基于Copula函数的ETF流动性风险与市场风险相依性分析

以截至 2009 年 12 月 18 日在上海证券交易所和深圳证券交易所公开发行的易方达深证 100ETF、华夏中小板 ETF、华夏上证 50ETF、华安上证 180ETF、华泰柏瑞上证红利ETF共5只交易型开放式指数基金为研究对象,度量指数基金的流动性风险和市场风险,并以GARCH (1,1) 对风险的边缘分布进行建模,同时应用Copula函数的相关系数分别对不同指数基金的流动性风险和市场风险的相依性进行度量.实证研究表明,指数基金的流动性风险和市场风险都呈现出波动聚集的特性,华安上证 180ETF 的流动性风险和5只ETF的市场风险均具有尖峰厚尾的分布特性.在证券市场牛市时,华夏上证 50ETF 和华安上证 180ETF 的流动性风险与市场风险呈现负相依的特性,而华泰柏瑞上证红利ETF、易方达深证 100ETF 和华夏中小板ETF的流动性风险与市场风险呈现正相依的特性;在证券市场熊市时,指数基金的流动性风险与市场风险均呈现正相依的特性.     

我国证券市场风险的法律防范

我国证券市场虽然经过十多年的发展有了长足的进步,但是由于起步晚和我国的特殊原因仍然还不成熟。这就导致我国证券市场的风险比发达国家证券市场的风险更大、也更特殊。面对这种情况,我们应该致力于主要用法律的手段对证券市场的风险进行防范,完善我国的证券立法,加强证券市场主体的监督,同时建立一个完善的信用机制,充分发挥行业自治的作用,最大程度的防范风险。     

中国证券市场流动性风险探析

证券市场流动性的好坏与否,直接关系到证券市场的稳定、对增强投资者的信心起着至关重要的作用。本文简要阐述了影响市场流动性的因素并且做了简要的分析,最后提出了一些建议,旨在降低中国证券市场的流动性风险,提高我国证券市场的配置效率。     

流动性风险、投资者流动性需求与资产定价

依据证券市场的交易特点把投资者面临的市场流动性风险分解为外生和内生流动性风险,并引入流动性需求状态变量随机化了的投资者对证券的持有期限,得出基于流动性风险调整的资产定价模型.模型能够解释实证研究发现的投资者对流动性风险中不可分散的系统性部分要求相应的风险补偿现象.而且模型揭示出,流动性水平和市场流动性风险的补偿要求是投资者的流动性需求紧张程度的增函数,解释了流动性风险溢价的时变性现象.     

基于VaR模型的开放式基金流动性风险研究

本文从流动性的基本定义出发,根据我国证券市场的特征,设计了一个流动性度量指标,并将该指标纳入VaR风险度量体系.并进行了实证研究,分析了基金流动性风险及其实际意义.     

风险价值的计算方法及其在证券风险管理中的应用

在综述风险价值的定义及多种计算方法后,重点讨论了历史模拟法,并对我国证券市场部分数据进行了实证分析,论证了风险价值模型在我国证券市场风险管理中的可行性.     

溢出效应与门限特征:金融开放条件下国际证券市场风险对中国市场冲击机理

伴随着全球经济一体化和我国金融市场逐渐开放,国际证券市场风险对我国市场冲击愈来愈明显。本文应用单变量MSVAR模型和二元向量SWARCH模型实证分析了来自海外市场风险冲击的机理。采用美国S&P500指数、英国FTSE350指数、日本Nikkei225指数和中国上证综指周收益率数据,按照市场波动状态划分为"高"、"低"两个风险积聚状态,不同风险积聚水平下状态相关系数估计结果存在的显著差异,表明国际证券市场对我国市场存在风险溢出效应,且具有明显的"门限特征",高市场风险积聚状态下海外市场与沪市间正相关性,市场的整体风险性强;低市场风险积聚状态下,市场间负相关,市场整体表现出较低的系统风险特征。因此,国际证券市场对我国市场风险溢出传导机理依赖于市场的风险积聚状态。     

双侧系统性风险及其在中国股市的实证研究

基于代表性投资者下跌风险规避和上升风险喜好推导出双侧风险偏好资产定价模型,并基于该模型实现了双侧系统性风险的分离.运用中国A股市场1996年～2003年的收益数据进行实证研究表明,双侧系统性风险的绝对值在研究样本区间初期较高,随后逐年下降,说明中国证券市场日趋规范,也与1996年以后实行的股市涨跌幅设限等政策有关;与外在重大信息冲击影响对应,双侧系统性风险的相对比例在研究样本期间内表现为一波三折.     

存在老鼠仓时的投资、消费与风险溢价

首先,对存在老鼠仓情况下市场各方投资、消费策略进行建模.做仓机构投资者偏好向老鼠仓消费的转移将导致其增加投资并减少消费;同时老鼠仓引发的资产价格变动将影响投资者对于资产未来收益的预期,导致投资者之间对于资产收益率的信念产生不一致.这两个方面的共同作用将提高均衡时市场的风险溢价.最后,利用我国证券市场相关数据对模型进行实证分析,结果较好地规避了"股权溢价之迷".     

