卖空限制、意见分歧收敛与信息披露的股价效应——来自A股市场的经验证据

本文从盈余公告对投资者意见分歧影响的角度,解释A股市场年报公告期间的股价反应,在为意见分歧资产定价理论提供经验证据的同时,也为A股市场信息披露股价效应的研究提供一个全新的思路。研究发现,公告前投资者意见分歧程度与股票在公告日附近的超额收益负相关,证明上市公司年报会降低投资者的意见分歧,导致公告前因卖空限制和意见分歧而被高估的股价在公告日附近向其基础价值靠拢。此外,本文还发现上述股价反应在正式公告日前的几个交易日就已出现,证明A股市场存在年报信息提前泄露的情况。进一步研究显示,意见分歧与公告日附近股票超额收益的负相关关系随着机构持股比例和行业集中度的提高而逐渐增强。     

A股市场盈余公告效应：基于投资者意见分歧视角

以A股市场上市公司定期披露的年报为研究对象,对年报披露期间投资者意见分歧变动与盈余公告效应的关系进行研究,发现投资者意见分歧会对盈余公告效应产生影响,两者呈负相关关系,负相关程度随持有期的延长而逐渐增强。意见分歧与盈余公告效应的负相关关系在好消息和坏消息组中都存在。有别于已有研究,发现意见分歧对盈余公告效应的影响随着股票流动性的降低而更加明显。     

投资者意见分歧对盈余公告效应影响的实证研究

从投资者意见分歧的角度对盈余公告效应进行理论解释,借鉴衡量投资者意见分歧的模型对中国股票市场的盈余公告效应进行实证检验,研究结论认为:我国的股票市场表现出了明显的盈余公告效应.投资者意见分歧对盈余公告效应具有很好的解释作用.在研究期内,投资者意见分歧与股票组合的累积异常收益率呈正相关关系.     

投资者异质后验信念对股票价格影响的实证研究

过度自信程度不同的投资者因消息确认精度差异引起意见分歧,产生异质后验信念,导致投资者对股价高估或者低估。在此基础上,以盈余公告信息作为利好或利空消息,研究不同环境下异质后验信念对我国股票价格的影响。实证结果表明:不管在牛市还是在熊市环境下,异质后验信念均会对股价产生影响,当盈余公告为利好消息时,异质后验信念程度越高,当期股价被高估的程度越显著;当盈余公告为利空消息时,异质后验信念程度越高,当期股价被低估的程度越显著。此外,在盈余公告前投资者就对盈余消息作出了反映,但对好消息与坏消息的反映程度不同。     

个人投资者能够解读公开信息吗?——基于盈余公告附近信息需求行为的研究

本文使用百度超额搜索量作为个人投资者信息需求行为的代理变量,发现在盈余公告附近,个人投资者对公司信息的需求明显增强。随着投资者信息需求的增强,股票的交易量也随之增加。盈余公告前的投资者信息需求行为不影响同期股价对未预期盈余的反应,但是对盈余公告之后的盈余反应系数具有显著的负向作用,这为Holthausen和Verrecchia(1990)、Kim和Verrecchia(1997)的理论模型提供了来自中国市场的证据。本文还发现盈余公告之后的信息需求使市场对盈余公告的立即反应更加充分;此外,业绩预告、新闻报道等影响着个人投资者对公开信息的解读。     

盈余公告效应影响因素分析

盈余公告效应被发现后,投资者最为关注的是它所带来的超额收益,本文检验了上市公司的规模、非预期盈余和账面市值率三个因素对中国沪市A股市场盈余公告后超额收益影响的影响,并根据这结论,提出了投资策略建议。     

盈余公告效应影响因素分析

盈余公告效应被发现后,投资者最为关注的是它所带来的超额收益,本文检验了上市公司的规模、非预期盈余和账面市值率三个因素对中国沪市A股市场盈余公告后超额收益影响的影响,并根据这结论,提出了投资策略建议.     

