并购重组前的知情交易行为研究

并购重组中基于内幕信息的知情交易行为既是监管重点,也是学术界关注的热点问题。本文以2006—2020年我国上市公司并购重组事件为样本,考察并购重组前的知情交易行为对并购公告收益的影响。研究发现：并购重组前的知情交易行为引发了主并公司股价的提前反应,从而降低了并购公告时的市场反应,这一现象是由内幕信息泄露引起,且内幕信息主要来源于包括员工在内的公司内部人,而非机构投资者。进一步分析表明,改善信息环境可以有效缓解并购重组的信息泄露问题,体现为知情购买交易的信息泄露效应受到分析师跟踪、审计质量和问询函制度的有效制约。本文研究深化了现有的并购重组内幕交易行为研究,为实施精准监管和防范内幕交易等政策提供了一定参考和依据。     

卖空者与内幕交易——来自中国证券市场的证据

本文研究上市公司内部人减持、年报、诉讼、分析师评级、停复牌以及高送转等重大公告前后卖空交易行为的变化,系统考察卖空者是否参与内幕交易以及何种因素影响卖空者参与内幕交易,发现卖空率较高的股票具有较低的未来收益,表明卖空者拥有信息优势,属知情交易者;卖空者拥有非常精确的择时交易能力,在重大利空公告前显著增加卖空量,而在利好公告前则显著减少卖空头寸,表明卖空者作为知情交易者的信息优势源自内幕消息;公司内、外部投资者的信息不对称程度越低或公司所在地的法治水平越高,卖空者参与内幕交易的行为就越少。因此,监管机构应密切关注公司重大消息发布前后卖空量的异常变动,同时,完善信息披露规则、健全证券分析师制度并强化法律法规的执行力度,才能有效防范卖空者参与内幕交易。     

卖空机制能够约束内部人减持吗？——基于融资融券制度的经验证据

本文以我国放松卖空管制为视角,探究其对内部人减持的影响。研究表明,卖空机制能够抑制企业内部人减持行为。机制分析发现,卖空对内部人减持的抑制作用是通过缓解股权高溢价实现的。进一步研究表明,卖空能够抑制大股东、董事以及管理层减持,但对监事减持无影响;卖空能够降低内部人减持的获利程度,并且在内部人减持动机更大时,对内部人减持的抑制作用更强;卖空通过约束内部人减持提升了股票定价效率,还有助于降低内部人增持行为。本文的研究结论丰富了卖空和内部人减持领域的文献,并对政府部门完善制度设计具有启示意义。     

IQ and corporate insiders’ decisions to time insider and outsider trading

We examine how corporate insiders’ cognitive ability (IQ) affects their decisions to time insider and outsider trading before abnormal stock price changes. Our analysis of archival data on male corporate insiders in Sweden shows they are less prone to time their insider selling and to sell in larger amounts, before abnormal stock price declines as IQ increases. We also find that insiders with a higher IQ are better at timing their outsider buying. Taken together, our results show that corporate insiders’ IQ affects their trading decisions differently, depending on whether they are trading in their insider or outsider stocks.     

Sell-side analyst heterogeneity and insider trading

This study explores insider trading patterns under different earnings surprises. After controlling for stock market liquidity and earnings announcements returns, we show that insiders sell more aggressively depending on the heterogeneity of analysts whose EPS forecasts are met or beaten to camouflage their trades. Specifically, insiders sell more shares of their company sooner after the publication of earnings when top analysts' forecasts are met or beaten. Consistent with the informed trading literature, insiders strategically select these moments because the stock price impact is low and the legal scrutiny of their trades is minimal. To support this result, we employ an exogenous drop in firms' analyst coverage due to the closure or merger of brokerage houses. Furthermore, in line with the camouflage incentives, by selling after top analysts' forecasts are met or beaten, stock prices adjust slowly to insider trades. Finally, we show that the incentives of insiders to hide their trades are concentrated in opportunistic insiders and members of the top management team, who are more likely to bear the costs of selling shares after positive news.     

Insider trading and firm-specific return volatility

Roll (J Financ 43:541–566, 1988) argues that firm-specific stock return volatility may result either from informed trading or from noise trading that is unrelated to information. In this paper we provide evidence that insider purchases are inversely related to the idiosyncratic volatility of stocks. We also find that stock idiosyncratic volatilities are generally inversely related to future 6- and 12-month returns. Our results are primarily driven by the timing of insider sales rather than insider purchases. The results are consistent with an information-based explanation of firm-specific return volatility.     

