IPO发行价溢价异象与投资者情绪研究

以2003—2011年沪深两市所有A股作为样本进行研究可以发现,IPO发行价与IPO溢价之间存在显著的负相关关系,IPO发行价越低,IPO溢价现象越明显,称之为“发行价溢价异象”。采用受限因变量Tobit模型对投资者结构进行分析又可发现,IPO发行价越低,个人投资者持股比例越高,机构投资者持股比例越低．由此表明,正是由于低发行价股票投资以个人投资者为主,个人投资者易于受到投资者情绪影响,高估股票价值,增加非理性投资需求,寸导致了“发行价溢价异象”产生。     

A Characterization for Dominant Strategy Implementation

We introduce a perfect price discriminating mechanism for allocation problems with private information. A perfect price discriminating mechanism treats a seller, for example, as a perfect price discriminating monopolist who faces a price schedule that does not depend on her report. In any perfect price discriminating mechanism, every player has a dominant strategy to truthfully report her private information.We establish a characterization for dominant strategy implementation: Any outcome that can be dominant strategy implemented can also be dominant strategy implemented using a perfect price discriminating mechanism. We apply this characterization to derive the optimal, budget-balanced, dominant strategy mechanisms for public good provision and bilateral bargaining.     

中国股市机构投资者多账户交易行为研究

多账户交易行为是中国机构投资者的典型特征,是中国股票市场的特有现象。限于交易数据的可获得性,相关研究较少。本文提出了一种从交易数据中将机构投资者的交易记录分离出来的方法。据此,本文分析了机构投资者证券账户与资金账户的对应关系,证实了多账户交易行为的存在,发现采用多账户交易的机构投资者具有集中投资、日内多次交易、利用不同证券账户进行建仓、对敲、拉升股价、出货等基本特征。根据实证研究的结果并结合实例,本文揭示了机构投资者多账户交易的动机是隐蔽交易、拉升股价和申购新股。     

Does individual investors’ attention influence underwriters’ IPO pricing?

ABSTRACT

Using a unique Chinese IPO bidding dataset and a particular social media dataset, we examine the impact of individual investors’ attention on underwriters’ offer price adjustment, offer price revision, IPO initial returns, and long-term performance. We find that when a company receives more attention from individual investors before the underwriter finalizes the offer price, the underwriter will adjust the offer price higher. Moreover, we find that the IPO initial returns are significantly positively related to individual investors’ attention. These findings suggest that individual investors will influence underwriters’ pricing behaviour from a new perspective, – –investors’ attention. Finally, we do not find a significant relationship between individual investors’ attention and IPO long-run performance.     

中国IPO定价效率研究 ——基于IPO抑价率和EFF值的比较分析

IPO定价效率是IPO市场的一个研究热点。本文以沪深A股市场首次公开发行并上市的新股为样本,通过IPO抑价率和EFF值指标比较分析了IPO定价效率的行业特征和定价制度特征。研究表明：EFF均值在行业之间的差异不显著,而IR均值在行业之间差异显著;我国IPO定价效率未随时间推移而不断提高,EFF值和IR值呈现出无趋势的特征。在此基础上,本文认为我国IPO定价效率不高的主要原因不是一级市场低价发行,而是二级市场投资者的追捧和半市场化性质的改革,提高IPO定价效率的根本途径在于回归市场化改革。     

Private information,Coasian bargaining,and the second welfare theorem

Most of the debate about Coasian bargaining in the presence of externalities relates to the First Welfare Theorem: is the outcome under bargaining efficient? This debate has involved the definition and importance of transaction costs, the significance of private information, and the effect of entry. There has been little analysis of how Coasian bargaining relates to the Second Welfare Theorem: even if the bargaining outcome is efficient, does the process limit the set of Pareto optimal allocations which can be achieved?We consider a model in which individuals utilize a common resource and may affect each other's output. The individuals differ in their productivities or tastes and this information is private to each of them. The government can manage the common resource and use nonlinear taxes to correct for the externality or it can turn the common resource over to a private owner who can charge individuals to utilize it with a nonlinear fee schedule. The government and the owner have the same information about tastes and productivities of the individuals. Except for the private information, there are no bargaining or administrative costs for collecting the taxes or fees. Whether there is public or private ownership, the government desires to redistribute, but it faces self-selection constraints.We show that the outcome of Coasian bargaining is constrained Pareto efficient. That is, given the information constraints, no Pareto improvement is possible. However, private ownership may limit what Pareto optimal allocations the government can achieve. The private owner in seeking to maximize profits always proposes contracts which counteract the government's attempts to redistribute across individuals with different characteristics. Under public management, any Pareto optimum can be sustained. In this context, private ownership, while not inefficient, does limit the government's ability to redistribute.     

