保费随机收取下带特殊分红策略的复合二项风险模型

本文讨论保费随机收取情形下带特殊分红策略的复合二项风险模型.考虑当盈余大于或等于一个给定的非负红利界并且索赔不发生时保险公司以一定概率给股东分红,得到该模型的罚金函数的递推公式,然后利用矩阵知识证明其存在唯一解,最后给出破产概率、破产时破产赤字分布概率函数的递推公式.     

关于常利率风险模型在破产前后余额的分布

本文对常利率风险模型运用拉普拉斯变换给出了破产前后余额通过破产概率函数表示的有限公式,以及破产概率的分析表达式,另外对于破产前后余额分布的密度与破产前余额密度之间关系简要说明。     

与两种破产类型相关的余额极值联合分布

带干扰古典风险模型具有由索赔和小余额快速变化分别引起的两种破产和相应的破产时间．该文在两种类型破产各自发生的条件下,使用破产概率函数分别就余额过程首次返回零点以及最后一次返回零点所经历的时间间隔,给出了各自的余额最大值和最小值的联合分布．文章还给出了与该风险模型关联密切的若干鞅的表达式．     

一类盈余过程的破产概率及其应用

本文给出了复合Poisson盈余过程在其个体理赔量服从两个指数分布的混合 分布时破产概率的显示解,并研究了此情形下破产概率的Lundberg界.作为应用,给出 了一种计算一般复合Poisson盈余过程破产概率的近似方法.     

改进后的复合Poisson-Geometric风险模型Gerber-Shiu折现惩罚函数

在考虑到因保费收入和通货膨胀等随机干扰的影响,以及将多余资本用于投资来提高赔付能力的基础上,文章对复合Poisson-Geometric风险模型做进一步推广,建立以保费收入服从复合Poisson过程,理赔量服从复合Poisson-Geometric过程的带投资的干扰风险模型,针对该风险模型,应用全期望公式,推导了Gerber-Shiu折现惩罚函数满足的更新方程,进而得到了在破产时盈余惩罚期望,破产赤字和破产概率满足的更新方程.并以保费额和索赔额均服从指数分布为例,给出破产概率满足的微分方程.以及通过数值例子,分析了初始准备金额,投资金额及保费额等对保险公司最终破产概率的影响.结论为经营者或决策者对各种金融或保险风险进行定量分析和预测提供了理论依据.     

马氏环境复合二项模型的条件概率计算北大核心CSCD

肖临在Cossette(2004)的基础上改进并建立了马氏链环境中复合二项风险模型,针对Cossette(2004)中所提出的几个命题在肖临的模型框架下给出了详细的证明,得出了有限时间的条件非破产概率递推公式及赔付额的条件概率函数的递推公式.     

Conditional probability calculations of compound binomial risk model in Markov-chain environment

肖临在Cossette(2004)的基础上改进并建立了马氏链环境中复合二项风险模型,针对Cossette(2004)中所提出的几个命题在肖临的模型框架下给出了详细的证明,得出了有限时间的条件非破产概率递推公式及赔付额的条件概率函数的递推公式.     

带税率的Cramér-Lundberg风险模型的总征税次数的分布函数(英文)

本文研究了带税率的Cramér-Lundberg风险模型.利用迭代算法及该过程具有的的强马氏性,得出了保险公司从开始营运到破产期间总赋税次数的概率函数.作为例子,本文给出了指数分布索赔假定下该概率函数的具体表达式.     

广义Polya-Aeppli分布下相依风险模型的破产概率

本文基于广义Polya-Aeppli分布研究两个赔偿过程具有相关性的破产概率问题.首先,结合Kocherlakota(1995)定义的概率母函数推导一类相依过程的联合概率分布函数及其各阶矩的具体表达式;然后,建立两种情况的破产模型,通过Laplace变换将求解破产概率转换为求解累积赔偿金额的概率分布函数,给出赔偿金额服从指数分布时两类风险模型的破产概率解析表达式.广义Polya-Aeppli分布定义了一类具有相关性的离散分布,克服了已有模型中使用Poisson过程模拟实际数据存在的过分分散问题,且易于进行参数估计,所以本文所得结论具有更广泛的适用性.     

竞争型二元风险模型破产概率

本文研究了竞争型的二元风险模型,定义了两类破产概率以及状态过程,利用经典风险模型的已有结果和条件期望的性质,得到两类破产概率表达式,以及单个保险公司有限时间破产概率和最终破产概率,并给出两个保险公司的状态过程的概率分布列.     

Ornstein-Uhlenback type Omega model

We consider the Omega model with underlying Ornstein-Uhlenbeck type surplus process for an insurance company and obtain some useful results. Explicit expressions for the expected discounted penalty function at bankruptcy with a constant bankruptcy rate and linear bankruptcy rate are derived. Based on random observations of the surplus process, we examine the differentiability for the expected discounted penalty function at bankruptcy especially at zero. Finally, we give the Laplace transforms for occupation times as an important example of Li and Zhou [Adv. Appl. Probab., 2013, 45(4): 1049–1067].     