基于VaR模型的开放式基金流动性风险研究

本文从流动性的基本定义出发,根据我国证券市场的特征,设计了一个流动性度量指标,并将该指标纳入VaR风险度量体系。并进行了实证研究,分析了基金流动性风险及其实际意义。     

上市公司融资偏好的内部治理机制研究

面对弱效率的资本市场,如何有效地解决国内上市公司在融资选择时对股权融资的过度偏好成为实务和理论界关注的一个重要问题。本文认为除了现行研究所提出的完善资本市场的规范性和有效性,加强上市公司的外部调控和管制以外,还有一个很重要的方面就是从微观的公司治理角度来分析上市公司的融资行为。在这一思路的基础上,本文利用一个多任务委托代理模型来解释影响企业融资方式的内部因素,并从公司治理结构的角度来提出完善融资激励和约束机制的要素。     

Cyber Security Risk Management: Public Policy Implications of Correlated Risk,Imperfect Ability to Prove Loss,and Observability of Self‐Protection

The correlated nature of security breach risks, the imperfect ability to prove loss from a breach to an insurer, and the inability of insurers and external agents to observe firms’ self‐protection efforts have posed significant challenges to cyber security risk management. Our analysis finds that a firm invests less than the social optimal levels in self‐protection and in insurance when risks are correlated and the ability to prove loss is imperfect. We find that the appropriate social intervention policy to induce a firm to invest at socially optimal levels depends on whether insurers can verify a firm's self‐protection levels. If self‐protection of a firm is observable to an insurer so that it can design a contract that is contingent on the self‐protection level, then self‐protection and insurance behave as complements. In this case, a social planner can induce a firm to choose the socially optimal self‐protection and insurance levels by offering a subsidy on self‐protection. We also find that providing a subsidy on insurance does not provide a similar inducement to a firm. If self‐protection of a firm is not observable to an insurer, then self‐protection and insurance behave as substitutes. In this case, a social planner should tax the insurance premium to achieve socially optimal results. The results of our analysis hold regardless of whether the insurance market is perfectly competitive or not, implying that solely reforming the currently imperfect insurance market is insufficient to achieve the efficient outcome in cyber security risk management.     

Sourcing Information Security Operations: The Role of Risk Interdependency and Competitive Externality in Outsourcing Decisions

Firms are increasingly outsourcing information security operations to managed security service providers (MSSPs). Cost reduction and quality (security) improvement are often mentioned as motives for outsourcing information security, and these are also the frequently cited reasons for outsourcing traditional information technology (IT) functions, such as software development and maintenance. In this study, we present a different explanation—one based on interdependent risks and competitive externalities associated with IT security—for firms' decisions to outsource security. We show that in the absence of competitive externalities and interdependent risks, a firm will outsource security if and only if the MSSP offers a quality advantage over in‐house operations, which is consistent with the conventional explanation for security outsourcing. However, when security risks are interdependent and breaches impose competitive externalities, although firms still have stronger incentive to outsource security if the MSSP offers a higher quality in terms of preventing breaches than in‐house management, a quality advantage of MSSP over in‐house management is neither a prerequisite for a firm to outsource security nor a guarantee that a firm will. In addition to MSSP quality, the type of externality (positive or negative), the degree of externality, whether outsourcing increases or decreases risk interdependency, and the breach characteristics determine firms' sourcing decisions. When security breaches impose a positive externality, the incentive to outsource is enhanced if the MSSP decreases the risk interdependency and diminished if the MSSP increases this interdependency. A negative externality has the opposite effect on firms' incentives to outsource. A high demand spillover to a competitor, together with a high loss in industry demand because of a security breach, enhances these incentives to outsource security operations when the externality is negative. Finally, we extend our base model in several dimensions and show that our main results regarding the impact of interdependent risks and competitive externalities on sourcing decisions are robust and generalizable to different specifications.     

Security Investment in Contagious Networks

Security of the systems is normally interdependent in such a way that security risks of one part affect other parts and threats spread through the vulnerable links in the network. So, the risks of the systems can be mitigated through investments in the security of interconnecting links. This article takes an innovative look at the problem of security investment of nodes on their vulnerable links in a given contagious network as a game‐theoretic model that can be applied to a variety of applications including information systems. In the proposed game model, each node computes its corresponding risk based on the value of its assets, vulnerabilities, and threats to determine the optimum level of security investments on its external links respecting its limited budget. Furthermore, direct and indirect nonlinear influences of a node's security investment on the risks of other nodes are considered. The existence and uniqueness of the game's Nash equilibrium in the proposed game are also proved. Further analysis of the model in a practical case revealed that taking advantage of the investment effects of other players, perfectly rational players (i.e., those who use the utility function of the proposed game model) make more cost‐effective decisions than selfish nonrational or semirational players.     

