宏观经济变量影响下的银行极端操作风险研究

操作风险管理是当前金融和监管机构密切关注的焦点,但其低频高危数据的严重缺失一直阻碍着极端操作风险度量模型的应用.本文构建了考虑发生频度的复合泊松过程应用模型,从广义帕累托分布(GPD)与广义极值分布(GEV)两种角度度量商业银行的极端操作风险.通过采用国际活跃银行的资本市场数据,基于宏观经济变量影响的Fama-French多因素模型,剥离传统的市场风险、信用风险以及流动性风险等获得综合操作风险极端数据,模拟测度外部事件影响下的银行极端操作风险发现:基于POT(过阈值峰值模型)方法估算的OpCVaR(操作风险的条件在险价值)高于其累积的在险价值,而BMM(分块极值模型)方法提供了一定期限内金融机构的最大损失额频度;且实证分析发现中资银行就其外部宏观经济影响下的极端操作风险而言,普遍低于其国际同行,但排除此次金融危机的系统性影响,则国际活跃银行的风控能力更稳定,这对改善我国银行操作风险管理和监管极具实践意义.     

股票市场的极值风险测度及后验分析研究

通过对上证综指和世界股市若干重要指数的实证研究发现,无论是在成熟资本市场还是新兴资本市场当中,极值理论(EVT)及其工具都能更加准确地刻画实际市场的极端波动和风险状况.详细说明了不同收益分布假定下风险价值(VaR)的计算方法及其后验分析(Back-testing)过程,证明了与非条件和条件正态分布以及条件t分布等主流金融理论的收益分布假定相比,条件EVT分布在测度极端市场风险时所表现出的优越性,同时说明了在不同概率水平下各种收益分布假定的精确度和适用范围.     

POT模型在商业银行操作风险度量中的应用

操作风险发生的频率较低,但可能会引起巨大的损失,其损失分布具有鲜明的厚尾性,因此应用通常的风险计算方法往往会低估风险.而应用极值理论计算风险时注重对分布尾部的近似表达,并不是对整个分布进行建模,能更有效地捕捉可能导致金融机构重大损失的尾部风险.所以,把极值理论应用于银行操作风险量化分析不失为一种比较理想的方法.     

POT模型在商业银行操作风险度量中的应用

操作风险发生的频率较低,但可能会引起巨大的损失,其损失分布具有鲜明的厚尾性,因此应用通常的风险计算方法往往会低估风险.而应用极值理论计算风险时注重对分布尾部的近似表达,并不是对整个分布进行建模,能更有效地捕捉可能导致金融机构重大损失的尾部风险.所以,把极值理论应用于银行操作风险量化分析不失为一种比较理想的方法.     

基于极值理论生鲜乳市场风险评估研究

本文采用极值理论(EVT),对中国生鲜乳市场进行尾部数据拟合,通过超越阀值模型(POT)选取阀值,并在广义帕累托分布(GPD)模型下计算中国生鲜乳市场价格风险(Va R)。结果显示,生鲜乳市场价格波动剧烈。同时,预测生鲜乳价格市场十年一遇、百年一遇情况下生鲜乳价格最大波动幅度或称风险价值。     

基于EVT-POT-SV-MT模型的极值风险度量

针对金融资产收益的异常变化,采用SV-MT模型对风险资产的预期收益做风险补偿并捕捉收益序列的厚尾性、波动的异方差性等特征,将收益序列转化为标准残差序列,通过SV-MT模型与极值理论相结合拟合标准残差的尾部分布,建立了一种新的金融风险度量模型——基于EVT-POT-SV-MT的动态VaR模型.通过该模型对上证综指做实证分析,结果表明该模型能够合理有效地度量上证综指收益的风险.     

基于BS抽样与分段定义损失强度操作风险度量

银行的操作风险管理在我国起步晚,记录损失事件的数据库不健全,而操作风险事件的"低频高损"特征直接导致研究数据不足.针对操作风险样本数据少以及操作风险损失分布的偏峰厚尾和"低频高损"特征,对我国银行业操作风险,采用基于Bootstrap抽样与分阶段定义损失强度的损失分布法(BS-PSD-LDA)进行了度量.将操作风险损失分为高频低损和低频高损两个序列,分别用对数正态分布和广义Pareto分布对两个阶段的操作风险损失分布进行拟合,并在此基础上度量操作风险年损失.收集了我国银行业过去15年期间的操作风险损失样本数据426个,采用该方法度量了其年风险损失,并与历史模拟法、单一对数正态分布法、单一广义Pareto分布法和传统的两阶段分布法(PSD-LDA)度量的结果进行了比较,结果表明,提出的度量方法能够更好地度量我国银行业操作风险,为银行操作风险的度量提供了一种改进方法.     

