On optimal investment with processes of long or negative memory

We consider the problem of utility maximization for investors with power utility functions. Building on the earlier work Larsen et al. (2016), we prove that the value of the problem is a Fréchet-differentiable function of the drift of the price process, provided that this drift lies in a suitable Banach space.We then study optimal investment problems with non-Markovian driving processes. In such models there is no hope to get a formula for the achievable maximal utility. Applying results of the first part of the paper we provide first order expansions for certain problems involving fractional Brownian motion either in the drift or in the volatility. We also point out how asymptotic results can be derived for models with strong mean reversion.     

Do investors like to diversify? A study of Markowitz preferences

We study rankings of completely and partially diversified portfolios and also of specialized assets when investors follow so-called Markowitz preferences. It turns out that diversification strategies for Markowitz investors are more complex than in the case of risk-averse and risk-inclined investors, whose investment strategies have been extensively investigated in the literature. In particular, we observe that for Markowitz investors, preferences toward risk vary depending on their sensitivities toward gains and losses. For example, it turns out that, unlike in the case of risk-averse and risk-inclined investors, Markowitz investors might prefer investing their entire wealth in just one asset. This finding helps us to better understand some financial anomalies and puzzles, such as the well known diversification puzzle, which notes that some investors tend to concentrate on investing in only a few assets instead of choosing the seemingly more attractive complete diversification.     

投资组合模型的改进研究:基于企业社会责任视角的实证分析

在尊重和借鉴前人对企业社会责任研究,尤其是在企业社会责任评价研究基础之上,本文从投资者的角度在投资组合过程中研究企业社会责任。在Markowitz(均值—方差)理论模型上添加企业社会责任的三个一级指标期望作为目标函数,由此将传统的投资组合模型扩展为五个目标函数的投资组合选择模型,而且我们根据经济学中经典的效用函数理论证明了此模型的正确性。本文引入主流的企业社会责任评价标准,并对一些典型公司进行打分量化。在此基础之上建立了以期望回报率、回报率的方差、核心利益相关者期望、蛰伏利益相关者期望和边缘利益相关者期望为目标函数的投资组合选择模型,在最小方差曲面上选取10个点构造投资组合,并以样本外的数据验证了模型的有效性。研究发现:根据此模型计算出来的部分投资组合回报率显著高于同期的市场指数。研究结果表明,这种关注企业社会责任的多目标投资组合选择模型,不仅让投资者可以直接控制企业社会责任,而且实际数据证明了此模型的优势之处,从而为关注企业社会责任的投资者提供一种投资的方法和思路。     

考虑投资者风险态度的随机模糊投资组合模型及实证

考虑投资者面临证券市场随机和模糊的双重不确定性,把证券收益率视为随机模糊变量。在前景理论下考虑投资者的风险态度,建立不同的随机模糊收益率、期望收益隶属度函数和目标权重,构建考虑投资者风险态度的随机模糊投资组合模型。采用实证方法把市场分为下降和上升两个阶段,研究不同风险态度投资者的投资组合差异及模型表现。结果表明:投资者的风险态度会影响投资组合的结构;考虑投资者风险态度的随机模糊投资组合模型,能够满足不同风险态度投资者对投资收益和风险的差异需求,且在实际投资决策中具有可行性。     

具有一般效用函数与允许卖空的资本市场中均衡价格向量的存在性与唯一性

对有有限多个其效用函数为一般凹函数的投资者参与的资本市场，在假设风险资产收益的联合分布为椭圆分布之下，通过考虑期望效用最大化问题，我们导出了使市场出清的均衡价格向量存在唯一的条件及其计算公式，并简要讨论了所给条件的经济意义，所得结果推广了有关资产市场均衡分析的某些结果。     

对中国期货机构投资者锚定启发式偏差的实证研究

本运用行为金融学的理论，通过对期货投资情绪变化和历史投资收益率进行回归分析，检验了中国期货经纪公司这类机构投资是否存在锚定启发式偏差。经过分析，得出了中国期货机构投资具有锚定启发式偏差的结论。     

复杂系统演化方程的重正化群解研究

很多复杂系统本身具有长大倾向导致微观系统会表现出向宏观发展的趋势.而对于具有多层次多要素的复杂系统来说,重正化群是一种非常好的研究方法,就是对复杂系统演化方程的重正化群解研究.给出了衰减因子、激发因子和综合因子作用下的重正化群变换解,并以中国股票市场为例计算了以演化时间和投资者开户数增长率为自变量的股票市场重正化群函数.     