盈余管理、投资者情绪与股价“同涨同跌”

上市公司的盈余管理和投资者情绪是否影响了股价的"同涨同跌"(股价同步性),证券市场信息效率是否因此受到了影响?本文采用2002～2010年中国股市和上市公司样本,用R2度量股价同步性,检验在不同市场不确定性下盈余管理和投资者情绪对股价同步性的影响。研究发现:管理者盈余管理使得股价同步性降低,而投资者情绪波动使得股价同步性上升;但是,两者均导致股票收益的"惯性"或"反转"效应增强,即市场信息效率下降。因此,本文认为不能简单地以股价同步性的高低来衡量股价的信息效率,需结合影响股价同步性的信息不对称和心理因素进行新的解释。     

融资融券交易与市场价格发现——基于盈余公告漂移的实证分析

融资融券的推出是中国证券市场交易制度的一次结构性的变革,本文以第一批可以融资融券的90只股票为样本,选取盈余公告漂移异象作为研究标的,从理论和实践角度检验融资融券推出对市场价格发现的影响作用.我们发现,融资融券的推出使得投资者有更多的选择和手段对市场信息做出及时反应,A股市场的一个市场异象盈余公告漂移在融资融券后有显著减弱.最后本文利用融资融券制度的可卖空和杠杆交易特征构造了基于盈余漂移的交易策略.     

分析师修正信息、基本面分析与未来股票收益北大核心CSSCISSCI

本文基于日历时间组合方法检验中国A股市场分析师修正信息的投资价值。研究发现,分析师发布的盈余预测修正和投资评级修正最具信息含量,投资者既未充分意识到两类修正的信息含量,也未充分意识到明星分析师和普通分析师能力的差别。根据分析师盈余预测修正和投资评级修正构建套利组合,能分别获得月均1.34%和0.92%的经三因子模型调整的超额收益。本文进一步指出,分析师修正信息的投资价值来源于其基本面分析的能力。分析师盈余预测修正和投资评级修正能够显著预测公司未来的盈利能力、标准化未预期盈余和盈余公告窗口期超额收益,并且套利组合的超额收益集中在盈余公告窗口期。本文的结论对于理解分析师在资本市场中发挥的作用、提高市场有效性具有重要意义。     

Does Shareholder Composition Matter? Evidence from the Market Reaction to Corporate Earnings Announcements

We examine whether institutional ownership composition is related to parameters of the market reaction to negative earnings announcements. When firms report earnings below analysts' expectations, the stock price response is more negative for firms with higher levels of ownership by momentum or aggressive growth investors. There is no evidence, however, that these institutions cause an “overreaction” to earnings news. Ownership structure is also related to trading volume and to stock price volatility on days around earnings announcements. Our findings are consistent with the idea that the composition of institutional shareholders effects stock price behavior around the release of corporate information.     

Earnings Announcements,Differences of Opinion and Management Guidance

Berkman, Dimitrov, Jain, Koch, and Tice (2009) document a negative relationship between differences of opinion and earnings announcement returns, and this relationship is more pronounced when short‐sale constraints are likely to be high. These findings are interpreted as support for the theory in Miller (1977) that binding short sale constraints cause pessimists to be underrepresented in price formation. We conjecture that accounting information (i.e., earnings news) is likely to play a role in this returns pattern. After controlling for the level of earnings news, we find that the relationship between differences of opinion and stock returns is either eliminated or opposite from what is predicted by Miller's theory. Further, we present evidence that suggests the confounding effect of earnings news can be explained by (pessimistic) management earnings guidance. Our findings offer an alternative explanation for why low differences of opinion stocks earn greater abnormal returns around earnings announcements.     

Too Good to be True? An Analysis of the Options Market's Reactions to Earnings Releases

Using option implied risk neutral return distributions before and after earnings announcements, we study the option market's reaction to extreme events over earnings announcements. While earnings announcements generally reduce short‐term uncertainty about the stock price, very good news does not reduce uncertainty and slightly bad news actually increases uncertainty. We also find that left tail probabilities decrease over earnings releases while right tail probabilities increase. We interpret these findings as evidence of maintained investor expectations that very good news is generally not released during earnings announcements, combined with skepticism in the form of lingering uncertainty at the release of such very good news.     

Options trading volume and stock price response to earnings announcements

We examine the effect of options trading volume on the stock price response to earnings announcements over the period 1996–2007. Contrary to previous studies, we find no significant difference in the immediate stock price response to earnings information announcements in samples split between firms with listed options and firms without listed options. However, within the sample of firms with listed options stratified by options volume, we find that higher options trading volume reduces the immediate stock price response to earnings announcements. This conforms with evidence that stock prices of high options trading volume firms have anticipated and pre-empted some earnings information in the pre-announcement period. We also find that higher abnormal options trading volume around earnings announcements hastens the stock price adjustment to earnings news and reduces post-earnings announcement drift.     