基于ARIMA-GARCH模型和极值理论的中国股市风险价值度量

以极值理论为基础的风险值度量方法是最近发展起来的最为有效的方法之一,但在传统的单纯采用极值理论的建模过程中对误差项假定为独立同分布的白噪声过程,会对应用极值理论估算风险价值产生一定误差。本文以上证指数和深证成指为例,利用ARIMA-GARCH模型捕获股票收益序列中的自相关和异方差现象,对该模型中残差的条件分布的合理假定进行了实证分析比较,然后利用极值理论对经过ARIMA-GARCH模型筛选过的残差进行极值分析,估算风险价值。     

融资租赁中利率变化对出租人收益影响及对策分析

为了规避融资租赁中利率上升给出租人收益带来损失的风险,本文从出租人角度采用贴现现金流量分析法构建了出租人的收益函数,分析了贷款利率上升时3种不同的租赁费率调整方法对出租人自身收益的影响,并利用MATLAB软件对收益函数进行编程,输出了出租人的收益一利率曲线图.最后得出结论:只有按照市场贷款利率的上升而等比例地调整融资租赁费率时,出租人的收益才会增加.     

VaR方法对证券资产组合风险价值计算的应用

VaR(Value at Risk)即"在险价值"或者"风险价值"。本文将利用VaR方法对我国证券市场上的证券组合的风险价值进行计算,具体选取了博时主题、嘉实300(指数型)、南方绩优成长基金这三支股票488天内每日的开盘价、收盘价及涨跌幅度数据。通过构建方差-协方差矩阵,运用matlab软件编译,得到对这三支组成的资产组合进行投资时所承担的最大可能损失。     

基于幂风险谱和蒙特卡洛模拟的贷款优化配置模型

极端风险对于银行资产配置至关重要，尤其是次贷危机之后尾部风险以惨重的代价引起了金融机构的重视，传统条件风险价值CVaR、风险价值VaR不能有效度量尾部极端风险，因此本文基于幂风险谱和蒙特卡洛模拟构建了贷款组合优化配置模型，同时控制尾部极端风险和信用风险。本文一是通过损失-X_i越大、其风险权重φ_i也就越大的思路，构建幂风险谱PSR （Power Spectral Risk）最小的目标函数对极端风险进行控制，即弥补了CVaR同等看待尾部风险、忽略风险较大的损失应予以更大权重的不足，也同时弥补了VaR仅提供某一置信水平下资产损失的最大值、无法反映一旦超过这一数值的可能损失的弊端。二是通过蒙特卡洛模拟信用等级迁移引起贷款收益的变化情景，并以信用等级迁移后贷款组合损失越大、则风险厌恶权重越大的思路构建幂风险谱PSR最小为目标函数，以贷款组合的收益大于目标收益为约束，构建贷款优化配置模型，改变了现有研究贷款配置时没有同时控制信用风险和尾部风险的不足。对比分析结果表明：本文模型能够实现更高的收益风险比，即在单位幂风险谱PSR下能够实现较高的收益。     

Quantile Uncertainty and Value‐at‐Risk Model Risk

This article develops a methodology for quantifying model risk in quantile risk estimates. The application of quantile estimates to risk assessment has become common practice in many disciplines, including hydrology, climate change, statistical process control, insurance and actuarial science, and the uncertainty surrounding these estimates has long been recognized. Our work is particularly important in finance, where quantile estimates (called Value‐at‐Risk) have been the cornerstone of banking risk management since the mid 1980s. A recent amendment to the Basel II Accord recommends additional market risk capital to cover all sources of “model risk” in the estimation of these quantiles. We provide a novel and elegant framework whereby quantile estimates are adjusted for model risk, relative to a benchmark which represents the state of knowledge of the authority that is responsible for model risk. A simulation experiment in which the degree of model risk is controlled illustrates how to quantify Value‐at‐Risk model risk and compute the required regulatory capital add‐on for banks. An empirical example based on real data shows how the methodology can be put into practice, using only two time series (daily Value‐at‐Risk and daily profit and loss) from a large bank. We conclude with a discussion of potential applications to nonfinancial risks.     

基于VaR的我国商品期货市场风险的预警研究

本文以郑州商品交易所的硬麦期货和上海期货交易所的铜期货为例,构造了期货合约收益率连续时间序列,计算了序列的VaR值,对预测结果的有效性进行了检验,并提出了将VaR曲线和保证金水平相结合的方法,对商品期货市场风险进行单指标预警.     

Stable and Coordinating Contracts for a Supply Chain with Multiple Risk‐Averse Suppliers

We analyze a decentralized supply chain with a single risk‐averse retailer and multiple risk‐averse suppliers under a Conditional Value at Risk objective. We define coordinating contracts and show that the supply chain is coordinated only when the least risk‐averse agent bears the entire risk and the lowest‐cost supplier handles all production. However, due to competition, not all coordinating contracts are stable. Thus, we introduce the notion of contract core, which reflects the agents' “bargaining power” and restricts the set of coordinating contracts to a subset which is “credible.” We also study the concept of contract equilibrium, which helps to characterize contracts that are immune to opportunistic renegotiation. We show that, the concept of contract core imposes conditions on the share of profit among different agents, while the concept of contract equilibrium provide conditions on how the payment changes with the order quantity.     

