股票分析师的羊群行为对公司股价同步性的影响分析

股价"同涨同跌"是我国股票市场的一种重要现象。多股集体"暴跌"会给公司和投资者造成严重的损失,因而股价同步性的问题受到监管者和学术界的广泛关注。本文以2010-2017年股票分析师对上市公司做出的预测为主要研究对象,验证了股票分析师的羊群行为与公司股价同步性间的关系,讨论了机构投资者和市场情绪的作用机制。实证结果表明我国股票分析师的羊群行为是"非信息驱动"的真羊群行为,这种行为降低了市场上的特质信息含量,从而增加了公司的股价同步性。上述关系在熊市中更为显著,并且分析师与机构投资者之间的利益冲突会加剧其羊群行为对股价同步性的影响。本文的研究对理解如何降低股价崩盘风险、提高我国股票市场的信息传递效率具有十分重要的理论和实践意义。     

分析师文本语调会影响股价同步性吗?——基于利益相关者行为的中介效应检验

文章考察了分析师研究报告的文本语调对股价同步性的影响与作用机制.首先爬取2006年至2018年中国A股上市公司377644份分析师研究报告,随机选出10434句文本并人工分为积极、中性、消极三类形成语料库,以此训练11种机器学习方法并比较各方法的预测准确性,最终选择朴素贝叶斯方法估计出分析师研究报告的文本语调.实证分析发现,分析师积极的文本语调显著降低了所追踪公司的股价同步性.这一结果与已有多数研究结论不同,但在做空机制欠发达的中国资本市场,个体选择性知觉理论为此提供了很好的解释.进一步地,中介效应检验结果表明,分析师积极的文本语调通过激励公司发布更多公告、引导机构投资者买入和吸引其他分析师发布研究报告,显著降低了股价同步性.该研究对于投资者关注研报语调指标、上市公司加强信息披露、政府部门完善资本市场制度均具有重要启示.     

新闻媒体报道与资本市场定价效率——基于股价同步性的分析

基于我国证券市场股票价格"同涨同跌"现象,本文利用2007~2012年上市公司数据,考察了新闻媒体报道对资本市场定价效率的影响。我们研究发现,媒体报道与股价同步性显著负相关,即随着媒体报道的增多,更多公司层面信息融入股票价格,股价同步性降低。进一步的分析显示,对于分析师跟踪人数越多及机构投资者持股比例越高的公司,股价同步性受媒体报道影响而下降得更明显;相反,对于业务复杂公司,媒体报道对股价同步性的减缓作用减弱。最后,我们的研究表明,媒体报道对公司股价同步性的影响主要通过负面报道产生,而且,网络新闻媒体报道也有助于公司股价同步性的降低。     

信息性交易概率与股价同步性

财务学研究将资本资产定价模型的统计量R2作为股价同步性的度量指标,而对R2代表的经济含义学者们持有信息论和噪声论两种对立观点。在文献回顾的基础上,深入分析中国股价同步性所代表的经济含义以及知情交易对股价同步性的影响,并以深市2003年至2004年在主板交易的上市公司为研究对象,采用EKOP模型估计股票的信息性交易概率,将其作为知情交易的直接度量,构建线性回归模型,对中国信息性交易概率与股价同步性的关系进行实证检验。研究结果表明,信息性交易概率与股价同步性之间呈高度负向相关,即知情交易通过增加股价中的信息含量降低股价同步性。由于市场层面的信息与公司特质信息对股价同步性的影响不同,进一步将信息性交易概率分解为市场信息性交易概率和个股信息性交易概率,分别纳入回归模型中进行检验。结果显示,个股信息性交易概率对股价同步性有负向影响,市场信息性交易概率与股价同步性有正相关关系。上述研究发现为R2股价信息含量的解释提供了有利的实证支持。     

股价波动非同步性——信息还是噪音?

