动态均值-方差资产组合的有效性:时变风险容忍度视角

尽管均值-方差模型在静态资产组合优化过程中得到广泛运用并证明是有效的,但在动态情景下,均值-方差模型运用于动态资产组合优化过程中的有效性问题引起人们的质疑：一是常风险规避系数的设定不符合事实;二是投资者偏好设定不符合动态情景下的主流效用函数族。鉴于此,本文假设投资者风险容忍度是资产组合投资期与投资者期望收益率的函数,研究动态均值-方差资产组合的有效性问题。基于均值-方差分析框架构建时变风险容忍度下的动态资产组合模型;运用伊藤定理和拉格朗日乘子法获得最优资产组合封闭解;基于二次效用偏好下的动态资产组合,从资产组合策略、夏普率、确定性等价收益率和有效前沿等视角验证动态均值-方差资产组合策略和业绩,并予以实证。结果表明：动态均值-方差资产组合不但具有同等业绩而且体现了其灵活性和风险对冲价值;尽管动态均值-方差资产组合表现出高杠杆性,但其确定性等价收益率较高,且随投资期的增加呈现倒U型趋势;动态均值-方差资产组合的投资期效应显著,强于投资者期望收益率。研究指出,时变风险容忍度下的动态均值-方差资产组合管理和优化策略有效,但在短投资期（低于12个月）和（或）低期望收益率下并不适用。研究不但拓展了均值-方差模型在动态情境下的应用,而且体现了投资者源于心理和（或）其财富变化的投资行为调整。     

均值-方差模型具有一般不确定性下的最优资产组合选择

引入以记忆系数和无差异系数表征的随机变量测度均值-方差模型的一般不确定性特征,反映投资者的模型信任程度,研究均值-方差模型具有一般不确定性下的最优资产组合选择问题。基于资本市场线理论,构建最优资产组合选择是模型信任程度和基于均值-方差模型的传统资产组合选择的线性函数;基于记忆系数和无差异系数的不同组合,运用基于事例推理的方法求解二次效用投资者的最优模型信任程度,获得均值-方差模型具有一般不确定性下的最优资产组合,并以上证综指1997年1月-2014年8月的月度收益数据形成两个研究样本予以实证比较研究。结果表明,较大风险规避投资者,在较大记忆系数和较小无差异系数下,其模型信任程度调整较快、资产组合调整幅度大,表现出可获得性和代表性行为偏差,通常采取积极资产组合策略;反之,其模型信任程度调整渐进、资产组合调整幅度小,表现出锚定性和保守性行为偏差,通常采取消极资产组合策略;模型一般不确定性对最优资产组合选择的影响强于股票市场记忆性的影响。研究体现了投资者的有限理性,将传统的资产组合选择问题延伸至行为金融学领域。     

耦合风险视角下基于GARCH-Copula模型的基金组合风险研究

在资本市场不断多样化的投资方式中, 投资组合以其相对稳定的风险与收益而得到广泛应用, 其中基金组合凭借在收益一定的情况下的低风险成为投资者关注的热门品种.传统的投资组合研究大多只考虑市场风险的影响, 忽略了信用风险的耦合效应, 从而往往导致对组合总体风险的低估.首先借助于GARCH模型获得边缘分布, 然后选择Copula函数刻画各基金之间的相关结构, 建立联合分布模型, 进而采用Monte Carlo方法模拟生成基金组合中各基金的收益率序列, 最后根据损失函数计算基金组合的风险价值.实证结果表明, 市场风险大的基金组合其信用风险不一定大, 并且基金组合能有效分散基金风险.同时, 耦合风险视角下基金组合的CVaR值大于市场风险视角下的CVaR值, 耦合风险能更好地衡量基金组合的风险.另外, Student t-Copula模型较之其它模型能更好地刻画耦合风险的联合相依结构.     

