“均值—方差”模型分析应用于最有效的证券组合的研究

证券及其它风险资产的投资首先需要解决的是两个核心问题：即预期收益与风险。那么如何测定组合投资的风险与收益和如何平衡这两项指标进行资产分配是市场投资者迫切需要解决的问题。文章应用马科维茨均值—方差模型进行最有效证券的研究,建立了资产优化配置的均值—方差模型。     

上证指数收益率波动研究

各国的资本市场以及大量的统计数据证明,股票价格的收益率波动并不是标准的正态分布,而是具有"尖峰厚尾"的统计特征。收益率的方差出现"时聚性",即具有异方差的特征。且股价收益率具有不对称性,即负面消息的冲击要显著大于正面利好消息的影响。基于股票收益波动率的此类特点,文章首先对上证综合指数进行描述统计分析。针对通过差分得到平稳的收益率时间序列,运用ARCH模型进行实证分析,并选择GARCH类模型中拟合效果最好的进行蒙特卡洛模拟,运用计算机仿真手段得到更加稳健的参数与分析结果。     

中国证券市场收益分形分析

股票市场收益记忆特征对于系统非线性结构的确定以及市场有效性的研究具有重要的意义。本文针对上海和深圳的周和日收益序列，采用重标级差（R／S分析）对其进行了实证研究。从统计结果来看，样本序列呈现出尖峰、胖尾等有偏特征，明显不满足正态分布的假设，表明收益序列可能具有长程相关或记忆性。进一步的研究表明分形市场假说比传统的有效市场假说更好地描述了中国证券市场的非线性特征。     

我国基于总收益形式与超额收益形式估计的证券贝塔比较分析

经过简化的基于总收益形式的指数模型被经常用来估计证券贝塔,但这个模型没有理论依据。由于我国无风险利率的方差与市场收益的方差变动比较起来非常小,短期无风险利率的实际变动对贝塔估计值影响很小,因此,从“预测”的角度看,用总收益形式的单指数模型估计贝塔值可以完全替代具有理论基础的超额收益形式的单指数模型估计的贝塔。     

基于截集的加权可能性均值-方差模型

本文以模糊数的截集为切入点,给出随机变量取值为模糊数时基于截集的加权可能性均值、加权可能性方差和加权可能性协方差的定义,研究了基于截集的加权可能性均值、加权可能性方差和加权可能性协方差的性质,给出三角模糊数的基于截集的加权可能性均值、加权可能性方差和加权可能性协方差的具体形式.并以基于截集的加权可能性均值作为证券组合投资收益率为模糊数时投资未来收益的度量,以基于截集的加权可能性方差作为证券组合投资收益率为模糊数时投资风险的度量,以基于截集的加权可能性协方差作为不同资产之间相关程度的度量,以不同的权重表示不同投资者的对投资收益的风险偏好程度,构建基于模糊数截集的加权可能性均值-方差组合投资模型,给出模型的求解方法.最后将基于截集的加权可能性均值-方差模型与传统的均值-方差模型进行了比较分析,并结合我国证券交易市场的具体实例说明该模型的应用价值.     

动量与反转效应来源的分解——风格、行业与序列相关性

文章使用Lo和MacKinlay(1990)的相对强度加权策略(WRSS)的研究方法,以A股为研究对象,从风格、行业与序列相关性三方面探讨了动量和反转效应的来源。实证结果显示:个股呈现反转效应,而风格的动量十分明显,行业具有微弱的反转效应。这种不同的主要来源是资产的序列自相关与收益横截面的方差。     

组合证券的多选少模型研究

一、问题的提出组合证券投资是分散投资风险的有效途径。H.M.Markowitz的组合证券投资决策模型奠定了现代组合证券投资理论的基础。在Markowitz理论中,风险证券的评价采用预期收益率和收益率方差（代表风险）两项指标。理性的投资行为应具有“非满足性”和“风险回避”两个特征,即在给定风险条件下寻求最大期望收益率或在一定期望收益条件下使投资风险最低,由此给出了两个等价的组合证券投资决策模型。应用Markowitz模型进行组合证券投资决策的过程是：投资者首先根据一定的原则和偏好选择一组证券作为投资对象,然后对这组已选好的投…     

股市收益率与波动性长期记忆效应的实证研究

股票市场长期记忆效应问题是近来金融实证研究的一个热点.多数的研究集中在收益率长期相关性的考察上,较少有对波动率序列的研究.然而,波动率的长期记忆性不仅会导致金融市场上的波动持久性特征,而且将对波动率的预测与衍生证券定价产生重要的影响.基于此,本文通过修正的R/S分析与ARFIMA模型对我国股市收益率及其波动性的长期相关性进行了实证研究.结果表明:中国股市具有显著的非线性特征,虽然收益率序列的自相关性较弱,但波动性序列却表现出显著的长期记忆效应.这一结论将为研究股票价格行为特征与金融经济学理论提供新的方向.     