股价波动非同步性代表信息还是噪音是现代金融学的热点问题.本文首先构建公司层面信息指标和噪音指标,然后利用非平衡面板数据回归发现中国上市公司股价非同步性与信息(或噪音)之间存在U型关系.最后通过盈余公告效应和股价信息含量检验表明股价非同步性整体表现为噪音,即高非同步性公司具有较强的盈余公告后漂移以及股价较少反应当期和未来盈余信息.与信息解释不同,本文认为不能简单地将股价非同步性视为公司层面信息的度量.     

高铁开通与股价同步性:信息效应还是治理效应?北大核心CSCDCSSCI

经济主体之间的地理距离是影响信息传递效率的重要因素,交通基础设施建设可以通过重塑空间结构来减少由于地理距离造成的信息损失.本文利用中国高铁开通这一准自然实验,检验了高铁开通影响股价同步性可能存在的信息效应和治理效应.研究发现,高铁开通显著降低了沿线企业的股价同步性,采用安慰剂检验和工具变量法控制内生性问题后该结论依然稳健;作用机理研究表明,高铁开通主要通过信息效应而非治理效应来降低股价同步性;异质性分析发现,在初始交通资源匮乏和信息基础设施薄弱的地区,高铁开通对股价同步性的影响更为显著.本文为新经济地理学和资本市场会计与财务领域的交叉研究提供了有益启示,证实了交通基础设施建设在提升资本市场信息效率方面有着积极作用,为在“一带一路”建设框架下实现区域资本市场的互联互通提供参考.     

高铁开通与股价同步性：信息效应还是治理效应?

经济主体之间的地理距离是影响信息传递效率的重要因素，交通基础设施建设可以通过重塑空间结构来减少由于地理距离造成的信息损失.本文利用中国高铁开通这一准自然实验，检验了高铁开通影响股价同步性可能存在的信息效应和治理效应.研究发现，高铁开通显著降低了沿线企业的股价同步性，采用安慰剂检验和工具变量法控制内生性问题后该结论依然稳健；作用机理研究表明，高铁开通主要通过信息效应而非治理效应来降低股价同步性；异质性分析发现，在初始交通资源匮乏和信息基础设施薄弱的地区，高铁开通对股价同步性的影响更为显著.本文为新经济地理学和资本市场会计与财务领域的交叉研究提供了有益启示，证实了交通基础设施建设在提升资本市场信息效率方面有着积极作用，为在“一带一路”建设框架下实现区域资本市场的互联互通提供参考.     

R2与股价中的信息含量度量

基于新古典金融经济学的分析框架,在全面分析信息、噪声、股价波动以及波动同步性(R2)相互关系的基础上,从理论角度提出了股价中信息含量与R2之间可能存在倒U字型关系的假说;将机构持股比例作为股价中信息含量的代理变量,并利用我国A股市场2004年度市场交易数据进行了标准的计量分析,实证结果证实了上述假说.从而表明:在我国A股市场上进行公司层面的分析时,如果用R2直接作为股价中信息含量的度量,可能会混淆信息与噪声对个股股价波动的影响,因为较小的R2既可能是由资本化进了更多的个股信息所引起的,也可能源于更大的噪声对个股股价所产生的影响.     

R~2与股价中的信息含量度量

基于新古典金融经济学的分析框架,在全面分析信息、噪声、股价波动以及波动同步性(R2)相互关系的基础上,从理论角度提出了股价中信息含量与R2之间可能存在倒U字型关系的假说;将机构持股比例作为股价中信息含量的代理变量,并利用我国A股市场2004年度市场交易数据进行了标准的计量分析,实证结果证实了上述假说.从而表明:在我国A股市场上进行公司层面的分析时,如果用R2直接作为股价中信息含量的度量,可能会混淆信息与噪声对个股股价波动的影响,因为较小的R2既可能是由资本化进了更多的个股信息所引起的,也可能源于更大的噪声对个股股价所产生的影响.     