Association of DEA super-efficiency estimates with financial ratios: Investigating the case for Chinese banks

The great majority of applications of the popular frontier technique data envelopment analysis (DEA) do not test for the association of efficiency estimates with key performance indicators used by industry observers. Nevertheless, identifying efficiency estimates’ associations with commonly accepted financial measures of performance could guide benchmarking activities, pricing decisions, and regulatory monitoring. Thus, the current paper investigates to what extent bank DEA super-efficiency estimates are associated with key financial ratios. A low correlation may present an opportunity to address inefficiencies that were not obvious in financial ratio analysis, thus enabling an update of inferences drawn from ratios. Regressing ratios on efficiency estimates may also help predict financial ratios. Where an input–output specification is comprised of key financial ratios, DEA can also be used to objectively identify benchmarks for ratio analysis based on actual observed data collected from peers. Nine super-efficiency DEA formulations across two profitability models are systematically tested. The slacks-based measure of DEA with a parsimonious profitability efficiency model emerges as the most significant combination explaining the variation in the two industry ratios, post-tax profit/average total assets and return on average equity.     

Technology-based total factor productivity and benchmarking: New proposals and an application

The present study fills a gap between the benchmarking literature and multi-output based efficiency and productivity studies by proposing a benchmarking framework to analyze total factor productivity (TFP). Different specifications of the Hicks–Moorsteen TFP index are tailored for specific benchmarking perspectives: (1) static, (2) fixed base and unit, and (3) dynamic TFP change. These approaches assume fixed units and/or base technologies as benchmarks. In contrast to most technology-based productivity indices, the standard Hicks–Moorsteen index always leads to feasible results. Through these specifications, managers can assess different facets of the firm's strategic choices in comparison with firm-specific relevant benchmarks and thus have a broad background for decision making. An empirical application for the Spanish banking industry between 1998 and 2006 illustrates the managerial implications of the proposed framework.     

基于MIDAS分位数回归的条件偏度组合投资决策

条件偏度是金融市场典型特征之一，忽略条件偏度的组合投资决策往往难以有效地分散金融风险。为此，本文构建了包含条件偏度的组合投资模型，并给出其建模方法。首先，运用MIDAS-QR模型，改善条件偏度测度效果；其次，基于CRRA效用函数，将组合投资权重设计为条件偏度和特征变量的线性组合，建立组合投资模型并给出求解方案；最后，从沪深300指数中选取10支代表性成分股进行实证研究，从收益、风险和Sharpe比率等方面，将包含条件偏度的组合投资模型与等权方案、均值-方差模型等进行比较，分析条件偏度在组合投资中的作用。实证结果表明：MIDAS-QR是测度条件偏度的有效方法，其测度结果受异常值影响小，表现稳定；条件偏度对组合投资决策具有显著影响，包含条件偏度的组合投资模型能够有效地降低投资风险、带来更高的风险调整收益。     

基于UPM-LPM的增强指数投资策略

增强指数投资策略的理念是基于部分成份股构建指数跟踪组合,以期在跟踪指数趋势的同时,获取超出指数平均收益的超额收益。本文将指数收益率作为目标收益,拓展经典下偏矩（Lower Partial Moment,LPM）的概念,使其适应于增强指数投资策略建模,同时给出上偏矩（Upper Partial Moment,UPM）的定义,进而构建基于UPM-LPM之比的增强指数模型。为解决模型的求解复杂性和高维投资组合的"维数灾难"问题,本文运用非参数核估计方法直接得到跟踪组合的密度函数,进而得到跟踪组合的LPM和UPM的解析表达式,避免对组合中各资产之间的高维联合分布进行估计,大幅度降低了估计的维度,克服"维数灾难"问题。而且LPM和UPM的核估计量是组合头寸的光滑函数,具有任意阶导数,便于优化问题求解。最后,本文运用沪深股票市场上五个常用指数及其成份股数据,检验模型在实际金融市场中的表现,结果表明：本文提出的增强指数模型能够战胜指数,同时实现跟踪指数趋势并获取稳健超额收益的目标。     

