Discrepancies between ex ante and ex post efficiency under identical subjective probabilities

Summary. Starr (1973) showed that, if people have different subjective probabilities, ex ante and ex post efficiency conflict. Conversely, under the simple preferences that he considered, the discrepancy between ex ante and ex post efficiency disappears when subjective probabilities are identical. Here I consider identical subjective probabilities, but more general preferences. First, risk attraction is admitted. Second, I dispense with the double requirement (dubbed IZU) of additive separability and state-independence of the utility of zero-date consumption, an unrealistic requirement when modeling the investment in durable goods. I find that, under IZU, and as long as ex post preferences satisfy the natural assumption of quasiconcavity (and satisfy some technical qualifications), an ex ante efficient allocation is indeed ex post efficient, but the converse is not necessarily true under risk attraction. If, on the other hand, IZU is violated, then one can have ex ante efficient allocations that are not ex post efficient, and vice-versa, even under risk aversion. Received: June 25, 1999; revised version: March 2001     

企业风险传导及其载体研究

本文在概述风险与企业风险的基础上定义了何为企业风险传导,并对企业风险的传导路径作了归纳和分析;阐述了在企业风险的传导链和传导网络中,载体是风险传导过程中风险各要素相互联系的桥梁,也是各要素相互作用实现的有效形式;还揭示了在整个风险传导过程中,载体具有承载风险和传导风险的作用,同时,风险源、驱动力以及风险载体之间相互作用形成的耦合效应也使载体在企业风险传导链中具有“放大镜”的效应;并从企业风险传导的角度探讨了如何防范和控制企业风险。     

Keynes, uncertainty and interest rates

Uncertainty plays an important role in The General Theory, particularlyin the theory of interest rates. Keynes did not provide a theoryof uncertainty, but he did make some enlightening remarks aboutthe direction he thought such a theory should take. I arguethat some modern innovations in the theory of probability allowus to build a theory which captures these Keynesian insights.If this is the right theory, however, uncertainty cannot carryits weight in Keynes's arguments. This does not mean that theconclusions of these arguments are necessarily mistaken; intheir best formulation they may succeed with merely an appealto risk.     

IT集成项目的风险评价与控制

本文就 IT集成项目的风险问题进行了系统研究和探讨 ,其内容包括 IT集成项目的特点、风险的产生与特征、预测和评价、防范和控制等。     

新兴加转轨条件下中国证券公司的风险成因及监控

证券业是一个高风险行业 ,防范和化解风险是证券公司和监管机构的永恒主题。随着我国证券市场的蓬勃发展和逐渐规范 ,证券公司风险监控已经成为一项长期的重大任务。中国目前正处于新兴加转轨过程中 ,证券公司主要面临哪些风险 ?是如何形成的 ?在特定约束条件下怎样提高监控效率 ?围绕这些问题 ,本文首先对中国证券公司的风险及其成因进行分析 ,接着从实践的角度指出风险监控的现实约束 ,最后提出内外部风险监控协调与平衡的基本架构。     

基于CAPM的中国股市羊群行为研究——兼与宋军、吴冲锋先生商榷

本文首先对宋军和吴冲锋的《基于股价分散度的金融市场羊群行为研究》一文进行了分析 ,指出其在分析方法和论证逻辑两方面存在的问题。随后 ,本文以资本资产定价模型 (CAPM)为基础 ,建立了一个更为灵敏的羊群行为检验模型 ,并据此对我国股市进行了实证检验。研究结果表明 :在政策干预频繁和信息不对称严重的市场环境下 ,我国股市存在一定程度的羊群行为 ,并导致系统风险在总风险中占有较大比例     

税务征收体制下的社会保险费征管制度建设研究

我国社会保险费征管体制改革正在不断深入。当前,社会保险费征管仍存在制度设计有待完善、法律依据不够清晰的问题。本文基于税收征管视角,对社会保险费征管制度进行了重新审视,在全面梳理了制约社会保险费征管制度完善的限制性因素的基础上,从科学设置社会保险费征管前置程序、全面构建社会保险费征管的保障程序等多个方面,对将社会保险费征管融入税收征管流程的可行性进行了分析和探讨,以期为我国社会保险费征管制度的完善提供参考。     

Risk-taking incentives of executive stock options and the asset substitution problem

Various theoretical models show that managerial compensation schemes can reduce the distortionary effects of financial leverage. There is mixed evidence as to whether highly levered firms offer less stock‐based compensation, a common prediction of such models. Both the theoretical and empirical research, however, have overlooked the leverage provided by executive stock options. In principle, adjusting the exercise prices of executive stock options can mitigate the risk incentive effects of financial leverage. We show that the near‐universal practice of setting option exercise prices near the prevailing stock price at the date of grant effectively undoes most of the effects of financial leverage. In a large cross‐sectional sample of Canadian option‐granting firms, we find evidence that executives' incentives to take equity risk are negatively rather than positively related to the leverage of their employers.     

存在风险条件下的资本市场投资预期收益模型研究

风险是指预期收益的不确定性,是指在将来一段时间内遭受损失的可能性.进行资本市场投资,必然存在风险.资本市场投资风险就是投资预期结果(预期收益损失)的不确定性,有投资风险,就会有投资者对其进行的预期.本文建立了存在风险条件下的资本市场投资预期收益模型,并由此得出了不同投资者的预期收益--风险偏好的不同投资选择.     

动态资本资产定价理论评述

本文主要讨论了动态资产定价理论的产生和发展.默顿和布里登使用贝尔曼开创的动态规划方法和伊藤随机分析技术,重新考察在由随机过程驱动的不确定环境下,个人如何连续地做出消费/投资决策,使得终身效用最大化.无须单期框架中的严格假定,他们也获得了连续时间跨期资源配置的一般均衡模型--时际资产定价模型(ICAPM)以及消费资产定价模型(CCAPM).这些工作开启了连续时间金融方法论的新时代.