Insider trading,future earnings,and post-earnings announcement drift

This paper examines the association between insider trading prior to quarterly earnings announcements and the magnitude of the post-earnings announcement drift (PEAD). We conjecture and find that insider trades reflect insiders’ private information about the persistence of earnings news. Thus, insider trades can help investors better understand and incorporate the time-series properties of quarterly earnings into stock prices in a timely and unbiased manner, thereby mitigating PEAD. As predicted, PEAD is significantly lower when earnings announcements are preceded by insider trading. The reduction in PEAD is driven by contradictory insider trades (i.e., net buys before large negative earnings news or net sells before large positive earnings news) and is more pronounced in the presence of more sophisticated market participants. Consistent with investors extracting and trading on insiders’ private information, pre-announcement insider trading is associated with smaller market reactions to future earnings news in each of the four subsequent quarters. Overall, our findings indicate insider trading contributes to stock price efficiency by conveying insiders’ private information about future earnings and especially the persistence of earnings news.     

Are corporate managers savvy about their stock price? Evidence from insider trading after earnings announcements

We find that insiders trade as if they exploit market underreaction to earnings news, buying (selling) after good (bad) earnings announcements when the price reaction to the announcement is low (high). We also find that insider trades attributable to public information about earnings and the price reaction generate abnormal returns. By demonstrating that managers spot market underreaction to earnings news, our results imply that managers are savvy about their company’s stock price.     

Short sale constraints,heterogeneous interpretations,and asymmetric price reactions to earnings announcements

This study tests Miller’s (1977) overpricing hypothesis from a new angle. Specifically, we investigate the effects of heterogeneous interpretations on price reactions to earnings announcements. We find that the difference between good news and bad news earnings response coefficients increases with the degree of heterogeneous interpretations in the presence of short sale constraints. This pattern is more pronounced when short sale constraints are more binding. These findings support the notion that, under short sale constraints, stock prices selectively incorporate more optimistic opinions rather than the average opinion of all investors. Therefore, reducing short sale constraints should facilitate price discovery and improve price efficiency. This study complements recent studies examining the joint effect of short sale constraints and ex ante opinion divergence on price reactions to earnings announcements.     

Option trading: Information or differences of opinion?

This paper investigates the motive of option trading. We show that option trading is mostly driven by differences of opinion, a finding different from the current literature that attempts to attribute option trading to information asymmetry. Our conclusion is based on three pieces of empirical evidence. First, option trading around earnings announcements is speculative in nature and mostly dominated by small, retail investors. Second, around earnings announcements, the pre-announcement abnormal turnovers of options seem to predict the post-announcement abnormal stock returns. However, once we control for the pre-announcement stock returns, the predictability completely disappears, implying that option traders simply take cues from the stock market and turn around to speculate in the options market. Third, cross-section and time-series regressions reveal that option trading is also significantly explained by differences of opinion. While informed trading is present in stocks, it is not detected in options.     

When Is Bad News Really Bad News?

We examine whether the price response to bad and good earnings shocks changes as the relative level of the market changes. The study is based on a complete sample of annual earnings announcements during the period 1988 to 1998. The relative level of the market is based on the difference between the current market P/E and the average market P/E over the prior 12 months. We find that the stock price response to negative earnings surprises increases as the relative level of the market rises. Furthermore, the difference between bad news and good news earnings response coefficients rises with the market.     

Sell on the news: Differences of opinion,short-sales constraints,and returns around earnings announcements

Miller [1977. Risk, uncertainty, and divergence of opinion. Journal of Finance 32, 1151–1168] hypothesizes that prices of stocks subject to high differences of opinion and short-sales constraints are biased upward. We expect earnings announcements to reduce differences of opinion among investors, and consequently, these announcements should reduce overvaluation. Using five distinct proxies for differences of opinion, we find that high differences of opinion stocks earn significantly lower returns around earnings announcements than low differences of opinion stocks. In addition, the returns on high differences of opinion stocks are more negative within the subsample of stocks that are most difficult for investors to sell short. These results are robust when we control for the size effect and the market-to-book effect and when we examine alternative explanations such as financial leverage, earnings announcement premium, post-earnings announcement drift, return momentum, and potential biases in analysts’ forecasts. Also consistent with Miller's theory, we find that stocks subject to high differences of opinion and more binding short-sales constraints have a price run-up just prior to earnings announcements that is followed by an even larger decline after the announcements.