非正定方差阵下的证券组合投资模型研究

研究了非正定方差阵下,证券组合投资模型的最优投资比例系数的计算,有效边界,冗余证券的数量以及套利机会.从而为实证分析提供了理论依据和方法.     

Arbitrage in skew Brownian motion models

Empirical skewness of asset returns can be reproduced by stochastic processes other than the Brownian motion with drift. Some authors have proposed the skew Brownian motion for pricing as well as interest rate modelling. Although the asymmetric feature of random return involved in the stock price process is driven by a parsimonious one-dimensional model, we will show how this is intrinsically incompatible with a modern theory of arbitrage in continuous time. Application to investment performance and to the Black-Scholes pricing model clearly emphasize how this process can provide some kind of arbitrage.     

基于遗传算法的多因素证券组合投资决策模型

基于 APT理论 ,在不允许卖空、并考虑交易成本的情况下 ,本文建立了多因素证券组合投资决策模型 ,然后利用遗传算法研究了模型的求解     

Correct or incorrect application of CAPM? Correct or incorrect decisions with CAPM?

This paper focuses on inconsistencies arising from the use of NPV and CAPM for capital budgeting. It shows that: (i) CAPM capital budgeting decision-making based on disequilibrium NPV is deductively inferred by the capital asset pricing model, (ii) the use of the disequilibrium NPV is widespread in finance both as a decision rule and as a valuation tool, (iii) the disequilibrium NPV does not guarantee additivity nor consistency with arbitrage pricing, so that it is unreliable for valuation, (iv) Magni’s [Magni, C.A., 2002. Investment decisions in the theory of finance: Some antinomies and inconsistencies. European Journal of Operational Research 137, 206–217; Magni, C.A., 2007a. Project valuation and investment decisions: CAPM versus arbitrage. Applied Financial Economics Letters 3 (2), 137–140] criticism of the NPV criterion refers to the disequilibrium NPV, and De Reyck’s [De Reyck, B., 2005. On investment decisions in the theory of finance: Some antinomies and inconsistencies. European of Operational Research 161, 499–504] project valuation method, on the basis of which Magni’s criticism to NPV is objected, leaves decision makers open to arbitrage losses and incorrect decisions.     

Capital budgeting,investment project valuation and financing mix: Methodological proposals

A firm using a discount rate defined at the corporate scale as a weighted average cost of capital (WACC) may have to value projects subject to a different tax rate from the one used to calculate its discount rate. Moreover, to determine the economic value of a project, the WACC and Arditti–Levy methods need to be adjusted if the firm allocates to this project a loan representing proportionally more (or less) than the fraction corresponding to the target debt ratio defined by the firm for projects in the same class of risk. We first propose a method which corresponds to the adjustment of standard WACC calculations. The formulation adopted (“generalized ATWACC method”) has the advantage of being independent of any consideration related to debt ratios. We then develop a consistent adaptation of the Arditti–Levy method (“adapted BTWACC method”), but it does not possess the simplicity of that of the generalized ATWACC method.     

基于个体公平原则的寿险产品定价模型

在无套利框架的基础上,讨论基于个体公平原则下的寿险产品定价问题,即运用倒向随机微分方程理论,将投保人和保险人置于同一系统中进行考虑:首先,根据双方的随机投资决策目标分别建立无套利寿险定价模型和动态资产份额定价模型,得出两个特殊线性倒向随机微分方程的显式解;然后,建立基于个体公平原则的寿险定价模型,从投保人和保险人双方的角度对寿险产品进行公平定价,得出了从供需双方考虑的投资回报定价公式;最后,利用所建立的模型进行案例分析,计算出基于个体公平原则的保费及保险公司的投资策略.该寿险产品定价模型不仅考虑了保险人的意愿,还同时考虑了投保人的实际情况,因此,按此定价理念开发出的保险产品,不仅可以提高产品研发的成功率,而且使得研发出的新产品更能在竞争激烈的保险市场中站稳脚步.     

基于不确定理论的风险中性测度及其在欧式期权定价中的应用

首先运用不确定理论推导了相应的不确定风险中性测度,修正了已有文献中涨跌期权不满足无套利原则的问题.然后将所得的风险中性测度用于欧式看涨和看跌期权的定价,并验证了涨跌期权价格之间的平价关系.最后研究了一类利差期权的定价问题,结合定义的风险中性测度给出了期权的定价公式.所推导的不确定风险中性测度与经典的无套利原则相吻合,而且考虑到了问题描述过程中存在的不精确性,弥补了单纯依赖随机理论的不足,可广泛地应用于金融衍生品的定价过程,为投资分析提供一定的理论依据.     