研发信息披露与IPO定价效率

本文采用人工阅读招股书并打分的模式构建研发信息披露得分指标,并从一级市场定价效率与首次公开募股(initial public offering,IPO)抑价2个维度解释研发信息披露对IPO定价效率的影响.对2012—2018年间459只创业板IPO新股样本进行研究,双边随机前沿模型的检验结果表明:一级市场上股票发行定价明显偏高,研发信息披露提高了一级市场定价效率;而股票上市后,研发信息披露与IPO抑价率无显著关系,这显示了中国二级市场大部分投资者尚不具备能合理利用研发信息的专业知识,不能有效利用企业在招股书中披露的研发信息.本文的研究结论为监管部门完善研发信息披露制度,培养理性投资者提供了理论支持.     

国有机构投资者持股能提升企业投资效率吗?

具有国资背景的机构投资者,对于资本市场平稳发展具有重要意义。本文基于我国2015—2019年A股上市公司样本,考察持股对企业投资效率的影响。研究发现,持股显著提升了企业投资效率,并且该影响在代理冲突更严重和所处信息环境更不透明的公司中更加显著。机制检验表明,降低企业内外部信息不对称和代理成本是持股提升企业投资效率的重要渠道。进一步研究发现,国有机构投资者持股时间越长,对企业非效率投资的治理效果越好;细分国有机构投资者类型后发现,致力于长期维护资本市场稳定和上市公司长期健康发展的证金公司和汇金公司对企业投资效率的提升作用显著,但没有发现“救市”基金和外管局旗下的投资平台对企业投资效率有提升作用。研究结论从企业投资效率视角为国有机构投资者持股在微观企业日常经营中发挥的治理作用提供了新颖的经验证据,对进一步提高我国上市公司质量具有启示意义。     

Optimal auctions with information acquisition

This paper studies optimal auction design in a private value setting with endogenous information gathering. We develop a general framework for modeling information acquisition when a seller wants to sell an object to one of several potential buyers, who can each gather information about their valuations prior to participation in the auction. We first demonstrate that the optimal monopoly price is always lower than the standard monopoly price. We then show that standard auctions with a reserve price remain optimal among symmetric mechanisms, but the optimal reserve price lies between the ex ante mean valuation of bidders and the standard reserve price in Myerson (1981). Finally, we show that the optimal asymmetric mechanism softens the price discrimination against “strong” bidders.     

How does the diversity of investors’ beliefs affect stock price informativeness?

A growing number of studies have investigated the role of stock prices in aggregating private information and guiding resource reallocation. However, this article may be the first attempt to study how the diversity of beliefs affects stock price informativeness. The framework of the noisy rational expectations model shows that stock informativeness is determined by both the precision and use of private information in trading. If private beliefs about the value are highly diverse, the aggregate average opinion revealed in a stock’s price will be more accurate and, thus, more informative. As the price becomes more informative, however, individual investors will rely less on their private information. When this occurs, less private information will be absorbed in price, which, in turn, reduces price informativeness. Our model shows that the relationship between belief diversity and price informativeness is U-shaped in equilibrium.     

Portfolio choice, attention allocation, and price comovement

This paper models the attention allocation of portfolio investors. Investors choose the composition of their information subject to an information flow constraint. Given their expected investment strategy in the next period, which is to hold a diversified portfolio, in equilibrium investors choose to observe one linear combination of asset payoffs as a private signal. When investors use this private signal to update information about two assets, changes in one asset affect both asset prices and may lead to asset price comovement. The model also has implications for the transmission of volatility shocks between two assets.     

私募股权、天使资本对创业板市场IPO抑价的不同影响

文章对我国创业板市场的上市前股权投资者进行了界定和区分,然后采用手工整理数据考察了私募股权资本和天使资本对创业板公司的投资行为,重点研究了这两种资本对IPO抑价率的不同影响。研究发现,目前我国的私募股权资本往往投资于高估值行业且入股的企业资质较差,不能发挥认证作用,其持股的公司有更高的IPO抑价率;相反,天使资本往往投资于资质较好的企业,并且愿意投资负债率较高的企业,其持股对IPO抑价率无显著影响。在此基础上,文章对创业企业审慎选择融资来源、私募股权投资机构进行理性投资以及监管部门加强行业引导等方面提出了建议。     

Do Irrational Investors Destabilize?