关于证券投资风险的表述及相关模型分析

一、对马柯维茨相关理论假设前提的思考毋庸置疑,马柯维茨最初提出的分析收益风险的均值方差模型具有划时代的意义。他以方差度量风险代替非定量化的主观判断具有重要的理论突破价值。但结合实际情况加以分析,马柯维茨理论的假设前提值得进一步推敲。首先,马柯维茨理论中暗含假设。因为证券的收益率受到证券市场、所处行业以及企业自身等众多因素的影响,所以是随机变量,服从正态分布。因为对于正态分布而言,只要期望值、方差确定了,收益率分布情况也就确定了,由此马柯维茨以收益率的期望值和方差度量证券的收益和风险。从国外的研究…     

我国开放式基金市场收益率波动性研究

自从2001年首只开放式基金发行以来,我国开放式基金迅速发展,逐渐占据基金主体地位,但有关开放式基金市场收益率渡动性研究的文献并不多.一般认为,自回归问题是时间序列数据所特有,而异方差性是横截面序列数据的特点,本文通过对2003年以来我国开放式基金市场收益率序列数据进行研究,发现我国开放式基金市场收益率序列不服从正态分布,具有明显的"尖峰厚尾"特征,并且收益率的波动存在明显的集聚性.运用GARCH(1,1)模型较好的描述了这一波动特征.     

Learning,estimation, and the stability of rational expectations

The stability of the rational expectations equilibrium of a simple asset market model is studied in a situation where a group of traders learn about the relationship between the price and return on the asset using ordinary least squares estimation, and then use their estimates in predicting the return from the price. The model which they estimate is a well-specified model of the rational expectations equilibrium, but a misspecified model of the situation in which the traders are learning. It is shown that for appropriate values of a stability parameter the situation converges almost surely to the rational expectations equilibrium.     

The case against eliminating large denomination bills

When large denomination bills are preferred in illegal activities, what is the optimal policy response? We construct a dual currency model where illegal activity can be reduced by modifying the payment environment. In our model, legal (goods) traders are indifferent between small and large bills, but illegal (goods) traders face a lower transaction cost of using large bills in comparison to small bills because it is easier to conceal. We show that eliminating large bills can reduce illegal trade and its associated social cost. However, this pooling equilibrium is sub-optimal because the government can collect more seigniorage by allowing illegal traders to use large bills with a lower rate of return. When the transaction cost of using small bills for illegal traders is sufficiently large, a separating equilibrium, where legal traders use small bills and illegal traders use large bills, can maximize welfare by making an implicit transfer from the illegal traders to the legal traders.     

The Effects of Subject Pool and Design Experience on Rationality in Experimental Asset Markets

Empirical evidence suggests that prices do not always reflect fundamental values and individual behavior is often inconsistent with rational expectations theory. We report the results of fourteen experimental asset markets designed to examine whether the interactive effect of subject pool and design experience (i.e., previous experience in a market under identical conditions) tempers price bubbles and improves forecasting ability. Our main findings are: 1) price run-ups are modest and dissipate quickly when traders are knowledgeable about financial markets and have participated in a previous market under identical conditions; 2) price bubbles moderate quickly when only a subset of traders are knowledgeable and experienced; 3) the heterogeneity of expectations about price changes is smaller in markets with knowledgeable and experienced traders, even if such traders only represent a subset of the market; and 4) individual forecasts of prices are not consistent with the predictions of the rational expectations model in any market, although absolute forecast errors are smaller for subjects who are knowledgeable of financial markets and for those subjects who have participated in a previous market. In sum, our findings suggest that markets populated by at least a subset of knowledgeable and experienced traders behave rationally, even though average individual behavior can be characterized as irrational.     

