传统投资组合理论局限下偏度投资组合效用分析

传统投资采用的是假设投资者为风险厌恶的理论,也就是说基于期望收益相当的状况下,投资者选用的投资组合为风险较小的组合。但在现实情况中却并非如此。本文充分考虑传统投资组合理论的局限性,阐述了下偏度重大损失风险控制原理,基于信用风险迁移原理、偏度、峰度在资产组合配置中造成的影响,分析下偏度投资组合优化原理,并探讨了下偏度投资组合的特色效用。     

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     

考虑交易费用的投资组合优化模型研究

交易费用对投资组合具有影响,以下半绝对偏差作为风险度量,建立一种考虑交易费用的单位风险收益最大投资组合优化模型(一个非线性的0-1分式整数规划),可以为管理者提供组合投资和控制风险的决策参考。     

证券组合投资模型优化

以Markowitz证券组合投资理论为基础,对于几种不同证券组合投资模型分别考虑了证券组合的收益,风险,交易费等因素条件下对模型进行了优化,并对文中模型做了进一步的扩展。为投资者正确选择证券组合投资的最优策略及应用方面提供参考。     

均值-VaR分析下的资产定价模型的拓展

在均值-VaR分析框架内,首先从微观角度的单一投资期资产配置决策入手,确定无风险资产与最优风险资产组合的配置比率;并且最优风险资产组合同投资者的初始财富和风险偏好无关。将这一资产定价的微观模型应用到存在多个投资者的资本市场宏观模型当中去。发现任何投资者的预期收益率都同其承担的风险水平存在着线性相关关系。     

基于VaR和两基金分离的投资组合模型

本文使用VaR来度量投资组合的市场风险,构造了一个在可接受期末财富约束条件下,使VaR达到最小的投资组合模型,同时,发现该模型发生了两基金分离现象,因此存在多风险资产情形下的投资组合模型可以退化成为单风险资产情形下的投资组合模型。最后,本文使用简化的单风险模型对我国上海股票市场进行了实证分析,探讨投资者如何在股票和银行借贷中进行最优资产分配。     

VaR RAROC与投资组合问题探讨

以VaR为风险度量工具、以RAROC作为目标函数的投资决策模型。利用资产回报分布的偏度和峰度 ,对VaR进行调整 ,使它可以应用于非正态分布时的资产组合风险价值估计 ,而不增加计算的复杂性 ;同时又对RARAOC作了修正 ,使之克服了RAROC的缺点。应用此模型 ,使投资组合经理在受到内外部施加VaR限额约束时 ,在上级以RAROC作为投资业绩评估工具的情形下 ,可以有效地实现资产组合的优化配置。     

CreditMetrics模型在债券组合信用风险评估中的应用

信用风险是贷款和债券投资面临的主要风险,而CreditMetrics模型以其擅长计量非交易性资产的信用风险而著称,因此本文采用CreditMetrics模型来评估债券投资组合的信用风险,以期为投资者和风险管理者做出参考.     

基于CVaR的投资组合优化模型研究

风险价值(VaR)是近年来国际金融机构所倡导的测度和控制金融风险的国际主流技术,但是它在投资组合损益服从非正态分布的情形时,不满足一致性风险度量,出现尾部损失测量的非充分性。为了使具有一致性的条件风险值度量(CVaR)克服VaR的不足,构建基于CVaR约束的投资组合优化模型,该模型虑及了投资组合资产的交易成本、交易限制、资金约束和投资者的风险承受度,为制定合理的最优投资组合提供了一种新的思路。     

带投资限制的均值-半绝对偏差投资组合模型构建

本文提出了符合实际投资限制的均值-半绝对偏差投资组合模型,以投资手数作为决策变量,综合考虑不允许卖空、交易费用和最小交易单位等实际约束。通过引入正负偏差变量将模型转化为一般的线性规划问题,从而简化了模型的计算。实证结果表明,该模型合理有效,能为投资者提供决策依据。     