创新驱动模式下战略性新兴产业政府补贴策略分析

针对政府补贴难以激励战略性新兴产业形成创新驱动力的问题,以新能源汽车产业为例,构建了一个旨在促进企业技术研发的政府创新补贴策略分析模型。假设产业呈现明显的创新驱动特征,模型分别针对政府理性决策与有限理性决策的情况,对政府创新补贴及企业创新投入策略进行了博弈均衡分析,并讨论了技术创新环境的改善对最优策略及局中人收益的影响。结果表明,在创新驱动模式下,企业最优创新投入比例对政府补贴水平不敏感,且过高的补贴可能挤出企业创新投入,容易形成企业套利空间。此外,改善技术创新环境对强化企业市场主体地位,弱化政府管制对市场的干预具有积极作用。     

Investment in electric energy storage under uncertainty: a real options approach

In this paper we develop a real options approach to evaluate the profitability of investing in a battery bank. The approach determines the optimal investment timing under conditions of uncertain future revenues and investment cost. It includes time arbitrage of the spot price and profits by providing ancillary services. Current studies of battery banks are limited, because they do not consider the uncertainty and the possibility of operating in both markets at the same time. We confirm previous research in the sense that when a battery bank participates in the spot market alone, the revenues are not sufficient to cover the initial investment cost. However, under the condition that the battery bank also can receive revenues from the balancing market, both the net present value (NPV) and the real options value are positive. The real options value is higher than the NPV, confirming the value of flexible investment timing when both revenues and investment cost are uncertain.     

Vector Majorization and a Robust Option Replacement Trading Strategy

We show that vector majorization and its related preference sets can be used to establish useful option pricing bounds for a robust option replacement investment strategy. This robust trading strategy can help to overcome some of the difficulties in implementing arbitrage option trading strategies when there exists model inaccuracy. Dedicated to Boris Mordukhovich on his 60th birthday.     

Asymptotic arbitrage in large financial markets with friction

In the modern version of arbitrage pricing theory suggested by Kabanov and Kramkov the fundamental financially meaningful concept is an asymptotic arbitrage. The ??real world?? large market is represented by a sequence of ??models?? and, though each of them is arbitrage free, investors may obtain non-risky profits in the limit. Mathematically, absence of the asymptotic arbitrage is expressed as contiguity of envelopes of the sets of equivalent martingale measures and objective probabilities. The classical theory deals with frictionless markets. In the present paper we extend it to markets with transaction costs. Assuming that each model admits consistent price systems, we relate them with families of probability measures and consider their upper and lower envelopes. The main result concerns the necessary and sufficient conditions for absence of asymptotic arbitrage opportunities of the first and second kinds expressed in terms of contiguity. We provide also more specific conditions involving Hellinger processes and give applications to particular models of large financial markets.     

流动性能提高套利交易的盈利吗？——基于中国股市的证据

本文以新兴市场重要组成部分之一的中国股市为例,对市场总体流动性水平与套利交易盈利能力间的关系进行了深入分析。与成熟资本市场中的状况相反,本文研究发现,在控制了Fama-French三因子后,套利交易的预期盈利随着市场流动性水平的提高而增加,表明市场异象造成的错误定价并不会随着流动性的提高而被投资者的套利交易所纠正,这体现了不成熟市场的特征,且反映了套利的无效率。另外,本文在分析中还考虑了流动性风险和时变因素风险暴露等可能对研究结论造成影响的因素,并且在进一步研究后得到了与前文相一致的结论。     

Practical arbitrage‐free scenario tree reduction methods and their applications in financial optimization

We construct an arbitrage‐free scenario tree reduction model, from which some arbitrage‐free scenario tree reduction algorithms are designed. They ensure that the reduced scenario trees are arbitrage free. Numerical results show the practicality and efficiency of the proposed algorithms. Results for multistage portfolio selection problems demonstrate the necessity and importance for guaranteeing that the reduced scenario trees are arbitrage free, as well as the practicality of the proposed arbitrage‐free scenario tree reduction algorithms for financial optimization.     

Calculating risk neutral probabilities and optimal portfolio policies in a dynamic investment model with downside risk control

This paper presents a method for solving multiperiod investment models with downside risk control characterized by the portfolio’s worst outcome. The stochastic programming problem is decomposed into two subproblems: a nonlinear optimization model identifying the optimal terminal wealth distribution and a stochastic linear programming model replicating the identified optimal portfolio wealth. The replicating portfolio coincides with the optimal solution to the investor’s problem if the market is frictionless. The multiperiod stochastic linear programming model tests for the absence of arbitrage opportunities and its dual feasible solutions generate all risk neutral probability measures. When there are constraints such as liquidity or position requirements, the method yields approximate portfolio policies by minimizing the initial cost of the replication portfolio. A numerical example illustrates the difference between the replicating result and the optimal unconstrained portfolio.     