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.     

Information‐Hedging Disclosures and Insider Trading

I model the effect of disclosure on the tradeoff between information risk, liquidity risk, and price risk for a well‐informed, risk‐averse insider. Revealing some information before trading decreases the variability of the insider's information advantage and thus reduces his information risk. Disclosure also lowers adverse selection costs for market makers, which reduces the insider's liquidity risk by increasing his trading flexibility. However, disclosure increases price risk for the insider because the price fully reflects the revealed information. The reduction in information and liquidity risks outweigh the rise in price risk when the insider is less risk averse because a less risk‐averse insider's information‐based motive for trading is stronger than his hedging motive. The opposite relation holds when the insider is more risk averse. Therefore, a less (more) risk‐averse insider experiences an increase (decrease) in welfare when he discloses some information before trading. Cost of capital and policy implications are identified.     

Venture Capital Distributions: Short-Run and Long-Run Reactions

Venture capital distributions, a legal form of insider trading, provides an ideal arena for examining the share price impact of transactions by informed parties. These sales, which occur after substantial run-ups in share value, generate a substantial price reaction immediately around the event. In the months after distribution, returns apparently continue to be negative. When the short- and long-run reactions are decomposed, they are consistent with the view that venture capitalists use inside information to time stock distributions: Distributions of firms brought public by lower quality underwriters and of less seasoned firms have more negative price reactions.     

Insider transfer trading of banking companies around exchange listing

This paper examines insider transfer trading of banking companies before and after their listing on the Taiwan Stock Exchange. During the pre-listing period, we uncover significantly negative abnormal returns after insiders announce their plans to transfer stocks, as well as significant price reversals following the subsequent disclosure of unfulfilled transfers. However, after listing, we observe little market response to the initial announcement, and nor is any price revision observed for partial/no transfer information. For both periods, the substantial increases in turnover provide further evidence on the flow of information from insider trading. Additionally, the propensity and profitability of insider transfers are documented. Overall, empirical results indicate that dissemination of information on insider transfer trading before listing can negatively influence the stock price, while information on insider transfers posted after listing attracts only limited attention. Consequently, the evidence is consistent with the implications associated with the managerial timing of listing decisions.     

Information Production, Insider Trading, and the Role of Managerial Compensation

We analyze the information production decision of a manager who can trade on this information and whose compensation is increasing in the stock price. The amount of information produced increases with the stock's volatility and liquidity and decreases with the manager's pay-performance sensitivity. Insider trading regulations that symmetrically inhibit the manager's ability to buy and sell stock cause her to produce less information. But asymmetric insider trading regulations like the short sales prohibition have an ambiguous effect inducing her to produce more or less information depending on her pay-performance sensitivity. This contradicts the standard argument made by opponents of insider trading regulations that such regulations always reduce information production.     

Insider Trading around Dividend Announcements: Theory and Evidence

The informational role of strategic insider trading around corporate dividend announcements is studied based on the efficient equilibrium in a signalling model with endogenous insider trading. Insider trading immediately prior to the announcement of dividend initiations has significant explanatory power. For firms with insider selling prior to the dividend initiation announcement, the excess returns are negative and significantly lower than for the remaining firms (with no insider trading or just insider buying) as implied by our model. Another implication is that dividend increases may elicit a positive or negative stock price response depending on the firm's investment opportunities.     

基于面板数据的我国知情交易与股价信息含量研究

知情交易概率是指知情交易委托单占总交易委托单的比重,用于度量我国知情交易强度。R2代表公司回报率能被市场回报率解释的程度,R2越大,股价信息含量越低。在以往的研究基础上,利用面板数据来考察知情交易概率与股价信息含量的关系,发现知情交易概率越低,R2越高,股价信息含量越低。在控制了流动性与部分公司财务指标后,实证结果依然显示我国股价信息含量与知情交易概率存在正相关关系,说明我国知情交易者进行交易时,更有利于公司特质信息进入股票价格。     

Insider Trading and Corporate Information Transparency

Our study examines the relation between insider trading and corporate information transparency. We find a negative relation between firms’ information transparency and the economic significance of insider trading, including the amount of insider purchase and sale and the profitability of insider transactions. We also find a negative relation between information transparency and stock price reaction to news of insider trading, which suggests that increases in information transparency preempt insiders’ private information. Our study provides evidence consistent with firms’ transparency-enhancing activities decreasing information asymmetry between insiders and investors by revealing insiders’ private information to investors in a timely manner.     