The impact of skewness in the hedging decision

The impact of skewness in the hedger's objective function is tested using a model of hedging derived from a third‐order Taylor Series approximation of expected utility. To determine the effect of price skewness upon hedging and speculation, analytical results are derived using an example of cotton storage. Findings suggest that when forward risk premiums and price skewness in the spot asset have opposite signs, speculation increases relative to the mean‐variance model. When the signs are identical, speculation will decrease, contradicting findings of mean‐variance models. © 2006 Wiley Periodicals, Inc. Jrl Fut Mark 26:503–520, 2006     

The economic significance of conditional skewness in index option markets

This study examines whether conditional skewness forecasts of the underlying asset returns can be used to trade profitably in the index options market. The results indicate that a more general skewness‐based option‐pricing model can generate better trading performance for strip and strap trades. The results show that conditional skewness model forecasts, when combined with forward‐looking option implied volatilities, can significantly improve the performance of skewness‐based trades but trading costs considerably weaken the profitability of index option strategies. © 2009 Wiley Periodicals, Inc. Jrl Fut Mark 30:378–406, 2010     

基于社会资本的产业集群交易治理研究——交易域、交易频率及交易对象视角的分析

文章研究了社会资本对于产业集群内部企业间交易的治理机制,从交易域、交易频率、交易对象这三个维度,对匿名市场现货交易进行扩展,建立了基于社会资本的交易治理模型,分析了产业集群内企业进行交易时的主要特点：交易嵌入社会网络、交易频率高、主要与集群内部交易对象进行交易。依据这三个特点,将上述模型进行综合,得出适用于产业集群内部企业间交易的社会资本治理机制模型,并分析了该模型的适用条件。研究结果显示由于社会资本的存在,使得产业集群内部交易得到了有效治理,这种有效治理的水平受到产业集群规模和信息畅通水平的约束,当产业集群规模不大、存在通畅的信息沟通渠道、交易者存在实施集体惩罚的动力时,社会资本能够成为产业集群内部企业间交易的有效治理机制,但是这种机制并不适用于集群内部企业与外部企业间的交易治理。     

SKEWNESS‐AWARE ASSET ALLOCATION: A NEW THEORETICAL FRAMEWORK AND EMPIRICAL EVIDENCE

This paper presents a new measure of skewness, skewness‐aware deviation, that can be linked to prospective satisficing risk measures and tail risk measures such as Value‐at‐Risk. We show that this measure of skewness arises naturally also when one thinks of maximizing the certainty equivalent for an investor with a negative exponential utility function, thus bringing together the mean‐risk, expected utility, and prospective satisficing measures frameworks for an important class of investor preferences. We generalize the idea of variance and covariance in the new skewness‐aware asset pricing and allocation framework. We show via computational experiments that the proposed approach results in improved and intuitively appealing asset allocation when returns follow real‐world or simulated skewed distributions. We also suggest a skewness‐aware equivalent of the classical Capital Asset Pricing Model beta, and study its consistency with the observed behavior of the stocks traded at the NYSE between 1963 and 2006.     

Market Timing With Moving Averages

I present evidence that a moving average (MA) trading strategy has a greater average return and skewness as well as a lower variance compared to buying and holding the underlying asset using monthly returns of value‐weighted US decile portfolios sorted by market size, book‐to‐market, and momentum, and seven international markets as well as 18,000 individual US stocks. The MA strategy generates risk‐adjusted returns of 3–7% per year after transaction costs. The performance of the MA strategy is driven largely by the volatility of stock returns and resembles the payoffs of an at‐the‐money protective put on the underlying buy‐and‐hold return. Conditional factor models with macroeconomic variables, especially the default premium, can explain some of the abnormal returns. Standard market timing tests reveal ample evidence regarding the timing ability of the MA strategy.     

