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。     

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.     

Inside the <Emphasis FontCategory="SansSerif">“</Emphasis>black box<Emphasis FontCategory="SansSerif">”</Emphasis> of private in-house meetings

We examine information content and related insider trading around private in-house meetings between corporate insiders and investors and analysts. We use a hand-collected dataset of approximately 17,000 private meeting summary reports of Shenzhen Stock Exchange firms over 2012–2014. We find that these private meetings are informative and corporate insiders conducted over one-half of their stock sales (totaling $8.7 billion) around these meetings. Some insiders time their transactions and earn substantial gains by selling (purchasing) relatively more shares before bad (good) news disclosures while postponing selling (purchasing) when good (bad) news is to be disclosed in the meeting. Finally, we conduct a content analysis of published meeting summary reports and find that the tone in these reports is associated with stock market reactions around (1) private meetings themselves, (2) subsequent public release of private meeting details, (3) subsequent earnings announcements and (4) future stock performance.     

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.     

Dividends and Market Signalling: an Analysis of Corporate Insider Trading

This study tests the multiple‐signal theory of dividends of John and Lang (1991) in the context of a European market. Our evidence shows that investors are more sensitive to insider trading signals than to signalled changes in existing dividends. In effect, the insider sales signal is universally understood as bad news. After controlling for the quality of a firm's investment opportunities, investors are found to penalise dividend outflows by mature firms that exhibit more informed insider sales activity. Finally, we offer an innovative exploration of the role of earnings announcements in market reaction to the dividend signal.     

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.     

The Persistence of Opportunistic Insider Trading

We study the drivers of persistent insider trading profitability by examining the trades of insiders whose past trades have been profitable. We find that the current transactions of these persistently profitable (PP) insiders better predict firm performance than those of other insiders. The relative abnormal performance is more pronounced for trades of insiders who are managers rather than large shareholders or unaffiliated insiders and for trades in firms with weaker governance and greater information asymmetry. The trades of PP insiders also better predict earnings surprises, major corporate news, and analyst revisions. Collectively, these results indicate that PP insider transactions provide valid signals regarding future firm performance and that persistence in profitability is driven by informational advantages.     

Insider trading and shareholder investment horizons

This paper examines the effects of shareholder investment horizons on insider trading. We find that insiders are less likely to trade on private information and the profitability of insider trades is lower when shareholder investment horizons are longer. We further examine two channels through which shareholders with longer investment horizons can impede insider trading: direct monitoring and better information environment. Consistent with the direct monitoring channel, we show that insiders in firms with longer shareholder investment horizons are more likely to shift trades from the month right before earnings announcements to the month right after earnings announcements. Moreover, the impact of investment horizons are stronger in firms with higher ex ante litigation risk, with lower corporate governance quality, and that are not targets of hedge fund activists. Consistent with the information environment channel, we show that longer shareholder investment horizons increase the frequencies of information disclosure and insiders in firms with longer shareholder investment horizons are more likely to trade in an isolated manner rather than in sequences.     

Insider Trading and Voluntary Disclosures

We hypothesize that insiders strategically choose disclosure policies and the timing of their equity trades to maximize trading profits, subject to the litigation costs associated with disclosure and insider trading. Accounting for endogeneity between disclosures and trading, we find that when managers plan to purchase shares, they increase the number of bad news forecasts to reduce the purchase price. In addition, this relation is stronger for trades initiated by chief executive officers than for those initiated by other executives. Confirming this strategic behavior, we find that managers successfully time their trades around bad news forecasts, buying fewer shares beforehand and more afterwards. We do not find that managers adjust their forecasting activity when they are selling shares, consistent with higher litigation concerns associated with insider sales. Overall, our evidence suggests that insiders do exploit voluntary disclosure opportunities for personal gain, but only selectively, when litigation risk is sufficiently low.     

Management earnings forecasts,insider trading,and information asymmetry

We investigate whether senior officers use accrual-based earnings management to meet voluntary earnings disclosure (i.e., management earnings forecasts) before selling or buying their own shares when they have private information. This study is the first to use the differences in timing of trades by senior officers and other insiders (e.g., directors or large shareholders) to infer information asymmetry. We hypothesize that the timing of senior officers' trades with no other insiders' trades at the same time indicates opportunistic trades and asymmetric information between senior officers and other insiders. Our results show that senior officers' exclusive sales are negatively associated with future returns, indicating that they tend to use insider information. Moreover, senior officers are more likely to meet their earnings forecasts when they plan to sell stocks.     

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.     

Why do insiders trade? Evidence based on unique data on Swedish insiders

In this paper, we examine if corporate insiders have other motives for trading besides exploitation of private information. Our results show that insiders’ portfolio re-balancing objectives, tax considerations and behavioral biases play the most important role in their trading decisions. We also find that insiders who have allocated a great (small) proportion of their wealth to insider stock sell more (less) before bad news earnings disclosures. Finally, insider selling is informative for future returns among those insiders who have the greatest proportion of wealth allocated to insider stocks.     