In a financial market where all investors have valuable private information, full rationality requires that investors have an unlimited ability of figuring out the equilibrium model. Instead, I assume that due to a lack of knowledge or experience, some investors do not know the equilibrium model and use only their private information in forming their demand. By investigating the investment behavior of these “boundedly rational” investors and contrasting it with that of the rational ones, I find that in a market where the two kinds of investors coexist, it is the boundedly rational investors who contribute to price stability. The welfare implication is that, although each investor benefits from conditioning his asset demand on the information transmitted by the equilibrium price, it can happen that all investors lose by doing so because the equilibrium price becomes too volatile.     

IPO股票上市初期投资者交易行为研究

区别于国内以股票价格为对象揭示IPO股票特征的研究,文章以投资者为研究对象,研究中国IPO股票上市初期机构和个人投资者的交易行为差异。IPO交易研究是目前IPO研究的一个前沿领域。文章利用沪深股市2002年IPO股票的账户交易数据建立Logistic回归模型发现,中国IPO股票上市首日的高成交量与高换手率由投资者逐利行为造成;在上市后3日的交易中,个人投资者由于资金限制和信息获取能力不足等原因,对股票收益的判断能力明显弱于机构投资者,在交易中被机构投资者所利用。     

环境信息披露与企业经营绩效——基于投资者关注的中介效应检验

经济高质量发展背景下,企业环境信息披露已经引起全社会的普遍重视。本文基于沪深A股上市公司2007—2019年样本企业面板数据,以投资者关注为中介变量,揭示环境信息披露对企业经营绩效的作用机制。结果显示,环境信息披露对企业经营绩效具有显著的正向激励作用,投资者关注发挥部分中介效用。进一步的研究表明,将机构投资者持股比例作为门槛变量时,存在显著的单一门槛效应,当企业引入机构投资者持股比例高于一定门槛值时,环境信息披露能显著提升企业经营绩效,否则激励效果不显著;同时异质性分析发现,重污染行业及2015年后环境信息披露对企业经营绩效激励效果更为显著。本文研究结论有助于企业更理性地认识环境信息披露的经济效益,为政府、企业和投资者共同构建高质量环境信息披露体系提供思路。     

机构投资者如何影响企业创新——兼论机构投资者与企业异质性

机构投资者作为我国资本市场的重要组成部分,在公司治理外部监管等方面发挥着不可小觑的作用。将公司治理传导效应纳入机构持股与企业创新关系及作用机理分析框架,基于2007—2018年A股上市公司数据进行实证检验。结果发现,机构投资者持股显著促进企业创新,内部控制有效性、核心技术人员股权激励和管理费用控制是机构投资者促进企业创新的3个重要传导路径。另外,战略型机构投资者对企业创新的影响相较于财务型机构投资者更为突出;同时,机构投资者对非国有企业创新存在显著促进作用,但对国有企业整体创新的影响不显著。     

投资者的异质预期对IPO抑价的影响

针对IPO抑价中的有意抑价和无意抑价问题,运用行为金融理论,在以机构投资者利益最大化推导出机构投资者需求函数的基础上,研究了散户和机构投资者的同质和异质预期对IPO抑价的影响,并进行抑价进行比较分析。研究表明:机构投资者具有有意抑价的激励;当机构投资者与散户对新股价值不存在分歧时,IPO抑价中只有有意抑价,而无无意抑价;当机构投资者与散户对新股价值存在分歧时,分歧越大,IPO抑价越高,而抑价中的有意抑价不变、无意抑价增大。     

Rational expectations,difference of opinions and asset pricing

This article applies the concept of relative overconfidence (the measure of how heavily investors depend on others’ information) to combine the rational expectations equilibrium (REE) and difference of opinions (DO) models. And we discuss the effects of relative overconfidence on asset price efficiency and trading volume. We find that when investors hold assets to maturity, relative overconfidence has no effect on price efficiency and trading volume; however, when investors speculate, relative overconfidence reduces price informativeness and trading volume, because investors will reckon asset prices as more noisy and find it meaningless to speculate on capital gains based on their private information. Our results highlight the role of speculation in differentiating REE and DO models and influencing the effects of overconfidence.