基于相对VaR的信用担保两期定价模型

基于风险价值(VaR)计量模型的信用担保定价方法包括绝对VaR和相对VaR两种方法.对于贷款期限一年以上的风险衡量,相对VaR比绝对VaR更加准确和接近现实.针对现有研究中基于绝对 VaR的只考虑原债务期的信用担保风险计量模型的缺陷,本文采用相对VaR方法,建立了既考虑企业对银行的原债务期风险,又考虑企业对担保机构的债务展期风险的信用担保两期定价模型,从而使基于VaR模型的信用担保定价方法更加科学合理.     

基于CAViaR的DCC模型及其对中国股市的实证研究

VaR是金融风险度量方面研究的热点.CAViaR模型可以用来直接计算单个资产的VaR,DCC模型可以用于刻画资产间的相关性.结合这两个模型,通过分位数估计方差的方法,提出了基于CAViaR的DCC模型来计算投资组合的VaR.对中国股市的实证研究表明其具有更好的效果.     

核密度估计在预测风险价值中的应用

通过研究核密度估计理论,提出了一种适应估计金融时间序列分布的L ap lace核密度函数.在单变量核密度估计的基础上建立了风险价值(V a lua at R isk,简记为VaR)预测的预测模型.通过对核密度估计变异系数的加权处理建立了两种加权VaR预测模型.最后,通过上证指数收益率对建立的VaR预测模型进行了实证分析,结果显示两种加权方法对上证指数收益率的VaR预测具有较高的效率.     

基于非正态分布的投资组合VaR分解

在阐述了投资组合边际VaR、成分VaR和增量VaR之间相互关系的基础上,给出了资产收益率服从非正态分布下投资组合分解的一种新方法,结果发现它与正态方法下投资组合分解的结论一致,并结合实证研究验证了结论的正确性.     

均值-VaR模型的一种新解法：鞍点近似、遗传算法

以均值度量收益,方差度量风险的均值.方差模型,广泛应用于资产组合优化.随着对金融风险度量方法研究的不断深入,VaR作为一种简便、易于理解的风险度量方法,在金融企业中得到日益广泛的应用.本文用VaR代替均值-方差模型中的方差,构建了均值-VaR模型应用干投资组合优化.均值-VaR模型是非线性规划,仅当VaR满足凸性和可微性的前提下,满足库恩-塔克条件的解才是全局最优解.本文在CreditRisk+框架下,提出一个在不允许卖空条件下,不需对VaR的性质做出前提假定的新解法:将鞍点近似法用于计算VaR,在资产头寸与VaR之间建立起函数关系,采用遗传算法寻找模型的近似最优解.并用一个债券组合说明该方法的有效性。     

平稳序列BMM模型与沪深股市极端风险研究

基于VaR理论正态分布假设导致的尾部风险低估问题,研究了GEV分布下的BMM模型及区间关联下的极值VaR的建模,并实证分析了沪深股市极端风险.研究结果表明:BMM模型对金融风险的厚尾具有更合理的理论基础.然而,涨跌停板极大地抑制了沪深股市极值数据的异质性,形成"极值不极"现象,导致在较高置信度下BMM模型更为有效,而在较低置信度下反而存在低估问题,有效性尚不及VaR模型.     

Copula界在多元VaR中的应用

首先介绍了多元随机变量和的边界,以及由此导出的VaR边界,然后全面总结了有关Copula下界的公式,而Copula下界及其对偶函数分别构成计算VaR边界的依据.最后根据VaR边界的数值算法,针对不同的Copula下界,分多种情景详细分析了VaR的边界范围.关于上证指数和深成指数收益率序列的实证分析发现.Spearman相关系数和正象限相依对VaR界的收窄作用最强.     

商业银行中VaR估值方法的检验

VaR模型,作为商业银行风险管理的重要工具之一,能较为准确地测量资产组合在金融市场正常波动下的市场风险.然而,在实际应用中,VaR模型仍存在一些缺陷,例如,在极端市场情况下,VaR存在较大的估计误差.压力测试,作为VaR模型的一个补充,可以用来测量极端市场状况下的金融市场风险.回溯测试,则可以用来检验VaR模型的准确性.巴塞尔委员会也对VaR模型制定了最低使用标准,文章最后将对此予以简单介绍并对我国商业银行在模型实施上提出一些建议.     

正相协下风险度量VaR样本分位数估计的渐近性质

本文研究了正相协严平稳样本下,风险度量VaR样本分位数估计的问题.利用其指数不等式和协方差不等式,获得了风险度量VaR的样本分位数估计的相合性和渐近正态性,并给出Bahadur表示.     

不同市态下正态性转换时变VaR

VaR技术作为全球广为流行的金融风险管理技术,其测度的是极端情况下的风险头寸,但在传统假设下可能会极大地低估其值,这就会使得在实践中使用VaR值作为风险管理标准时面临更大的新的风险.考虑我国股市处于不同市场态势下对风险头寸的影响,就牛、熊市中分别估测VaR值.首先利用各种Delta-Gamma-Johnson转换函数对经验数据进行正态性调整.考虑通过转换机制调整后的经验数据仍然存在的异方差性特征,然后运用GARCH模型计算时变VaR值,以此来改善VaR的计算风险,探讨我国股票市场VaR技术的适用性和准确性.     