中国证券投资基金的羊群行为分析

根据投资基金中报和年报中的投资明细数据,采用文献[1]和文献[2]的检验方法,从不同角度实证检验了中国投资基金的羊群效应,发现中国投资基金的羊群效应高于美国互助基金的羊群效应,中国投资基金并未表现出对大盘股、小盘股、新股以及信息技术行业样本股票的特别偏好。投资基金的交易以买为主。投资基金的投资重心有从小盘股向大盘股转变的趋势,这将有利于整个证券市场的稳定。投资基金的交易行为与股市走势密切相关。     

煤炭资源产权、产品市场协调机制与供应安全

明确了研究煤炭资源产权、产品市场协调与供应安全的背景和意义,辨识了煤炭资源供应安全的概念、内涵及表现形式。提出了实现煤炭资源供应安全的途径,即完善煤炭资源产权和产品市场之间的协调。然后,从加强煤炭资源产品市场建设、推进煤炭资源产权市场建设、建立国家煤炭资源战略储备机制,以及引导和控制煤炭进出口、实施"走出去"战略等方面,对保障煤炭资源供应安全的措施进行了讨论。     

做市商制度下证券价格的形成机制分析

证券价格的形成要受到交易机制的约束,也会受到投资者的风险偏好、信念以及对信息获知程度的影响.文章将把这两方面因素结合起来考虑,把信息不对称引入模型,对做市商市场的证券价格形成机制进行了均衡分析.结果表明,一方面,在存在做市商的证券市场,投资者根据自己的风险偏好、信念和获知信息进行交易以使预期效用最大化,交易指令的下达与执行传达了证券清算价值的信息.做市商通过对指令信息的观察而进行双向报价,为市场提供了流动性;另一方面,证券市场的有序运行不仅跟交易机制有关,还受到投资者的风险偏好、信念以及信息上的差异等的影响,这也是决定证券价格的关键因素.     

Global Maize Trade and Food Security: Implications from a Social Network Model

In this study, we developed a social network model of the global trade of maize: one of the most important food, feed, and industrial crops worldwide, and critical to food security. We used this model to analyze patterns of maize trade among nations, and to determine where vulnerabilities in food security might arise if maize availability was decreased due to factors such as diversion to nonfood uses, climatic factors, or plant diseases. Using data on imports and exports from the U.N. Commodity Trade Statistics Database for each year from 2000 to 2009 inclusive, we summarized statistics on volumes of maize trade between pairs of nations for 217 nations. There is evidence of market segregation among clusters of nations; with three prominent clusters representing Europe, Brazil and Argentina, and the United States. The United States is by far the largest exporter of maize worldwide, whereas Japan and the Republic of Korea are the largest maize importers. In particular, the star‐shaped cluster of the network that represents U.S. maize trade to other nations indicates the potential for food security risks because of the lack of trade these other nations conduct with other maize exporters. If a scenario arose in which U.S. maize could not be exported in as large quantities, maize supplies in many nations could be jeopardized. We discuss this in the context of recent maize ethanol production and its attendant impacts on food prices elsewhere worldwide.     

强制性约束下企业信息安全投资与网络保险的最优决策分析

研究了强制性约束下企业信息安全投资和网络保险的最优决策问题,对比了可观测企业损失和不可观测企业损失两种情形下基于破产概率约束的最优安全投资和网络保险保费厘定。研究结果表明：在可观测损失和公平保费情况下,当最大化单个企业的期望效用时,存在最优安全投资额,并且政府补贴和强制性约束都可以激励企业增加安全投资;但是当最大化所有企业效用时,只有强制性约束才能增加企业安全投资使得总效用最大化,并且企业的最优安全投资与损失的可观测程度无关。在不可观测损失情况下,当最大化单个企业期望效用时,企业的安全投资增大,而最大化所有企业效用时,存在正网络外部性,即任何企业均不敢轻易的减少安全投资,即使同在一个网络中的其他企业减少了安全投资。此外,在破产概率约束下,随着保费的增加,当损失可观测时,企业的安全投资也增加,但期望效用减少了;而当损失不可观测时,企业的安全投资和期望效用均减少。本文所得结论对政府设定强制性标准,以及企业利用安全投资和网络保险进行信息安全风险控制具有较好的参考价值。     

一种新型商品定价模型与价格安全指数评估体系

本文提出了偏态分布与偏态过程的概念及其数学表达式,该分布与过程适用于对各种商品价格变化的分析和描述;给出了反映商品内在价格、市场价格、内在风险和市场风险基本关系的数量模型,该模型可用于分析和实现包括现货、股票、期货、期权在内的各类商品、衍生商品的逻辑化市场定价及市场风险度量;设计了针对成本价格、市场价格和综合价格的安全指数,可对社会、经济、金融、科技、教育等各行业的商品价格及发展状况进行安全性测算和评估。