监管型小股东对股价同步性的影响研究

基于2016年2月中证中小投资者服务中心(简称投服中心)持股行权试点的研究场景,采用双重差分法考察投服中心对公司股价同步性的影响。研究发现：作为监管型小股东,投服中心持股行权降低了公司的股价同步性。进一步地,投服中心对股价同步性的影响在分析师关注度较低、媒体报道较少时更显著。机制检验显示,投服中心成立后上市公司的信息披露质量提高,管理层业绩预告质量改善,产生了信息效应;投服中心行权引起媒体和监管部门的关注,可减少大股东的利益侵占行为,提高中小股东参与股东大会的积极性,发挥出治理效应。     

Power,authority and legitimacy

Management, human resources, organization, control, leadership, etc., all seem to be just so many euphemisms for power, and this suggests a discourse of management and organization that calls things by their proper name. This paper on the contrary stresses the need to resolve the concept of ‘power’ itself into more differentiated notions, and proposes that clarification may be derived from distinctions once explicit in the vocabulary of Classical antiquity, but lost in modern European languages. It argues that nothing but confusion in thinking about organizations, management and legitimation can result from the failure to recognize that the phenomena this vocabulary identifies and distinguishes are irreducibly different.     

Defining Spirituality of Work

There is a current surge of writings on spirituality and related topics. For instance, Woodward (1997) has pointed out that since Thomas Moore's publication of Care of the Soul in 1994 there have been nearly 800books published with the word soul in the title. These run all the way from Chicken Soup for theWoman's Soul (Canfield et al., 1996) to A Guide to Liberating YourSoul (Barrett, 1995). Spirituality of work is a big part of this surge. Definitionsof spirituality of work seem to vary widely. Bowman (1998, p. 8) in his `reviewof the phenomenon of spirituality of work' found `Definitions of the term spirituality in the context of the Spirituality of Work troublesome and particularly subjective. Many writers do not even attempt definitions.' The purpose of this article is to review the concept of spirituality of work in its historical and current use and to propose a comprehensive definition.     

WebStress: a web interface to explore a multidatabase bibliographic corpus on occupational stress

A bibliographic study on a multidisciplinary subject, such as occupational stress, requires a multidatabase query facility. Given this, we searched eight databases belonging to different fields (medicine, psychology, etc.) and from different countries. Thus, more than 26000 references on occupational stress were gathered. A bibliographic corpus of this sort is unusable because of the heterogeneous format of the records and the number of duplicate entries. Considering the limitations of commercial programs, we have developed a system, called WebStress, for reformatting the data and removing duplicates. The huge number of references and the research needs of updating and searching have necessitated the addition of several other functions to WebStress. Therefore WebStress comprises a web interface that makes it possible to search the corpus with advanced features (using clustering, a specialized thesaurus on stress and Boolean queries). In addition to the usual bibliographic queries on a specific database such as Medline, WebStress provides bibliometric analysis of the corpus, which might contribute to a detailed analysis on occupational stress in order to highlight the networks of researchers and to find the main topics studied in this area. WebStress is not yet available to researchers in general. It is being further developed, and also permission needs to be obtained from the eight commercial bibliographic databases that it consults.     

A new lease for life? The return of vitalism in management and organization studies

This paper starts from a growing interest in the concept of concern, lived experience or “inhabiting” as part of the so-called “affective turn”. My main argument is that the notion of concern cannot be thought or understood without the concept of life. The concept of life, however, is somewhat of a taboo topic in the social sciences. I hold, nevertheless, that in order to reflect on their assumptions and to define concern for their own studies, scholars need to think about life and make a choice regarding the various approaches that can be taken. I therefore present and compare four vitalist approaches: romanticism and Lebensphilosophie, vitalism as ethos and pathos, neuroecosociality as well as vitalism as becoming.     