Adjexpectile风险测度的性质、优化及资产配置的应用

金融风险的度量和识别是风险管理的重要内容,常用的风险度量工具是标准差、VaR、ES,但存在很多缺陷,expectile的提出弥补了这些不足,在理论界得到广泛的讨论和应用。本文扩展了expectile进行资产配置,提出Adjexpectile的概念,并讨论和分析了Adjexpectile的一致性风险度量、随机占优性、凸性,与标准差、VaR、shortfall的关系,风险贡献及风险分解的性质。通过对六个资产指数：上证国债指数、上证企业债指数、上证180指数、深圳100指数、深成长40p指数和黄金现货指数的复合周收益率数据进行组合优化配置,发现Adjexpectile在非对称性收益数据、组合前沿、风险分散方面具有一定的优越性。     

个体投资者情绪与股票价格行为的互动关系研究

本文运用情感分析技术，在情感倾向点互信息（SO-PMI）算法的基础上，引入"拉普拉斯修正"和"情绪分类阈值"，提出了一种改进的个体投资者情绪度量的SO-LNPMI算法；基于上证指数股吧的31万条论坛信息，运用格兰杰因果检验方法研究了个体投资者情绪与市场收益率和成交量的互动关系。研究表明：（1）与经典的SO-PMI算法相比，本文提出的SO-LNPMI算法的情感识别精度更高；（2）积极情绪是股票收益率的格兰杰原因，消极情绪对其影响不显著；（3）投资者情绪与成交量存在双向的格兰杰因果关系；（4）当投资者处于积极状态时，会热衷于使用表情符号表达情绪。本文的研究为投资者情绪度量提供了一种新的有效算法，有助于投资者更好的利用网络论坛信息进行投资决策。     

时变损失厌恶下基于动态CVaR的ETF基金最优资产配置策略研究

首先对静态线性损失厌恶下的最优资产配置策略模型及其性质进行了分析,构建了基于TGARCH-EVT-POT-GPD的动态市场风险测度方法,提出了时变损失厌恶条件下基于动态条件风险约束的ETF基金最优资产配置策略模型,并基于遗传算法进行了求解。实证研究发现：当参考收益率及CVaR置信水平固定时,随着损失厌恶系数的增大,投资者采用大幅调整资产权重的方式来获得盈利的行为将逐渐减少;当参考收益率及损失厌恶系数固定且CVaR置信水平变化条件下,置信水平越高,损失厌恶投资者更偏好风险较低的资产,其对于投资风险的估计将更加敏感,投资策略更为保守;损失厌恶系数较高置信水平固定时,随着参考收益率的增加,单项资产的CVaR逐渐减小;在置信水平较高时,随着损失厌恶系数的增加,即使参考收益率增加,但投资组合的超额损失平均水平降低。     

How do Greek banking institutions react after significant events?—A DEA approach

The efficiency of Greek commercial banks is considered through the period 1995–2003 using the data envelopment analysis technique. Two approaches are used to measure efficiency: one using financial ratios as outputs only and the other viewing banks as credit generation and transaction institutions. The empirical results are used to examine the reaction of banking institutions after significant events such as M&As, privatizations and the crisis of the Athens Stock Exchange in 1999. In most cases performance deteriorates for the next 1 to 2 years, while increases thereafter, forming specific patterns of efficiency. In the last part we introduce an index to measure the management's efficiency through a process of change. The results suggest that the Greek banking sector operated efficiently on average during the destabilization periods. The contribution of the article is that it comprises the first study which examines empirically the performance behavior of banking institutions within the scope of change management theory.     