基于Mean-CVaR约束的股指期货动态套期保值模型研究

本文建立了基于最小化均值-条件风险价值( Mean-CVaR)的股指期货动态套期保值模型.模型的主要特点与贡献在于两方面:一方面,考察了置信水平和可变交易费用对最优套期保值决策的影响;另一方面,利用二元误差修正的时变条件相关GARCH模型估计套期保值比率,优点是不仅考虑了股指期货与现货价格序列之间存在的协整关系,而且更好地拟合了收益残差序列存在的异方差性与相关系数时变性的特征.最后通过对我国沪深300指数期货仿真交易的套期保值模拟与实证测算,得出能够动态调整的股指期货套期保值策略以实时追踪与控制风险.     

Trust,Emotion, Sex,Politics, and Science: Surveying the Risk-Assessment Battlefield

Risk management has become increasingly politicized and contentious. Polarized views, controversy, and conflict have become pervasive. Research has begun to provide a new perspective on this problem by demonstrating the complexity of the concept risk and the inadequacies of the traditional view of risk assessment as a purely scientific enterprise. This paper argues that danger is real, but risk is socially constructed. Risk assessment is inherently subjective and represents a blending of science and judgment with important psychological, social, cultural, and political factors. In addition, our social and democratic institutions, remarkable as they are in many respects, breed distrust in the risk arena. Whoever controls the definition of risk controls the rational solution to the problem at hand. If risk is defined one way, then one option will rise to the top as the most cost-effective or the safest or the best. If it is defined another way, perhaps incorporating qualitative characteristics and other contextual factors, one will likely get a different ordering of action solutions. Defining risk is thus an exercise in power. Scientific literacy and public education are important, but they are not central to risk controversies. The public is not irrational. Their judgments about risk are influenced by emotion and affect in a way that is both simple and sophisticated. The same holds true for scientists. Public views are also influenced by worldviews, ideologies, and values; so are scientists' views, particularly when they are working at the limits of their expertise. The limitations of risk science, the importance and difficulty of maintaining trust, and the complex, sociopolitical nature of risk point to the need for a new approach—one that focuses upon introducing more public participation into both risk assessment and risk decision making in order to make the decision process more democratic, improve the relevance and quality of technical analysis, and increase the legitimacy and public acceptance of the resulting decisions.     

应用复合极值理论估计动态流动性调整VaR

本文首次将一分钟内的交易差价(分内价差)的分布和日收益率的分布结合了起来进行分析,应用复合极值理论给出了动态流动性调整的VaR一种估计,同时得到动态流动性调整VaR的预测方法,最后对上海汽车股票(600104)和中国石化(600028)两只股票进行了实证分析。     

Spatial Risk Analysis of Power Systems Resilience During Extreme Events

The increased frequency of extreme events in recent years highlights the emerging need for the development of methods that could contribute to the mitigation of the impact of such events on critical infrastructures, as well as boost their resilience against them. This article proposes an online spatial risk analysis capable of providing an indication of the evolving risk of power systems regions subject to extreme events. A Severity Risk Index (SRI) with the support of real‐time monitoring assesses the impact of the extreme events on the power system resilience, with application to the effect of windstorms on transmission networks. The index considers the spatial and temporal evolution of the extreme event, system operating conditions, and the degraded system performance during the event. SRI is based on probabilistic risk by condensing the probability and impact of possible failure scenarios while the event is spatially moving across a power system. Due to the large number of possible failures during an extreme event, a scenario generation and reduction algorithm is applied in order to reduce the computation time. SRI provides the operator with a probabilistic assessment that could lead to effective resilience‐based decisions for risk mitigation. The IEEE 24‐bus Reliability Test System has been used to demonstrate the effectiveness of the proposed online risk analysis, which was embedded in a sequential Monte Carlo simulation for capturing the spatiotemporal effects of extreme events and evaluating the effectiveness of the proposed method.     

多重关联关系下供应链上关联信用风险的传染效应

供应链企业之间的多重关联关系导致其信用风险传染愈加复杂。本文基于供应链双渠道融资模式,针对供应链上同时存在交易关联、资产关联和人际关联等三重关联关系的情景,揭示了关联信用风险微观传染机理,构建了关联信用风险传染强度模型,分别探讨了三种关联关系以及链外市场对传染效应的影响。为研究关联信用风险传染的外溢效应,在银行未识别出供应链上关联关系时,探讨了银行面临的期望损失。结合仿真分析发现,相较于单一商业信用融资,双渠道融资模式下传染效应更弱;在最优交易关联强度下,商业信用额度和成本（反映了供应链上的一种资产关联关系）在不同方向上对传染效应产生影响,人际关联关系以及链外市场均负向影响传染效应;银行期望损失则与贷款利率和贷需比相关,人际关联关系将导致银行更大的潜在损失。