基于效用的永久性可转换债券定价

在不完备市场条件下,假设公司价值可以观测,公司只发行股票和不可赎回、不可违约的具有固定券息的永久性可转换债券,债券持有人有权利(但没有义务)按一定比例将债券转换为股票.基于可转换债券的结构式定价模型,给出债券持有人的最优转换策略,推导出可转换债券消费效用无差别价格的半封闭式解,利用有限差分方法,得到可转换债券的隐含价值(即消费效用无差别价格)以及可转换债券的最优消费策略和转换策略的数值解.研究结果表明,债券持有人的风险态度和非系统风险对最优转换策略和可转换债券的隐含价值有显著影响,与完备市场条件相比,风险厌恶情形可转换债券的转换触发水平和隐含价值较低,风险资产价格波动率越大,可转换债券的隐含价值越大.     

巨灾风险债券定价

巨灾风险债券通过证券化将风险转移到资本市场,投资者可以利用巨灾债券与经济变量无关的特性,获取不受金融市场变量影响的高收益.本文推导了一个不完全市场框架下的基于代表性代理模型基础上的巨灾风险债券定价模型.     

市场风险与违约风险同时存在下的最优资产配置

本文研究了当投资者同时面临市场风险(利率风险)和违约风险时,如何对可违约债券、国债、股票以及银行存款进行最优配置的问题。利用简约化模型来刻画可违约债券的违约风险,并给出其价格的动态方程。通过鞅方法给出了此优化问题的解析解,结果表明:股票的最优投资策略与Merton模型的结果相同;国债的最优投资策略是利率风险溢价的增函数;可违约债券的最优投资策略与跳跃(违约)风险溢价密切相关,只有当可违约债券的跳跃风险溢价大于1,即市场对跳跃风险进行风险补偿时,投资者才会持有可违约债券;否则,投资者对可违约债券的最优投资为零。     

债券流动性与违约风险相关性溢价及实证研究

债券的流动性与违约风险都是影响债券溢价的重要因素,然而以往在违约风险最为突出的公司债券定价中却很少考虑两种风险相关性关系的影响,这与发达市场实证经验不符.在已有研究的基础上同时引入两种风险相关性,通过对Copula函数刻画的不同相关性结构情况下公司债券的收益率和风险变化分析,以及对中国短、中、长期公司债券市场数据的实证检验均发现,流动性与违约风险的相关性之间存在显著的正相关性,且对债券利差具有显著的影响和交互作用.     

论保险公司的巨灾风险管理——再保险方法与风险证券化

随着时代发展,经济中出现各种风险损失规模也日益增大,因此保险公司在面临巨灾时可能出现承保以及偿付能力不足的情况。为了管理巨灾风险,保险公司可以使用再保险方法,但该方法仍存在一定局限。因此,使用以巨灾债券为代表的风险证券化方法成为国际保险市场的新动态。巨灾债券通过引入资本市场资金以扩大保险市场的风险容量并实现了巨灾风险的转移及扩散。而资本市场引入巨灾债券也被证明是对投资组合的优化。风险证券化的应用在我国有着广大的发展前景。     

可违约零息债券风险综合度量Monte Carlo方法

可违约零息债券同时面临着违约风险和市场风险(利率风险)这两类主要风险.相对于传统的不同类风险独立度量方法,也不同于割裂两类风险再进行加总或通过Copula函数关联,本文在信用风险强度定价模型的基础上,同时考虑信用风险、市场风险和两类风险之间的相关关系,建立了计算可违约零息债券综合风险VaR的Monte Carlo方法,得出同一个风险计算期下反映两类风险的损失分布和同一个某置信度的损失分布的分位点,进而能求得风险综合VaR值,这样可在同一个框架下同时捕捉可违约零息债券的两类风险,这里,给出了MonteCarlo模拟方法具体技术细节,包括违约时间和基础状态向量过程的模拟.最后运用本文的风险综合度量模型对短期融资券的综合风险进行计算,得出风险综合VaR值,并与利率风险独立度量VaR值和信用风险独立度量VaR值进行比较分析.     

非平移收益曲线的风险免疫策略

在债券收益曲线呈刚体运动的假设条件下,引入Fisher&Weil久期的概念.从收益曲线的运动分析出发,提出了非平移收益曲线的风险免疫模型,基于该模型研究了风险最小化债券组合的对冲技术和方法.通过数值模拟实验,采用风险值VaR次序统计量估计技术对不同免疫策略下债券组合的风险敞口进行了分析.结果表明,所提出的风险免疫策略能有效地防范和控制无违约债券的利率风险.     

