COMPLEX LOGARITHMS IN HESTON‐LIKE MODELS

The characteristic functions of many affine jump‐diffusion models, such as Heston's stochastic volatility model and all of its extensions, involve multivalued functions such as the complex logarithm. If we restrict the logarithm to its principal branch, as is done in most software packages, the characteristic function can become discontinuous, leading to completely wrong option prices if options are priced by Fourier inversion. In this paper, we prove without any restrictions that there is a formulation of the characteristic function in which the principal branch is the correct one. Because this formulation is easier to implement and numerically more stable than the so‐called rotation count algorithm of Kahl and Jäckel, we solely focus on its stability in this paper. This paper shows how complex discontinuities can be avoided in the Variance Gamma and Schöbel–Zhu models, as well as in the exact simulation algorithm of the Heston model, recently proposed by Broadie and Kaya.     

影响证券组合投资三个重要因素分析

在首先分析影响证券组合投资的三个重要因素以及它们的特征后 ,结合事例分析它们是如何影响证券组合投资的 ,最后得出三个重要结论 ,以加强投资者对证券组合理论和实践的认识 ,为证券投资者进行证券选择提供了科学的依据和方法。     

利用样本轮换设计降低调查中的无回答影响

调查中无回答的存在往往是形成一种系统性误差的主要原因。它会造成统计分析结果产生偏差。文章主要讨论如何利用样本轮换技术有效地降低无回答带来的不良影响，从而提高统计估计的精度和分析结果的可靠性。     

Common stochastic trends and the dynamic linkages driving european stock markets: evidence from pre- and post-october 1987 crash eras

Given the impact of the October 1987 crash pre-empting fears of a deep-seated financial collapse, there is now much scope for assessing its importance quantitatively. In this paper, time series techniques are used to analyse the dynamic linkages and propagation of shocks among five European stock markets. While we do not find any long-run relationship of stock markets over the entire sample ped, evidence is found in support of a unique cointegrating vector over each of the pre- and post-crash samples. Furthermore, the dynamic analysis reveals that the lead–lag relationships changed quite significantly over the sample following the crash.     

Option overlay strategies

Option overlays on a rebalanced portfolio are designed. Inputs to the design problem are the physical and risk neutral probabilities at the option maturity. They are estimated from time series and option data, respectively. The objective for the design is the bid price of a two price economy modelled as a distorted expectation. The design is monotone increasing in the underlier with a delta constraint. The option positioning is implemented on the S&P 500 index, supposedly rebalanced every 21 days with option positions taken 10 days prior to a rebalance date with a maturity near two months. Option overlays are seen to raise performance measures and reduce drawdowns.     

Quasi-Monte Carlo methods with applications in finance

We review the basic principles of quasi-Monte Carlo (QMC) methods, the randomizations that turn them into variance-reduction techniques, the integration error and variance bounds obtained in terms of QMC point set discrepancy and variation of the integrand, and the main classes of point set constructions: lattice rules, digital nets, and permutations in different bases. QMC methods are designed to estimate s-dimensional integrals, for moderate or large (perhaps infinite) values of s. In principle, any stochastic simulation whose purpose is to estimate an integral fits this framework, but the methods work better for certain types of integrals than others (e.g., if the integrand can be well approximated by a sum of low-dimensional smooth functions). Such QMC-friendly integrals are encountered frequently in computational finance and risk analysis. We summarize the theory, give examples, and provide computational results that illustrate the efficiency improvement achieved. This article is targeted mainly for those who already know Monte Carlo methods and their application in finance, and want an update of the state of the art on quasi-Monte Carlo methods.      

银行信贷、房地产价格与实际产出关系的经验研究

房地产泡沫破灭将对经济和社会发展带来长期破坏性的影响,甚至可能引发金融危机。文章从投资者的视角将房地产价格做了分解,测度了各因素变化对房地产价格变化的直接贡献和间接贡献,分析了房地产价格快速上涨机制。得出了以下结论:房地产价格存在明显的正反馈效应,信贷规模的增长对房地产价格上涨贡献最大;房地产价格的上涨及上涨预期增加了银行的贷款冲动,刺激了投机需求和地方政府官员的政绩需求,它们共同推动房地产价格和土地交易价格进一步上涨,两者循环作用,最终导致了房地产价格的螺旋式上升。     

Preposterior analysis for option pricing

The second partial derivative of a European-style vanilla option with respect to the current price of the underlying asset—the option gamma—defines a probability density function for the current underlying price. By use of entropy maximization it is possible to obtain an option gamma, from which the associated option pricing formula can be recovered by integration. A number of pricing formulae are obtained in this manner, corresponding to different specifications of the constraints. When the available market information consists solely of a set of traded option prices, the entropic formulation leads to a model-independent calibration procedure. The result thus obtained also allows one to recover the relevant Greeks.     

我国货币政策汇率传导机制有效性的实证研究

本文应用当代主流的计量经济学的研究方法,通过对2002年以来相关的经济金融月度数据的实证分析,探究了我国货币政策传导渠道之汇率传导渠道的运作机制以及传导效果。写作本文的目的不仅在于对汇率传导渠道的有效性得出一个基本判断,而且想借此判断在深入分析的基础上,不断完善我国货币政策传导的微观金融环境,期望进一步推动我国的金融市场建设和金融体制改革。