Omega diffusion risk model with surplus-dependent tax and capital injections

In this paper, we propose and study an Omega risk model with a constant bankruptcy function, surplus-dependent tax payments and capital injections in a time-homogeneous diffusion setting. The surplus value process is both refracted (paying tax) at its running maximum and reflected (injecting capital) at a lower constant boundary. The new model incorporates practical features from the Omega risk model (Albrecher et al., 2011), the risk model with tax (Albrecher and Hipp, 2007), and the risk model with capital injections (Albrecher and Ivanovs, 2014). The study of this new risk model is closely related to the Azéma–Yor process, which is a process refracted by its running maximum. We explicitly characterize the Laplace transform of the occupation time of an Azéma–Yor process below a constant level until the first passage time of another Azéma–Yor process or until an independent exponential time. We also consider the case when the process has a lower reflecting boundary. This result unifies and extends recent results of Li and Zhou (2013) and Zhang (2015). We explicitly characterize the Laplace transform of the time of bankruptcy in the Omega risk model with tax and capital injections up to eigen-functions, and determine the expected present value of tax payments until default. We also discuss a further extension to occupation functionals through stochastic time-change, which handles the case of a non-constant bankruptcy function. Finally we present examples using a Brownian motion with drift, and discuss the pricing of quantile options written on the Azéma–Yor process.     

考虑破产风险约束的多项目投资组合决策模型

项目投资决策不导致破产事件的发生,是投资者获得预期收益的前提,故控制破产事件发生的概率至关重要。鉴于此,本文基于可信性测度理论,根据Roy的定义给出了未来现金流量隶属三角模糊变量的控制破产风险的数学表达式,并构建了项目投资过程中受到破产风险因素影响的具有破产风险约束的多项目投资组合决策模型。最后,运用遗传算法对模型进行求解,并给出算例演示本文模型的实用性和有效性。     

实时定期人寿保险的破产模型及破产概率的计算

研究定期人寿保险中破产风险问题。建立了该类问题的数学模型,并分析其结构特征,推导破产概率的计算公式,并设计其计算方法。同以往模型相比,新模型的建立考虑了初始准备金的利息积累和任何时刻的新投保人的加入,采用了新的分组方式。这种新模型更加真实地刻画了实际过程,保证了传统模型中常用的某些假设得到了满足。     

考虑利率因素的保险破产模型研究

本文首先介绍了在一般化破产模型基础上够造的保险费收取次数为Poisson过程的破产模型,并进一步在此模型上考虑了利率因素,使得相应的破产概率更具有实际意义。     

带干扰的复合广义齐次Poisson过程的多险种破产概率

将复合广义齐次poisson过程的多险种风险模型推广到带干扰的一种新模型,运用鞅方法破产概率满足的Lundberg不等式和一般公式.     

不确定环境下定期人寿保险的破产概率区间的计算

针对实际问题存在的不确定因素,研究了含不确定参数的定期人寿保险的破产模型,其中死亡率和净年保单数分别用区间数和随机参数刻画.推导了破产概率区间的计算公式,且用泊松分布近似时得到其近似计算方法.该模型的建立既考虑了初始准备金的利息积累和任何时刻的新投保人的加入,并采用了新的分组方式,又考虑了实际问题中的不确定因素,因而能够更加真实地刻画了实际过程,比传统模型更具实用性.     

Worst-case robust Omega ratio

The Omega ratio is a recent performance measure proposed to overcome the known shortcomings of the Sharpe ratio. Until recently, the Omega ratio was thought to be computationally intractable, and research was focused on heuristic optimization procedures. We have shown elsewhere that the Omega ratio optimization is equivalent to a linear program and hence can be solved exactly in polynomial time. This permits the investigation of more complex and realistic variants of the problem. The standard formulation of the Omega ratio requires perfect information for the probability distribution of the asset returns. In this paper, we investigate the problem arising from the probability distribution of the asset returns being only partially known. We introduce the robust variant of the conventional Omega ratio that hedges against uncertainty in the probability distribution. We examine the worst-case Omega ratio optimization problem under three types of uncertainty – mixture distribution, box and ellipsoidal uncertainty – and show that the problem remains tractable.     

Predicting the event and time horizon of bankruptcy using financial ratios and the maturity schedule of long-term debt

We study the problem of simultaneous and coherent assessment the probability of a firm’s bankruptcy at various time horizons in future. In contrast with usual (one-period) formulations of the problem, such multi-period formulation better matches the nature of bankruptcy process (bankruptcy occurs in time) and allows an easier and more natural incorporation of bankruptcy (default) prognoses in valuation of risky debt and equity, optimization of corporate capital structure etc. The study uses a new mathematical apparatus—multi-alternative decision rules of statistical decision theory. We investigate a new type of predictive variables that can be extracted from the maturity schedule of a firm’s long-term debt. The study develops Bayesian-type forecasting rules that use both maturity schedule factors and traditional financial ratios. These rules noticeably enhance bankruptcy prediction (compared with the familiar one-period Z-score rules of Altman) for bankruptcy within the first 1, 2 or 3 years. Predictive factors derived from schedule information enhance bankruptcy prediction at distant time horizons.     

Infinite-horizon investment consumption model with a nonterminal bankruptcy

This paper solves a general continuous-time consumption and portfolio decision problem for a single agent for whom there exists, upon bankruptcy, a possibility of recovery from his bankruptcy. The main contribution of the paper is in the modeling of the recovery process. Moreover, it is shown that the model with recovery has a one-to-one correspondence with the model with terminal bankruptcy treated in the literature.This research was supported by Grants SSHRC-410-83-9888 and NSERC-A4619 to the first author and by Grants NSF-DMS-86-01510 and AFOSR-88-0183 to the second author. Comments from E. Presman are gratefully acknowledged.