我国医疗保健行业股指收益率波动特征与杠杆效应

本文运用SWARCH模型分析了我国医疗保健板块收益率的波动,并将医疗保健板块收益率与上证综指、深证成指收益率的SWARCH模型的估计结果进行比较,得出以下结论:医疗保健指数收益率序列呈现出低、中、高三种波动状态,样本区间主要分布于中波动状态,低波动状态的平均持续期最长、中波动状态的平均持续期居中、高波动状态的平均持续期最短,医疗保健指数收益率波动杠杆效应显著;我国股市医疗保健板块收益率波动状态之间的差异高于沪深综指波动状态的差异,医疗保健指数收益率与沪深综指收益率区制转移趋同,但存在着细微差异;医疗保健指数收益率各区制间转移相对频繁,每种波动状态的平均持续期较短,股市医疗保健板块收益率对新信息的反应更为敏感。     

Error analysis of finite difference and Markov chain approximations for option pricing

Mijatovi? and Pistorius proposed an efficient Markov chain approximation method for pricing European and barrier options in general one‐dimensional Markovian models. However, sharp convergence rates of this method for realistic financial payoffs, which are nonsmooth, are rarely available. In this paper, we solve this problem for general one‐dimensional diffusion models, which play a fundamental role in financial applications. For such models, the Markov chain approximation method is equivalent to the method of lines using the central difference. Our analysis is based on the spectral representation of the exact solution and the approximate solution. By establishing the convergence rate for the eigenvalues and the eigenfunctions, we obtain sharp convergence rates for the transition density and the price of options with nonsmooth payoffs. In particular, we show that for call‐/put‐type payoffs, convergence is second order, while for digital‐type payoffs, convergence is generally only first order. Furthermore, we provide theoretical justification for two well‐known smoothing techniques that can restore second‐order convergence for digital‐type payoffs and explain oscillations observed in the convergence for options with nonsmooth payoffs. As an extension, we also establish sharp convergence rates for European options for a rich class of Markovian jump models constructed from diffusions via subordination. The theoretical estimates are confirmed using numerical examples.     

EMPLOYMENT STABILIZATION INSIDE FIRMS: AN EMPIRICAL INVESTIGATION OF WORKER COOPERATIVES

There is evidence that worker cooperatives provide a greater stabilization of employment compared to capital‐managed firms. While the reasons of this behaviour can be ascribed to their property and governance structure, less is known of the tools to put it into practice. I discuss two possible ways to guarantee employment insurance: by letting wages fluctuate, or by accumulating reinvested profits into an income stabilizing fund that copes with downturns without firing and without reducing wages. In this second case, I find out that asset locks play a wage smoothing role. This may explain the large share of profits that are reinvested in this indivisible and not appropriable fund. I provide evidence for this mechanism by means of original data at the firm level and of first‐hand collected survey data at the individual level on risk perception in a sample of Italian cooperatives.     

Statistical inference on restricted partial linear regression models with partial distortion measurement errors

We consider the estimation and hypothesis testing problems for the partial linear regression models when some variables are distorted with errors by some unknown functions of commonly observable confounding variable. The proposed estimation procedure is designed to accommodate undistorted as well as distorted variables. To test a hypothesis on the parametric components, a restricted least squares estimator is proposed under the null hypothesis. Asymptotic properties for the estimators are established. A test statistic based on the difference between the residual sums of squares under the null and alternative hypotheses is proposed, and we also obtain the asymptotic properties of the test statistic. A wild bootstrap procedure is proposed to calculate critical values. Simulation studies are conducted to demonstrate the performance of the proposed procedure, and a real example is analyzed for an illustration.     