基于非对称主动风险测度的增强型指数追踪模型及应用

本文以下方追踪误差测度非对称主动风险，构建了可以折衷超额收益和下方追踪误差的增强型指数追踪模型，给出了求解模型的广义最小角度回归（generalized least angle regression，简称GLARS）算法，并基于上证50进行了实证。GLARS算法可以给出超额收益在合理区间变化时，使得下方追踪误差最小的组合系数解路径，刻画投资组合的"超额收益—下方追踪误差"有效前沿。将模型应用于中国证券市场上证50指数，与基于"超额收益—追踪误差"的增强型指数追踪模型相比，得到如下实证结论：控制组合股票支数，本文组合的超额收益、单位风险收益更高，在承担相同风险的情况下，得到了更高的平均收益补偿；正下方离差中位数、最大回撤更小，右偏程度更高，表现出"守住下限，放开上限"的特质。本文组合在稀疏性要求下，样本外可以获得高于基准指数的累积收益，对机构和个人投资者具有参考价值，丰富了现有指数追踪研究。     

基于复杂网络的投资组合优化研究

本文基于复杂网络的局部聚类系数改进了传统的全局最小方差投资组合模型。首先通过股票对数收益率的相关系数矩阵构造股票关联网络,然后计算股票关联网络的局部聚类系数,最后通过全局最小方差模型确定最佳投资组合。将改进后的模型应用于A股市场,经过夏普比率、信息比率和欧米茄比率的对比分析得出改进后的投资组合模型在样本外的表现优于传统的全局最小方差投资组合模型。     

安全投资转移视角下的跨行业投资组合模型及实证

投资者根据市场状态变化和板块轮动效应进行安全投资转移,使得资金在行业间流动,导致风险溢出。本文首次从投资者安全投资转移行为的角度对行业间风险溢出进行研究,采用大规模股票与小规模股票的订单流差异量化安全投资转移。利用状态依赖下的敏感性VaR模型（SDSVaR）衡量行业间风险溢出效应的方向和大小,进一步考虑板块轮动效应,构建跨行业投资组合模型,分析行业间风险溢出和板块轮动效应对资产配置的影响。研究发现：状态依赖下的安全投资转移显著影响行业间联动性和风险溢出;考虑行业间风险溢出的资产配置模型能够分散非系统性风险的同时降低截面维度系统性风险,提高投资者的收益,有效地规避极端风险,可以为投资者的风险管理和投资决策提供有价值的参考。     

养老金统筹账户与个人账户最优组合策略研究

本文使用投资组合理论对养老金统筹账户与个人账户的最优组合策略进行研究。为此,我们首先分析了确定性条件下的账户选择问题,然后,在随机假设下对不同账户的收益进行精算建模,在此基础上构建了养老金账户最优组合模型,最后,对上述模型进行了数值求解。研究表明：（1）统筹账户与个人账户的收益负相关,二者的组合能够形成一个有效的风险对冲机制;（2）混合制的有效边界在现收现付制和累积制的上方,因此,从风险-收益的角度讲,混合制优于单一养老金制度;（3）与最优账户组合相比,现行统筹账户的占比偏高,个人账户占比偏低。本文的政策含义在于,适当的降低现行统筹账户的占比,提高个人账户的占比能够降低养老金账户的风险水平,增加账户的收益。     

Two-stage evaluation of bank branch efficiency using data envelopment analysis

There are two key motivations for this paper: (1) the need to respond to the often observed rejections of efficiency studies’ results by management as they claim that a single-perspective evaluation cannot fully reflect the operating units’ multi-function nature; and (2) a detailed bank branch performance assessment that is acceptable to both line managers and senior executives is still needed. In this context, a two-stage Data Envelopment Analysis approach is developed for simultaneously benchmarking the performance of operating units along different dimensions (for line managers) and a modified Slacks-Based Measure model is applied for the first time to aggregate the obtained efficiency scores from stage one and generate a composite performance index for each unit. This approach is illustrated by using the data from a major Canadian bank with 816 branches operating across the nation. Three important branch performance dimensions are evaluated: Production, Profitability, and Intermediation. This approach improves the reality of the performance assessment method and enables branch managers to clearly identify the strengths and weaknesses in their operations. Branch scale efficiency and the impacts of geographic location and market size on branch performance are also investigated. This multi-dimensional performance evaluation approach may improve management acceptance of the practical applications of DEA in real businesses.     