随机利率条件下可转换债券定价模型的经验检验

本文运用市场的实际数据对随机利率条件下可转换债券的定价模型作了经验检验,发现在可卖空的市场条件下,对处于实值状态的可转换债券可直接获得满意的定价,对处于虚值状态的可转换债券需要考虑债券的恶意违约风险,在加入风险补偿后也可获得满意的定价。在中国不可卖空的市场条件下,这一定价模型仅对进入转换期的可转换债券的价格具有一定的预测作用。     

独善其身还是唇亡齿寒：股价崩盘风险是否影响债券定价?

本文考察了在同一发行主体下,股价崩盘风险对债券定价的溢出效应。研究结果表明,当公司股价崩盘风险上升时,公司债券的表现也不能做到独善其身。股价崩盘风险越高的企业,其发行的债券在二级市场上的信用利差越高,而且这一效应在民营企业债券和低信用评级债券样本中的溢出程度更大。进一步的检验还显示:在风险承担水平较高、内部控制质量较差、会计信息不确定性越高的公司中,股价崩盘风险对债券信用利差的正向影响更为显著。本文从微观主体的角度考察了上市公司股价崩盘风险的经济后果,拓展了债券信用利差的跨市场影响因素研究,有助于理解中国股票和债券市场之间的联动关系,对于降低公司债券违约风险、维护资本市场平稳发展具有一定的启示意义。     

信用风险下基于Black-Scholes的可转换债券定价模型及应用研究

由于我国可转换债券定价理论没有被充分挖掘,出现了可转换债券的市场定价偏低,收益风险不匹配,忽视信用风险的影响等问题.本文借鉴国外可转换债券定价理论,在B1ack-schoIes模型的基础上,根据我国可转换债券市场的特点,并考虑信用风险的影响,建立了适应我国可转换债券实际情况的模型,并进行了实际验证,取得了良好的效果.模型对我国可转债投资者和发行者具有重大指导意义,而且对我国可转债市场的健康发展具有借鉴意义.     

Summarizing Risk Using Risk Measures and Risk Indices

Our society is fascinated with risk in many different areas and disciplines. One of the main ways to describe and communicate the level of risk is through risk indices, which summarize risk using numbers or categories such as words, letters, or colors. These indices are used to communicate risks to the public, understand how risk is changing over time, compare among different risks, and support decision making. Given the different methods to construct risk indices, including flawed methods such as risk matrices, this article develops specific steps that analysts can follow to create a risk index. This article emphasizes the importance of describing risk with a probability distribution, developing a numerical risk measure that summarizes the probability distribution, and finally translating the risk measure to an index. Measuring the risk is the most difficult part and requires the analyst to summarize a probability distribution into one or possibly a few numbers. The risk measure can then be transformed to a numerical or categorical index. I apply the method outlined in this article to construct a risk index that compares the risk of fatalities in aviation and highway transportation.     

Characterizing Risk for Cumulative Risk Assessments

In assessing environmental health risks, the risk characterization step synthesizes information gathered in evaluating exposures to stressors together with dose–response relationships, characteristics of the exposed population, and external environmental conditions. This article summarizes key steps of a cumulative risk assessment (CRA) followed by a discussion of considerations for characterizing cumulative risks. Cumulative risk characterizations differ considerably from single chemical‐ or single source‐based risk characterization. CRAs typically focus on a specific population instead of a pollutant or pollutant source and should include an evaluation of all relevant sources contributing to the exposures in the population and other factors that influence dose–response relationships. Second, CRAs may include influential environmental and population‐specific conditions, involving multiple chemical and nonchemical stressors. Third, a CRA could examine multiple health effects, reflecting joint toxicity and the potential for toxicological interactions. Fourth, the complexities often necessitate simplifying methods, including judgment‐based and semi‐quantitative indices that collapse disparate data into numerical scores. Fifth, because of the higher dimensionality and potentially large number of interactions, information needed to quantify risk is typically incomplete, necessitating an uncertainty analysis. Three approaches that could be used for characterizing risks in a CRA are presented: the multiroute hazard index, stressor grouping by exposure and toxicity, and indices for screening multiple factors and conditions. Other key roles of the risk characterization in CRAs are also described, mainly the translational aspect of including a characterization summary for lay readers (in addition to the technical analysis), and placing the results in the context of the likely risk‐based decisions.     