逆周期资本账户管制对宏观经济稳定与社会福利改善的作用

资本管制能否有效抵御外部冲击实现宏观经济稳定存在争论,本文通过构造开放经济的DSGE模型研究投资限制和逆周期金融交易税等资本管制工具对于实现宏观经济稳定和改善社会福利的作用。通过比较不同政策安排下主要宏观经济变量的波动性和脉冲响应函数可以发现,采用逆周期金融交易税作为资本管制工具在抵御外部冲击、维持宏观经济稳定方面具有比较优势。设置投资限制的资本管制促进了货币政策的独立性,可以使货币政策专注管理国内的经济增长和通货膨胀问题。通过不同政策安排下的福利分析可知,增加投资国外资产的限制对社会福利的增进起到负面作用,增加逆周期金融交易税的资本管制却可以减轻由投资限制导致的资源配置扭曲,从而放松投资国外资产的限制从根本上提高社会福利。所以,在资本管制工具的选择上,采取逆周期金融交易税可能比采用投资限制更优。随着资本账户开放的基本条件不断成熟,用金融交易税取代投资限制更符合浮动汇率制和自由兑换的资本账户的需求。     

诺斯悖论破解、交易管制放松博弈与中国农产品流通体制转轨

从交易管制放松的理论视角分析农产品流通体制市场化转轨的内在机理与制度逻辑,文章构建一个以破解“诺斯悖论”为出发点的理论框架。在此基础上推导的动态博弈模型证明,若农产品交易管制收益的增长率不能超过成本的增长率,则国家实施农产品交易管制的努力程度将下降。农产品产量的增多增加了全面实施交易管制所需要的信息与监督费用,从而导致国家最终无法维持现存的农产品交易管制制度,不得不放松对农产品交易的管制。因此,农产品交易管制放松是国家解决“诺斯悖论”的理性选择。1978-2012年间中国农产品流通体制市场化改革的面板数据与上述理论模型基本上是一致的。     

资本资产定价模型的扩展及其在保险中的应用

传统的资本资产定价模型是在一系列过于严格化、理想化的条件下建立起来的。针对现实资本市场情况,通过对资本资产定价模型的应用条件的部分修改,如增加保险公司存在违约风险、交易费用和税收的条件,并且讨论交易费用分别为固定值和保费的函数时的情形以及税收分为固定值和变量的情形,对保费定价问题进行模型扩展。理论推导结果显示,在存在违约风险情况下,保险公司所收保费应该更低;承保费用越少,所需保费就越少;存在税负条件下的公平保费与税收水平有关。     

A secure,real-time stock market protocol

Stock markets constitute the largest electronic commerce market in the world. The tremendous growth in trading volume and the need for fast and accurate transaction execution has made the stock market one of the most technology friendly markets. The fastest growing stock exchange, NASDAQ, is a wholly electronic stock exchange with all transactions conducted over computer networks. However, the transaction model used by NASDAQ and other electronic stock markets still borrows heavily from the older traditional models used by non-electronic stock exchanges. Two important requirements of modern day stock market transactions are: (a) customer's ability to place sophisticated transaction orders to buy/sell stock, and (b) customer's ability to detect transaction delays. Modern electronic stock exchanges lack both the ability to place newer, more sophisticated transaction orders and the ability to detect delays in transaction execution. In this paper, we propose a protocol for stock market transaction that can model a new sophisticated model for transaction orders while continuing to support traditional transaction orders. The protocol is augmented with a mechanism to detect delays in transaction execution. It is further shown that the protocol proposed is secure, atomic, anonymous, private, and incurs low overhead costs. This revised version was published online in June 2006 with corrections to the Cover Date.     

Option pricing under extended normal distribution

This article proposes a closed pricing formula for European options when the return of the underlying asset follows extended normal distribution, that is, any different degrees of skewness and kurtosis relative to the normal distribution induced by the Black‐Scholes model. The moment restriction is suggested, so that the pricing model under any arbitrary distribution for an underlying asset must satisfy the arbitrage‐free condition. Numerical experiments and comparison of empirical performance of the proposed model with the Black‐Scholes, ad hoc Black‐Scholes, and Gram‐Charlier distribution models are carried out. In particular, an estimation of implied parameters such as standard deviation, skewness, and kurtosis of the return on the underlying asset from the market prices of the KOSPI 200 index options is made, and in‐sample and out‐of‐sample tests are performed. These results not only support the previous finding that the actual density of the underlying asset shows skewness to the left and high peaks, but also demonstrate that the present model has good explanatory power for option prices. © 2005 Wiley Periodicals, Inc. Jrl Fut Mark 25:845–871, 2005