Effects of the implementation of information technology on employees' strain and job satisfaction: a context-dependent approach

The effects on staff of the implementation of new office information technology were investigated in ten companies in Vienna using a longitudinal design. Strain and satisfaction of 331 employees (implementation sample: n = 212; control sample: n = 119) were measured at five points in time over a period of 22 months. The study is based on a context-dependent approach. Personal factors (individual differences, external load) were assessed by questionnaires, and situational factors (job design, implementation content and implementation context) by objective measures. The impact of these factors on employees' strain responses was tested using structural equation modelling (SEM). While the implementation of new technology as such made no significant contribution to the explanation of strain variables, a reasonable model fit was achieved when implementation characteristics were taken into account. The data suggest that negative effects of implementations must be expected if (1) adaptational demands do not include the enhancement of employee qualifications, (2) character-based user interfaces are not replaced, and (3) employees have few or no opportunities to participate in the implementation process.     

Consequences of work-family conflict on employee well-being over time

The effects of work-family conflict on the well-being of a diverse sample of 342 non-professional employees from the greater Los Angeles area were examined. Data were collected at two points in time, and a rigorous research design was employed. The effects of self-report bias were considered by controlling for social desirability bias, and by collecting two sources of data (i.e. self-reports and co-workers reports). The results revealed that work-family conflict predicted employee well-being over and above social desirability bias. In addition, analyses were consistent when both self-reports and co-workers reports were utilized. Finally, work-family conflict was a longitudinal predictor of employee's positive well-being. Both cross-sectional and longitudinal analyses were consistent across self-reports and co-worker reports.     

Policy Goals for Health and Safety

Health management and safety regulation are separate disciplines but share the aim to extend expectancy of life in good health. The need to improve cost-effectiveness calls for their co-ordinated management according to a unified rationale. Three guiding principles of accountability, demonstrable net benefit and a uniform measure of performance, have been laid out in Canada by the Joint Committee on Health and Safety. They call for open accounting in terms of (health-related quality-adjusted) life expectancy. The principles are utilitarian in format but, it is argued, inequity is naturally diminished in the process of optimizing cost-effectiveness through maximum marginal returns. Comments are made on practical implementation. The need for public consent in practice calls for two additional principles reflecting fair procedure and sovereignty of the citizens. It is concluded that public health and safety measures should be surveyed, documented for cost-effectiveness and prioritized for improvement.     

The impact of a participatory organizational intervention on job stress in community health care institutions

The aim of the present study was to investigate the effect of a short-term participatory intervention in health care institutions in Norway on workers' control, other job characteristics, job stress, subjective health and job satisfaction. Participants (including managers and supervisors) were randomly allocated to intervention groups and to a control group. Actions to solve problems based on the employees' own perceptions of the main problems were seen as the key motivators for organizational improvement and increased control at the task and office level in the work situation. The main stressors identified by the participants in this study were lack of information, communication and respect between professions, as well as the need for professional and personal development. The participatory intervention had a positive, but limited effect on work-related stress, job characteristics, learning climate and management style, and seemed to have started a beneficial change process. There were no negative short-term effects on work-related stress and job demands. Organizational interventions may be a potential training ground for acquiring participatory skills and resources, and if sustained after the intervention period, they can have long-term effects on problem solving, job stress and employee satisfaction.     

Circadian Rhythm and the Business Person

Each human being has an internal timekeeping mechanism. To date, over 100 so-called circadian rhythms have been detected. Perhaps the most significant is body temperature. There is an apparent connection between this rhythm and the efficiency with which we do things in the course of the working day. Within individuals, patterns have been discovered which give credence to the popular notions of a morning or an afternoon person, and so on. Our memory changes from morning to afternoon: short-term memory is stronger in the morning, and long-term memory stronger in the afternoon; in schools, morning students have higher grades than students who have other time-of-day preferences. Therefore, a strong case can be made in support of flexible time schedules. It is reported that productivity went up on the introduction of such a scheme. Employee stress has been seen to decline also. When flextime was offered, parents with small children took advantage of the benefit as well as unmarried employees. The only drawback is ensuring that, with so many individual variations in preferences, the needs of the company are fully met. If such a scheme can be devised, however, the research suggests that productivity and efficiency will increase.