Arbitrage and the tax code

We provide a detailed characterization of arbitrage-free asset prices in the presence of capital gains and income taxes. The distinguishing feature of our analysis is that we impose on the model two important features of the tax code: the limited use of capital losses and the inability to wash sell. We show that under remarkably mild conditions, the lack of pre-tax arbitrage implies the lack of post-tax arbitrage with the limited use of capital losses. The conditions are that the risk free interest rate be positive and that tax rates on interest income exceed capital gains tax rates. The result also holds when only a wash sale constraint is imposed and no investor holds a portfolio with a large capital loss. We allow investors to face different tax rates and have different bases for the calculation of capital gains taxes. The characterizations we provide have important implications for both asset pricing and portfolio choice. Our results imply that models that use arbitrage-free pre-tax models continue for derivative pricing and hedging are also arbitrage free in a world with taxes. Similarly, portfolio choice models with taxes typically specify pre-tax arbitrage free price processes and then analyze portfolio choice in the presence of taxes. In these models, it is unclear if portfolio recommendations are based on risk-return tradeoffs or on the arbitrage opportunities present in the model. Our results imply that if the above features of the tax code are modeled explicitly, then we can isolate the post-tax risk-return tradeoffs.     

Arbitrage theory for non convex financial market models

We propose a unified approach where a security market is described by a liquidation value process. This allows to extend the frictionless models of the classical theory as well as the recent proportional transaction costs models to a larger class of financial markets with transaction costs including non proportional trading costs. The usual tools from convex analysis however become inadequate to characterize the absence of arbitrage opportunities in non-convex financial market models. The natural question is to which extent the results of the classical arbitrage theory are still valid. Our contribution is a first attempt to characterize the absence of arbitrage opportunities in non convex financial market models.     

Pricing and hedging in a single period market with random interval valued assets

In this article, a new financial market model, in which securities have random interval valued payoffs, is proposed. As an extension of traditional random market model, some concepts, such as robust arbitrage opportunities, risk-neutral pricing measures and robust replicative strategies, are given and discussed parallel to those in traditional market analysis. With these new concepts, problems of pricing and hedging are analyzed. It is shown that the requirement of no robust arbitrage opportunities is equivalent to the existence of risk-neutral pricing measures. Taking no robust arbitrage as the valuation principle, the problem of pricing a contingent claim with random interval valued payoff is discussed. All no robust arbitrage prices of the claim form an interval, whose endpoints can be got from the risk-neutral pricing measures or from robust replicative strategies.     

套汇问题研究

把套汇问题转化为网络规划中找负回路问题,用F loyd算法解决了套汇问题.讨论了避免套汇兑换率矩阵必须是正互反矩阵的结论,以及给出了兑换率矩阵调整为正互反矩阵的方法.     

Valuation of European options in the market with daily price limit

A valuation problem of the European style contingent claim in the market with daily price movement limit is studied. Unlike the one leading to the well known Black-Scholes formula, this problem depicts considerable conceptual difficulty and anomaly created by the presence of various arbitrage opportunities inherently built in the model due to the daily price movement limit. The presence of arbitrage makes it go against the grain of the well established arbitrage pricing theory. In this paper, how these complications arise are discussed and then a valuation approach devised, which is called the ‘vanishing transaction cost technique,’ of getting around the difficulty.     

Optimal Consumption Portfolio and No-Arbitrage with Nonproportional Transaction Costs

In this paper we consider a finite-state financial market with non-proportional transaction cost and bid-ask spreads. The transaction cost consists of two parts: a fixed cost and a proportional cost to the size of transaction. We show that the existence of an optimal consumption policy implies that the market has no strong arbitrage; the opposite, however, is not true, i.e., no strong arbitrage does not imply the existence of an optimal consumption policy. This is in sharp contrast with the case of proportional transaction cost and other cases reported in the literature, where no strong arbitrage is equivalent to the existence of an optimal consumption policy. We also study the relationship between weak arbitrage and strong arbitrage. Different from the market with proportional transaction cost, we find that these two forms of arbitrage are equivalent unless the fixed cost is zero. A necessary and sufficient condition for the existence of an optimal consumption policy is also obtained. Supported by CAS, NSFC, RGC of Hong Kong and NSF under Grant No. DMI-0196084 and DMI-0200306.