Probabilistic Risk Analysis and Terrorism Risk

Since the terrorist attacks of September 11, 2001, and the subsequent establishment of the U.S. Department of Homeland Security (DHS), considerable efforts have been made to estimate the risks of terrorism and the cost effectiveness of security policies to reduce these risks. DHS, industry, and the academic risk analysis communities have all invested heavily in the development of tools and approaches that can assist decisionmakers in effectively allocating limited resources across the vast array of potential investments that could mitigate risks from terrorism and other threats to the homeland. Decisionmakers demand models, analyses, and decision support that are useful for this task and based on the state of the art. Since terrorism risk analysis is new, no single method is likely to meet this challenge. In this article we explore a number of existing and potential approaches for terrorism risk analysis, focusing particularly on recent discussions regarding the applicability of probabilistic and decision analytic approaches to bioterrorism risks and the Bioterrorism Risk Assessment methodology used by the DHS and criticized by the National Academies and others.     

Risk Perception and Risk Talk: The Case of the Fukushima Daiichi Nuclear Radiation Risk

Individuals’ perceptions and their interpersonal communication about a risk event, or risk talk, can play a significant role in the formation of societal responses to the risk event. As they formulate their risk opinions and speak to others, risk information can circulate through their social networks and contribute to the construction of their risk information environment. In the present study, Japanese citizens’ risk perception and risk talk were examined in the context of the Fukushima Daiichi nuclear radiation risk. We hypothesized and found that the risk information environment and risk literacy (i.e., competencies to understand and use risk information) interact to influence their risk perception and risk talk. In particular, risk literacy tends to stabilize people's risk perceptions and their risk communications. Nevertheless, there were some subtle differences between risk perception and communication, suggesting the importance of further examination of interpersonal risk communication and its role in the societal responses to risk events.     

The Dynamics of Risk Perception: How Does Perceived Risk Respond to Risk Events?

This paper examines the relationship between perceived risk and experience. This research addresses the processes by which people learn about risk and choose among real life prospects with associated uncertainties, risks and benefits. By comparing the impact of acute risk events with that of chronic risk events on public perception of risk during and after the events, this research focuses on the learning processes that characterize what kinds of risk events alter the perception of risk. Comparing materialized hazards at existing facilities with the risks associated with potential facilities, this research addresses risk choices among real life prospects. This study uses a classic pre-post quasi-experimental design. Surveys conducted in the Spring of 1992 on perceived and acceptable risk in Odessa and La Porte, Texas were conducted prior to risk events. Respondents from that survey were re-interviewed in the Spring of 1993 after the risk events to form a panel design. This paper analyzes the affect of risk events on perceived risk and the implications of these experiences for public policy concerning technological risk. The empirical results suggest that the social processes that construct and maintain risk in the public eye are at least as important as, if not more important than, the physical and psychological dimensions of risk.     

考虑事件风险的在险价值研究

本文讨论了考虑事件风险的资产的在险价值方法,并以此对上海股票指数作了实证研究。这种方法用跳跃来描述事件风险,用跳跃-扩散过程来描述收益率过程。通过模拟退火算法来估计模型参数,利用随机模拟方法求得资产收益率的模拟分布,进而计算组合的在险价值。通过对上海指数的实证研究表明,资产的事件风险是不可忽略的,考虑事件风险的在险价值更加合理。     

Dimensions of Risk

Eight major factors of risk comparisons are presented, and the conventional reduction of the risk concept to a unidimensional format is challenged. The similarities between risk issues and other issues of the social decision process are stressed. It is concluded that risk decisions are part of the general political process, and cannot be isolated from this. Expert assessments should be presented in a way that reflects the complexity of the subject matter, instead of repressing it.     

One Agency's Use of Risk Assessment and Risk Communication1

Few organizations have the courage to evaluate their own use of risk assessment (identifying hazards and estimating their probability and magnitude) and risk communication (interacting with internal and external stakeholder groups about risks). The USDA Animal and Plant Health Inspection Service (APHIS) wants to enhance its overall risk analysis process for managing a wide range of risks to animals, plants, and human health. We gathered survey data for a baseline of APHIS professionals’ understanding and use of risk assessment and risk communication. APHIS professionals spend a surprisingly large share of their time communicating about risks. They perceive that risk estimates influence decisions, but that risk estimates should have more influence. Respondents reported little opposition to APHIS risk management decisions, and little use of channels such as USDA Extension Service for disseminating risk messages. Substantial variance across responses is explained mostly by differences in the roles of the 11 work units (now 10) within the agency. Location also contributes to the variance. Demographic variables seem less important.     

风险理论反思与领导决策风险应对

风险的不确定性和恐惧的普遍性都对传统的政府确定性行政提出了挑战,政府正面临从确定性行政向不确定性行政的转型,这对领导干部的风险决策能力提出了新的转型要求。这种转型要求主要体现在风险决策工具的选择及其不确定性分析,对风险评估责任人的确定,对风险评估行为的监管以及风险信息的引领等方面。