基于项目网络支配和扩散关系的研发项目组合选择

项目组合包含多项目且项目间存在相互作用和依赖关系,针对传统项目组合评价方法忽略了各项目间依赖关系的不足,本文采用复杂网络理论和PageRank算法,提出一种新的项目优先级排序方法（PPRM）。首先,本文建立研发项目多属性评价准则,分析了项目间的支配关系以及技术和经验在项目间的扩散关系。然后,以项目为节点、以支配和扩散关系为边,分别构建了项目支配和扩散网络,进一步,采用设计结构矩阵（DSM）和K-shell方法建立了基于支配网络的项目影响力模型,并建立了考虑项目之间多次扩散传播的综合扩散概率模型。综合项目节点影响力和扩散关系,本文构建了基于PageRank算法的研发项目优先级排序模型。最后,以某研发项目组合选择为例,验证了本文所建立的模型和算法可有效分析项目组合中的排序问题。     

A note on the random yield from the perspective of the supply chain

Keren [The single-period inventory problem: extension to random yield from the perspective of the supply chain. Omega 2009;37:801-10] considers a supply chain in which the distributor faces a known demand and orders from the producer subject to a random production yield, and shows that the distributor may find it optimal to order more than what is needed due to supply uncertainty under a uniform distribution. However, Keren (2009) does not address the questions whether it is always optimal for the distributor to order more, or when to order more. In this note, we point out that ordering more is not always an optimal strategy and specify the condition under which this strategy becomes optimal. We also examine the profit losses of the supply chain members resulting from the random yield supply, which is another question not considered in Keren (2009). The producer is found to possibly benefit from this production yield uncertainty, although the performances of the distributor and of the entire supply chain are always undermined. Our results are obtained under a more generalized yield distribution, and can thus be applied to wider industrial domains.     

Non-radial profit performance: An application to Taiwanese banks

This research modifies the directional Russell measure (DRM) of Fukuyama and Weber (2009) [1] to decompose the Nerlovian profit efficiency in Chambers et al. (1998) [2] so as to obtain a generalized measure that completely excludes technical inefficiency from allocative inefficiency. Based on such a decomposition, we further develop a new slack-based and profit-oriented productivity indicator, combining the Nerlovian profit measure with the conventional Luenberger productivity indicator (LPI), in order to provide a full picture of the sources of productivity change. Productivity change, based on the profit boundary, is decomposed into four components: the change in technical efficiency; the change in allocative efficiency; the shift of technology; and the price effect from outputs and inputs. This decomposition provides a more complete picture of the sources of productivity change. The above indicator is used herein to measure the productivity change of Taiwanese banks in terms of profit.     

Perceived Value of the Mass‐Customized Product and Mass Customization Experience for Individual Consumers

The operations management literature on mass customization mainly focuses on the questions of whether and how manufacturers can efficiently deliver customization. Researchers have analyzed the trade‐offs between customization and dimensions of operational performance such as delivery times, quality, and costs. However, we argue that providing efficient customization is not sufficient per se to assess the value of mass customization. From this perspective, this paper focuses on complementary mechanisms for creating value: the benefits perceived by individual consumers. Two global components of perceived value within the context of mass customization are identified: mass‐customized product, with three dimensions, and mass customization experience, with two dimensions. The Consumer‐Perceived Value Tool (CPVT) is proposed to empirically measure the five perceived benefits related to the mass‐customized product and to the codesign process from the consumer viewpoint. The psychometric properties of the CPVT are assessed using three samples. The implications of this approach are discussed, along with directions for further research.