从投资情绪角度看股票市场流动性——来自B股向境内居民开放的研究

我们借鉴行为方面的模型,即投资情绪的变化会影响股票市场的流动性,从而影响股票的未来收益。在卖空限制条件下市场高流动性预示市场充斥着非理性投资者。本文通过中国股市具备卖空限制和2001年2月B股向境内居民开放前后B股投资主体(投资情绪)发生变化这一自然事件,实证分析了B股市场向境内居民开放后,投资者情绪变化引起市场流动性增加,对股票预期收益的流动性溢价影响也由开放前的不显著变化为显著。     

机构调研行为的示范效应研究——基于深证“互动易”平台的实验证据

基于深交所“互动易”平台的机构调研信息和投资者问答数据,以投资者关注为聚焦点,通过剖析机构调研行为-投资者关注-股票流动性的传导路径,检验中国股票市场机构调研行为的示范效应。结论表明,机构调研行为具有强烈的示范效应,能够通过引起其他投资者的关注,促进中短期股票流动性的提高,且机构调研行为越集中,这种示范效应越强。此外,对于信息披露质量较低和机构持股比例较低的公司,机构调研行为更容易引起投资者的关注,示范效应更强。研究结论验证了机构投资者的信息优势性和行为影响力,支持了投资者的信息解读能力,为机构投资者的市场引导作用提供解释依据。     

广义Cox模型下的逐步扩大域流相关问题研究

在本文中, 我们主要讨论了广义Cox模型的信息流扩大问题. 假设在市场中有两类投资者, 第一类投资者拥有市场信息, 这里由一个维的布朗运动和一个可积随机 测度驱动; 而第二类投资者具有扩大的信息流, 这里假设是由信息流和广义Cox的模型刻画的违约信息流生成. 我们建立和刻画了广义Cox模型并且求给出它的主要性质包括生存过程和违约条件密度. 与Cox模型显著区别的是, 如果违约由广义Cox模型模型刻画, 与Cox模型平凡的结果不同的是, 鞅的分解更复杂和具有一般性.     

Convergence of Utility Indifference Prices to the Superreplication Price: the Whole Real Line Case

A discrete-time financial market model is considered with a sequence of investors whose preferences are described by concave strictly increasing functions defined on the whole real line. Under suitable conditions we prove that, whenever their absolute risk-aversion tends to infinity, the respective utility indifference prices of a given bounded contingent claim converge to the superreplication price. We also prove that there exists an accumulation point of the optimal strategies’ sequence which is a superhedging strategy.     

The Optimal Interaction between a Hedge Fund Manager and Investor

ABSTRACT

This study explores hedge funds from the perspective of investors and the motivation behind their investments. We model a typical hedge fund contract between an investor and a manager, which includes the manager’s special reward scheme, i.e., partial ownership, incentives and early closure conditions. We present a continuous stochastic control problem for the manager’s wealth on a hedge fund comprising one risky asset and one riskless bond as a basis to calculate the investors’ wealth. Then we derive partial differential equations (PDEs) for each agent and numerically obtain the unique viscosity solution for these problems. Our model shows that the manager’s incentives are very high and therefore investors are not receiving profit compared to a riskless investment. We investigate a new type of hedge fund contract where the investor has the option to deposit additional money to the fund at half maturity time. Results show that investors’ inflow increases proportionally with the expected rate of return of the risky asset, but even in low rates of return, investors inflow money to keep the fund open. Finally, comparing the contracts with and without the option, we spot that investors are sometimes better off without the option to inflow money, thus creating a negative value of the option.     

情绪对股票投资收益及后续投资决策的影响

金融学视角的研究使用市场变量代表投资者情绪,未能触及情绪本质.从心理学视角出发,使用行为金融实验方法,研究股票投资者的真实情绪对收益率及后续决策风险偏好的影响.结果发现:1)股价单边下跌时,产生适度消极情绪的个体收益最高.2)对于后续盈利情境的决策,前期产生积极情绪的个体倾向于规避风险,产生消极情绪的个体倾向于寻求风险;对于后续亏损情境的决策,个体均表现为寻求风险.3)股价单边上涨或下跌时,个体最容易出现的具体情绪分别是"倍受鼓舞"、"内疚"等.     

