risk measures

We consider portfolio allocation in which the underlying investment instruments are hedge funds. We consider a family of utility functions involving the probability of outperforming a benchmark and expected regret relative to another benchmark. Non-normal return vectors with prescribed marginal distributions and correlation structure are modeled and simulated using the normal-to-anything method. A Monte Carlo procedure is used to obtain, and establish the quality of, a solution to the associated portfolio optimization model. Computational results are presented on a problem in which we construct a fund of 13 CSFB/Tremont hedge-fund indices.     

Moments of multivariate regime switching with application to risk-return trade-off

We use a Fourier transform to derive multivariate conditional and unconditional moments of multi-horizon returns under a regime-switching model. These moments are applied to examine the relevance of risk horizon and regimes for buy-and-hold investors. We analyze the impact of time-varying expected returns and risk (variance and covariance) on portfolio allocations' “term structure”—portfolio allocations as a function of the investment horizon. Using monthly observations on S&P composite index and 10-year Government Bond, we find that the term structure of the optimal allocations depends on market conditions measured by the probability of being in bull state. At short horizons and when this probability is low, buy-and-hold investors decrease their holdings of risky assets. We also find that the conditional optimal portfolio performs quite well at short and intermediate horizons and less at long horizons.     

Applying Portfolio Change and Conditional Performance Measures: The Case of Industry Rotation via the Dynamic Investment Model

This paper applies portfolio change and conditional performance measures to assess the performance of the dynamic investment model in various industry-rotation settings spanning the 1934–1995 period. The dynamic investment model employs the empirical probability assessment approach in raw form. In addition, it incorporates three adjustments for estimation error: James–Stein, Bayes–Stein, and CAPM-based corrections. The tests are unanimous in their conclusion that the excess returns attained by the (unadjusted) historic, the Bayes–Stein, and the James–Stein estimators are (sometimes highly) statistically significant over the 1966–1995 and 1966–1981 sub-periods. This lends support to the idea that the joint empirical probability assessment approach based on the recent past, with and without Stein-based corrections for estimation error, contains information that can be profitably exploited. The relationship of these findings to the extant literature on momentum and contrarian strategies is addressed.     

互联网金融资产的多目标投资组合研究

互联网金融的快速发展和不断创新,正在悄然改变着公众的投资理财行为。本文在分析互联网金融创新下公众流动性偏好、投资行为变化与资产选择的基础上,构建基于CRRA(常数相对风险厌恶)期末财富期望效用最大化和VaR最小化的多目标投资组合模型。同时引入多目标优化的NSGA-Ⅱ遗传算法,并选择实际数据对模型进行求解,得出最优的互联网金融资产组合。研究表明:(1)互联网金融给传统金融业带来冲击的同时,也改变了人们的流动性偏好、投资行为和资产组合选择。(2)互联网金融在一定程度上调和了金融资产“流动性、收益性和安全性”之间的矛盾,并兼顾了“三性”的相对统一。(3)模型求解结果显示,投资者对互联网金融资产的投资组合为低风险类资产60%左右、高风险类资产40%左右。     

International Portfolio Investment Flows

This article develops a model of international equity portfolio investment flows based on differences in informational endowments between foreign and domestic investors. It is shown that when domestic investors possess a cumulative information advantage over foreign investors about their domestic market, investors tend to purchase foreign assets in periods when the return on foreign assets is high and to sell when the return is low. The implications of the model are tested using data on United States (U.S.) equity portfolio flows.     

A knowledge‐based framework for incorporating investor's preference into portfolio decision‐making

This paper describes a framework for the integration of a rule‐based system capable of identifying an investor's risk preference into a quantitative portfolio model based on risk and expected return. By inferring rules consisting of an investor's objective and subjective risk preferences, the integrated methodology provides the assets suitable for the preferences. Through investment in the portfolio composed of the assets, the investor is able to obtain the following bene?ts: reduction of costs and time spent to determine target assets, and alleviation of anxiety from ‘out‐of‐favor’ assets. The framework is applied to the development of a knowledge‐based portfolio system for constructing an investor's preference‐oriented portfolio. In the procedure of the system for ?nding an optimal portfolio, the system uses an arti?cial intelligence method of a case‐based reasoning to obtain preference thresholds for an investor when the investor's past investment records are available. Experimental results show that the framework contributes signi?cantly to the construction of a better portfolio from the perspective of an investor's bene?t/cost ratio than that produced by the existing portfolio models. Copyright © 2004 John Wiley & Sons, Ltd.