Can insiders bail themselves out before private renegotiation?

This study examines insider trading for a sample of firms that announce a workout agreement, controlling for both successful and unsuccessful workout attempts. I find that insider trading activity is related to the outcome of the workout proposal. Managers tend to bail out (sell shares) of firms that are unsuccessful in the workout process while they purchase shares prior to the workout announcements if the firms are ultimately successful in their workout. In addition, the evidence suggests managerial trading behavior is related to the workout market reaction. When a workout announcement is preceded by insider buying (selling), the stock price reaction is positive (negative). Overall, the evidence presented in this article is consistent with the notion that insider transactions convey private information to the stock market about a financially distressed firm.     

Multimarket trading and market liquidity

When a security trades at multiple locations simultaneously,an informed trader has several avenues in which to exploit hisprivate information. The greater the proportion of liquiditytrading by 'large' traders who can split their trades acrossmarkets, the larger is the correlation between volume in differentmarkets and the smaller is the informativeness of prices. Weshow that one of the markets emerges as the dominant locationfor trading in that security. When informed traders can usetheir information for more than one trading period, the timelyrelease of price information by market informed traders expectto make subsequently at other locations. Markets makers, competingto offer the lowest cost of trading at their location, consequentlydeter informal trading by voluntarily making the price informationpublic and by 'cracking down' on insider trading.     

Insider stock pledging and stock price informativeness: Evidence from India

Insiders’ shares can act as collateral while raising funds from lenders. This study examines the impact of insiders’ stock pledging activities on stock price informativeness using a sample of 1835 Indian firms. Our findings report that insider stock pledging increases the informational efficiency of stock prices. This informational efficiency increases for larger firms with: (1) financial constraints (high leverage and low cash holdings); (2) greater reliance on trade credit; and (3) higher indulgence in related party transactions. We also provide evidence on abnormal share turnover as a trading mechanism through which insider stock pledging is related to stock price informativeness. Our findings are robust across different specifications and after accounting for endogeneity issues.     

Trading on inside information: Evidence from the share-structure reform in China

We examine stock trading activities in days before Chinese listed firms made public announcement to start share-structure reform. There is significant evidence that, relative to a benchmark period, institutional investors bought more event firms’ shares in the last two trading days prior to announcement. Randomization tests show significant differences in institutional trading activities between event firms and matched control firms, which suggests that some institutions had inside information. Moreover, large trades account for a significant proportion of daily stock price changes in the last 2 days. The evidence is consistent with the prediction by Holden and Subrahmanyam (1992) that, when multiple informed investors acquire the same piece of information, they will trade aggressively. We also find that over the reform period, the median share value change of event firms is 6% higher than that of control firms. Our findings have important implications for enforcement of insider trading regulations in China.     

Insider Trading in the Hong Kong Stock Market

Many previous studies on insider trading are based ondata in the U.S. capital market and conclude thatinsiders can earn abnormal profits. This paperexamines abnormal price performance associated withinsider trading in the Hong Kong stock market. We findthat abnormal profits associated with insider tradingare all concentrated on small firms. Trading volumedoes matter in determining the magnitude of thoseabnormal profits. Our results show that insiders ofmedium-sized and large firms do not earn abnormalprofits. Finally, it is found that outsiders who mimicthe information of insider trades associated withmedium-sized and large firms cannot earn abnormalprofits.     

Stock Prices and the Secondary Dissemination of Information: The Wall Street Journal's "Insider Trading Spotlight"Column

In this paper we test whether a secondary dissemination of information affects stock prices. We examine stock price reactions to the publication of the “Insider Trading Spotlight”(ITS) column in the Wall Street Journal (WSJ). Since insider trades reported in the ITS column are initially disclosed to the public when insiders’ reports are filed with the Securities and Exchange Commission (SEC), the information contained in the WSJ is a secondary dissemination. Around the WSJ publication day, we find significant abnormal stock performance accompanied by a significant increase in trading volume. Our evidence suggests that a secondary dissemination of information can affect stock prices if the initial public disclosure attracts only limited attention by the market. In addition, we document how insider trading information is conveyed to the market.