非寿险公司赔款准备金与盈余管理——中国市场的经验分析

利用我国非寿险公司2001~2007年的财务数据,采用分位数回归方法探讨非寿险公司赔款准备金调整的动机,并比较非寿险业务准备金评估方法改变前后公司实现盈余管理动机的差异。研究发现,非寿险公司存在实现盈余管理的现象,相比规避递延税收的目的而言,管理层故意调整公司当年赔款准备金数字进行盈余平滑的动机更为显著。当公司当期盈余表现差于前一期时,管理者倾向于低估当期赔款准备金提升账面盈余;若当期盈余表现优于前一期时,则高估准备金平滑盈余。在当年承保业务不佳,赔付率较高时,非寿险公司具有低估准备金掩饰承保质量的动机。2005年非寿险业务赔款准备金评估方法的改变,显著增强了非寿险公司利用赔款准备金进行盈余管理的动机。     

基于遥感技术的耕地复种指数研究进展

复种是我国重要的农作制度之一,对于提高我国耕地综合生产能力和确保国家粮食安全具有重要作用。该文在介绍复种指数基本概念和研究方法的基础上,对基于遥感技术的耕地复种指数研究进展进行了评述,尤其对时序植被指数平滑方法和复种指数的判别方法等两个关键技术进行了详细阐述。该文提出了遥感技术和地面观测的结合将是未来耕地复种指数遥感监测的发展趋势之一。如何进行遥感数据平滑最优化处理,以及获取高时空分辨率遥感数据及规范准确的地面观测数据将是需要重点解决的关键问题。     

中国改革开放以来财政政策平滑经济波动的能力——基于传统IS-LM模型的实证分析

文章通过借助传统IS-LM模型和比较静态分析方法对中国改革开放以来财政政策平滑经济波动的能力进行了实证分析,得出:(1)财政政策对经济波动的整体平滑能力较低,平均只有6.35%,财政政策的平滑能力在经济波动的不同状态之间存在明显差异;(2)财政政策工具之间的平滑能力存在较大差异,其中财政购买性支出能平滑掉经济初始冲击的11.48%,而财政转移性支出和收入政策整体上反而使经济波动上升近3%;(3)内生性检验表明,中国只有相机性支出政策与经济波动之间存在显著的双向因果关系,不仅如此,相机性支出政策的内外时滞都较短。文章结论的政策含义是,提高中国财政政策稳定效果的关键在于提高政策工具的有效性与相互之间的协同效应,不仅如此,对经济高涨时期政府财政行为进行有效约束也至关重要。     

供应链集中度、产权差异与盈余透明度

随着供应链集中度的不断提高,企业管理层实施盈余管理的动机逐渐增强,使盈余信息的真实性和全面性降低,最终导致盈余透明度降低.本文选用供应商集中度和客户集中度两个解释变量作为供应链集中度的替代变量,以盈余激进度、盈余平滑度和透明度综合指数3个指标衡量盈余透明度,利用沪深A股制造业上市公司2010-2017年6104个供应商集中度的数据和7654个客户集中度的数据进行实证检验,研究供应链集中度提高影响企业盈余透明度的作用机制和影响程度.结果 发现:①就供应链整体来看,供应链集中度较高的企业虚增盈余和平滑盈余的动机较强,从而对盈余透明度产生显著的负面影响,且其虚增盈余的动机要高于平滑盈余的动机;②具体来看,供应商集中度较高的企业虚增盈余和平滑盈余的动机较强,而客户集中度较高的企业则更多的采用虚增盈余进行盈余管理;③在区分产权性质后,前两条结论仍然成立,但在非国有企业中表现得更为显著.此外还发现企业的盈余透明度并不受其规模大小的影响,而较高的经营风险则会增强管理层虚增盈余和平滑盈余的动机使企业的盈余透明度降低.     

新会计准则下我国上市公司债务重组动因研究——基于A股上市公司2007年数据

在我国2007年实施新的《企业会计准则——债务重组》的背景下,结合盈余管理的理论,对我国A股上市公司债务重组动因进行的实证分析发现,财务状况改善、扭亏对上市公司债务重组幅度有显著影响,平滑利润对上市公司债务重组幅度影响不显著。     

Intertemporal production and intertemporal substitution in output supply and input demand

This article presents an intertemporal model of production with multiple inputs to investigate substitution opportunities facing firms over time. The firm’s intertemporal profit maximization problem is characterized with the familiar cost function, and various intertemporal substitution elasticities are delineated for output supply and input demand. The absence of intertemporal substitution in production can imply production smoothing, and allowance for intertemporal substitution in labour demand reinforces the prediction of the real business cycle model. For aggregate US manufacturing, we find substantial substitution in output supply and labour demand over time due to intertemporal changes in output price and wage rates.