Is there information content from insider trading activities preceding earnings and dividend announcements in Hong Kong?

This study examines whether insiders (directors) exploit information advantage of their firms by trading stocks before the simultaneous earnings and dividend announcements in Hong Kong. Our findings show that there are significant net-insider-buying activities before the announcements of good news ('Earnings-Dividend Increase') and significant net-insider-selling activities before bad news ('Earnings-Dividend Decrease' and 'Earnings Decrease-Dividend Zero'). In addition, our regression results provide some support for the hypothesis that there is a predictive relation between pre-event insider trading activity and the abnormal return of the announcements.     

Are trading bans effective? Exchange regulation and corporate insider transactions around earnings announcements

There is considerable controversy on the role of corporate insider trading in the financial markets. However, there appears to be a consensus view that some form of regulation concerning their activities should be imposed. One such constraint involves a trading ban in periods when corporate insiders are expected to be advantaged vis-à-vis the information flow. This paper directly tests whether constraints of this kind are effective in curtailing insider activity through a study of the trading characteristics of UK company directors. The London Stock Exchange Model Code (1977) imposes a two-month close period prior to company earnings announcements. We find that although the close period affects the timing of director trades, it is unable to affect their performance or distribution. Directors consistently earn abnormal returns irrespective of the period in which they trade. They tend to buy after abnormally bad earnings news and sell after abnormally good earnings news. Moreover, there are systematic differences in the trading patterns of directors surrounding interim and final earnings announcements. It appears that many corporate insiders have private information and exploit this in their trading activities. As a result, one can conclude that trading bans do not impose significant opportunity costs on the trading of corporate insiders.     

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.     

Insider trading in loss firms

This study investigates whether insiders in loss firms trade their company stock differentially around new loss and loss reversal earnings announcements. Research suggests that the likelihood of litigation influences managers' stock trading decisions prior to material events. I hypothesize and find that insiders reduce their net stock sales in a monotonic manner before a new loss announcement presumably to avoid improper trading allegations before bad news. This decrease is more pronounced if the new loss is the start of a multiple loss sequence. In contrast, there is no significant change in net trading patterns in the quarters prior to a loss reversal announcement irrespective of whether the loss reversal is the start of a single profit or multiple profit sequence indicating that insiders seem less concerned about legal implications when trading before good news. The results suggest that insiders in loss firms perceive asymmetric litigation risks to trading stock in the quarters before bad news relative to good news and act accordingly.     

Tone emphasis and insider trading

In this study, we examine whether emphasized tone in earnings releases systematically predict managers' insider trading activities in the post earnings releases periods and whether managers' choices of tone placement in earnings releases are motivated by opportunistic incentives. We find that, holding constant the net tone of the overall document, managers make more insider sales (purchases) immediately after earnings releases when positive (negative) tone is presented more prominently in the document. In addition, we document that the relation between tone emphasis and the observed insider trading activities is more (less) pronounced when insiders have greater information advantage or when a firm's overall information environment is more opaque (when a firm has better corporate governance). Overall, our findings suggest that managers use narrative characteristics strategically to facilitate their insider trading and achieve personal gains.     

The Relation Between Insider-Trading Restrictions and Executive Compensation

In this study I investigate the relation between firm‐level insider‐trading restrictions and executive compensation. Using a trading‐window proxy for the existence of such restrictions, I test predictions that insiders will demand compensation for these restrictions and that firms will need to increase incentives to restricted insiders. I find that firms that restrict insider trading pay a premium in total compensation relative to firms not restricting insider trading, after controlling for economic determinants of pay. Furthermore, these firms use more incentive‐based compensation and their insiders hold larger equity incentives relative to firms that do not restrict insider trading. These results hold after controlling for the endogenous decision to restrict insiders and are consistent with the notion that insider trading plays a role in rewarding and motivating executives.     

Asymmetric effects of voluntary disclosure on stock liquidity: evidence from 8‐K filings

This paper examines whether the change in stock liquidity subsequent to voluntary disclosure is different between good news and bad news. Using voluntary 8‐K filings, we find that the increase in stock liquidity is more pronounced for firms with good news disclosure than for firms with bad news disclosure. In addition, such findings are stronger when a firm is less visible and when the short‐selling costs are high, suggesting that these two factors play an important role in increasing stock liquidity. Overall, this paper provides evidence that the tone of voluntary 8‐K news is an important determinant of stock liquidity.     

What Do Management Earnings Forecasts Convey About the Macroeconomy?

We decompose quantitative management earnings forecasts into macroeconomic and firm‐specific components to determine the extent to which voluntary disclosure provided by management has macroeconomic information content. We provide evidence that the forecasts of bellwether firms, which are defined as firms in which macroeconomic news explains the greatest amount of variation in the forecasts, provide timely information to the market about the macroeconomy when bundled with earnings announcements. Further, we show that bellwether firms provide timely information about both industry‐specific events and broader economic events. Finally, we document that the macroeconomic news in individual forecasts is more pronounced for bad news and point forecasts.