Modelling the relationship between future energy intraday volatility and trading volume with wavelet

Although the energy and stock markets are both characterized by volatility and liquidity, and there has been substantial research to explore the relationship between volatility and trading volume (TV) in stock markets, few researchers have investigated this relationship in energy markets. Moreover, studies that have explored this association within energy markets did not describe its nature or impetus. To redress this oversight, we investigate this relationship using intraday data from the oil and gas markets – the most liquid energy markets in the world. In this way, the current article extends the previous studies through the use of a frequency approach to propose an original analysis of the relationship between volume and volatility. More specifically, we employ a continuous wavelet transform to identify the lead–lag phase between volatility and volume. This framework supplants usual time series modelling, as it uses a measure of coherence for different frequencies and time-scales to capture further changes and time variation in the volume–volatility relationship. Our results provide supportive evidence for the well-known positive relationship between realized volatility and TV, thereby supporting the mixture distribution hypothesis. In particular, our results show that volume causes volatility only during ‘turbulent times’, while volatility causes volume during ‘good times’. Furthermore, there is no relationship between volume and volatility in the long term, due to the absence of noise traders and liquidity traders in the long run. These findings are helpful for investors and policymakers as they contribute to better forecast the TV and price volatility during turbulent and calm periods and over several investment horizons.     

Conservative traders,natural selection and market efficiency

This paper examines the impact of conservative traders on market efficiency in an evolutionary model of a commodity futures market. This paper shows that the long-run market outcome is informationally efficient, as long as in every period there is a positive probability that entering traders are more conservative than their predecessors. Conservative traders are those who correctly predict the spot price with a positive probability, and more importantly, who in their mistakes err on the side of caution, and rarely overpredict the spot price as buyers, and underpredict the spot price as sellers. This result does not require entry of traders with better information than their predecessors.     

Spillovers from the USA to stock markets in Asia: a quantile regression approach

This article analyses return spillovers from the USA to stock markets in Asia by means of quantile regressions. Traditional studies consider spillovers as effects of the conditional means of foreign returns onto the conditional means of chronologically succeeding domestic markets’ returns. We, by contrast, study the full range of quantiles of the conditional distribution of the domestic markets’ returns. This enables us to document the detailed structure of spillovers across return quantiles. Generally, we find spillovers from the USA to Asia to be negative. Specifically, however, we reveal an asymmetric structure of spillovers with an increasing negative magnitude from lower to upper return quantiles. Theoretically, this pattern is consistent with an asymmetric overreaction of traders in Asia to news from the US market. Extensions from the baseline model further suggest the presence of contagion throughout the financial crisis of 2007–2008 as well as of calm-down effects over weekends.     

基于市场周转率的股票市场收益预测

我国许多股票交易者在交易时追求流行,偏爱交易高周转率的热门股票,偏爱在市场火热时入市。这种行为使高周转率的股票以及高周转率的市场时期可能具有超额利润。我们利用两个自回归求积移动平均法模型成功地发现中国股票市场的周转率可以预测股票收益。     

The effect of risk-taking behavior on profitability: Evidence from futures market

We explore how futures traders make a tradeoff between risk and return by examining their risk-taking in the action. By applying a novel measure to their trade-by-trade transactions to capture their tendency in risk-taking, we find a general tendency to reduce risk-taking by cutting positions when facing losses or gains, and the tendency is stronger in the case of losses. However, great variations exist among traders in the risk-taking tendency and the results for trading are opposite for profitable and unprofitable traders. For the unprofitable, more risk-taking by trading more actively leads to greater losses. This is concrete evidence for the prevailing belief in the literature that trading too much, arguably due to overconfidence, is hazardous to investor's wealth. Contrary to that belief, however, we find fresh evidence that more active trading by the profitable traders leads to greater profits, suggesting their trades are likely based on ability and skills.     

基于FIGARCH模型的中国房地产指数的实证分析

在T分布和正态分布假设下采用GARCH模型和FIGARCH模型对上证地产股指数日收益率序列进行建模分析,结果表明,上证地产股指数日收益率序列的波动具有显著的长记忆性,表明外部冲击对波动有着长期的影响。因此,采用FIGARCH模型建模的效果优于采用GARCH模型建模的效果,并且在T分布假设下拟合模型,其效果优于在正态分布假设下拟合的模型。