固定汇率制度下的双币种交换期权

在固定汇率制度模型的基础上,利用计价单位变化以及风险中性概率测度,得到固定汇率制度下的双币种交换期权价格的闭式解．     

An analytic valuation method for multivariate contingent claims with regime-switching volatilities

In this paper, we provide an analytic valuation method for European-type contingent claims written on multiple assets in a stochastic market environment. We employ a two-state Markov regime-switching volatility in order to reflect stochastically changing market conditions. The method is developed by exploiting the probability density of the occupation time for which the underlying asset processes are in a certain regime during a time period. In order to show its usefulness, we derive analytic valuation formulas for quanto options and exchange options with two underlying assets, as examples.     

Robust international portfolio management

We present an international portfolio optimization model where we take into account the two different sources of return of an international asset: the local returns denominated in the local currency, and the returns on the foreign exchange rates. The explicit consideration of the returns on exchange rates introduces non-linearities in the model, both in the objective function (return maximization) and in the triangulation requirement of the foreign exchange rates. The uncertainty associated with both types of returns is incorporated directly in the model by the use of robust optimization techniques. We show that, by using appropriate assumptions regarding the formulation of the uncertainty sets, the proposed model has a semidefinite programming formulation and can be solved efficiently. While robust optimization provides a guaranteed minimum return inside the uncertainty set considered, we also discuss an extension of our formulation with additional guarantees through trading in quanto options for the foreign assets and in equity options for the domestic assets.     

国内外利率为随机的双币种重置型期权定价

双币种重置期权的特征是指在终端期T时的收益依赖于预先设定的t<,0>时刻标的资产的价格与执行价K>0(事先给定)的大小关系重新设置期权的执行价从而给出其定价,这种期权是投资于外国资产的一种合约,其风险不仅依赖外国资产价格的变化,还受外国货币的汇率以及国内外两种利率波动的影响,所以在实际应用方面十分广泛.本文首先就标的资...     

Sull'inversione del teorema di Menabrea nella statica termoelastica semilinearizzata

Sunto. Questa Nota completa, in un certo senso, una mia recente Memoria, in quanto accerta che l'intervento di legami [o vincoli] unilaterali non esclude neppure l'inversione del teorema di Menabrea. A Enrico Bompiani in occasione del suo Giubileo scientifico.     

基于CvaR的融入期权的投资组合模型

把期权作为一种投资对象融入到投资组合中,而不仅仅是作为风险对冲工具.用条件风险价值(CVaR)刻画组合风险,并求出最小化风险下的最优鲁棒投资组合策略.最后通过数值算例证明了模型的有效性,并得到融入期权后有效地提高了组合的收益,特别是当标的资产出现大的波动时,期权在组合中的表现更突出.     

Trasformazioni termoelastiche finite

Sunto Questa Memoria, a differenza delle precedenti (*), apertamente si rivolge ai solidi elastici vincolati anche in superficie — magari unilateralmente — completundo e assai estendendo quanto già figura in mie pubblicazioni (**) del 1959. A Giovanni Sansone nel suo 70^mo compleanno.     

Optimization of covered call strategies

We present a risk-return optimization framework to select strike prices and quantities of call options to sell in a covered call strategy. Covered calls of a general form are considered where call options with different strike prices can be sold simultaneously. Tractable formulations are developed using variance, semivariance, VaR, and CVaR as risk measures. Sample expected return and sample risk are formulated by simulating the price of the underlying asset. We use option market price data to perform the optimization and analyze the structure of optimal covered call portfolios using the S&P 500 as the underlying. The optimal solution is shown to be directly linked to the options’ call risk premiums. We find that from a risk-return perspective it is often optimal to simultaneously sell call options of different strike prices for all risk measures considered.     

A systematic approach to pricing and hedging international derivatives with interest rate risk: analysis of international derivatives under stochastic interest rates

This paper deals with the valuation and the hedging of non-path-dependent European options on one or several underlying assets in a model of an international economy allowing for both, interest rate risk and exchange rate risk. Using martingale theory and, in particular, the change of numeraire technique we provide a unified and easily applicable approach to pricing and hedging exchange options on stocks, bonds, futures, interest rates and exchange rates. We also cover the pricing and hedging of compound exchange options.     

American options under uncertain volatility

The uncertain volatility approach to financial derivatives is extended to American options (which allow early exercise before expiry). The requirement to model at the portfolio level made necessary by the non-linearity of the approach is found to lead to a recursive structure to the exercise possibilities across options. Other novel features include: the optimality sometimes of partial exercise; an interesting resolution to the issues surrounding short options whose exercise is controlled by a buyer counterparty; and the occurrence of a simple game structure for portfolios containing both long and short options. It is demonstrated that the exercise strategies resulting can significantly alter measured uncertain volatility risk. Contrary to the set of attributes for sensible risk measures put forward by Artzner, Delbaen, Eber and Heath, this risk need not be homogenous in portfolio size- forming a convincing argument for weakening this particular requirement.