目标约束下的投资选择

根据 Markowitz投资组合理论和传统的期望效用理论 ,在效用函数相同的情况下 ,所有的理性投资者都将采用相同的最优投资策略 .但在现实中 ,不同的投资者往往采用不同的投资策略 ,依据传统理论只能认为他们并不都是理性投资者 .本文引入了目标约束后 ,说明了由于不同的投资者具有不同的目标约束 ,所以用传统的期望效用理论无法解释的看似非理性的行为其实却是理性的最优选择 .     

长期投资者的战略资产配置选择

在股票期望收益率服从一个均值回复过程的假设下,推导出具有幂效用函数的投资者的资产配置函数,着重分析了投资期限对投资者资产配置结果的影响,发现长期投资者比短期投资者在股票上配置更大的资产比例.虽然不同投资期限的投资者具有相同的短视配置,但是战略配置随着投资期限的增大而增大.     

Hedge fund performance appraisal using data envelopment analysis

In this paper we apply data envelopment analysis (DEA) to evaluate the performance of hedge fund classifications. The purpose of alternative investment strategies such as hedge funds is to offer absolute returns, so using passive benchmarks to measure their performance could be ineffective. With the increasing number of hedge funds available, institutional investors, pension funds, and high net worth individuals urgently need a trustworthy efficiency appraisal method. DEA can achieve this. An important benefit of the DEA measure is that benchmarks are not required, thereby alleviating the problem of using traditional benchmarks to examine non-normal distribution of hedge fund returns. We suggest that DEA be used as a complimentary technique (or method) for the selection of efficient hedge funds and funds of hedge funds for investors. Using DEA can shed light and further validate hedge fund manager selection with other methodologies.     

Jump-diffusion international asset allocation

We examine international asset allocation with jump-diffusion assets in the presence of risky deviations of exchanges rates from purchasing power parity when investors consume both traded and nontraded goods. We show that adding new jump risks to existing diffusion assets does not alter investors’ original optimal portfolios of diffusion assets, as long as diffusion-risk premia remain unchanged. We also show that hedge portfolios against purchasing power parity deviations are integral parts of optimal portfolios for investors from different countries, and they can be constructed by using foreign and domestic inflation-indexed bonds. Moreover, country-specific demand for risky assets can arise from nontraded-good-specific inflation-rate-differential risks.     

Multiple Fund Investment Situations and Related Games

This paper deals with interactive multiple fund investment situations, in which investors can invest their capital in a number of funds. The investors, however, face some restrictions. In particular, the investment opportunities of an investor depend on the behaviour of the other investors. Moreover, the individual investment returns may differ. We consider this situation from a cooperative game theory point of view. Based on different assumptions modelling the gains of joint investment, we consider three corresponding games and analyse their properties. We propose an allocation process for the maximal total investment revenues.Ruud Hendrickx acknowledges financial support from the Netherlands Organisation for Scientific Research (NWO).     

Hedging the Risk of Delayed Data in Defaultable Markets

We investigate hedging the risk of delayed data in certain defaultable securities through the local risk minimization approach. From a financial point of view, this indicates that in addition to the risk of default, investors also face incomplete accounting data. In our analysis, the delay is modelled by a random time change, and different levels of information, including the full market’s, management’s, and investors’ information, are distinguished. We obtain semi-explicit solutions for pseudo locally risk minimizing hedging strategies from the perspective of investors where the results are presented according to the solutions of partial differential equations. In obtaining the main results of this paper, we apply a filtration expansion theorem that determines the canonical decomposition of stopped special semimartingales in an enlarged filtration of investors’ information.     

Sensitivity of portfolio VaR and CVaR to portfolio return characteristics

Risk management through marginal rebalancing is important for institutional investors due to the size of their portfolios. We consider the problem of improving marginally portfolio VaR and CVaR through a marginal change in the portfolio return characteristics. We study the relative significance of standard deviation, mean, tail thickness, and skewness in a parametric setting assuming a Student’s t or a stable distribution for portfolio returns. We also carry out an empirical study with the constituents of DAX30, CAC40, and SMI. Our analysis leads to practical implications for institutional investors and regulators.