信息披露与内部人股票交易获利策略——以六起内部人股票交易为基础的案例研究

本文以近期A股市场内部人股票交易活跃的六家公司为例,通过考查信息披露与内部人股票交易间的关系,解释内部人股票交易的获利策略。研究发现,在允许内部人交易本公司股票的情况下,信息披露与内部人股票交易关系密切,内部人存在利用私有信息和策略性信息披露两类获利策略。信息权力是内部人股票交易的获利基础,公司业绩是影响内部人股票交易获利策略选择的重要因素,而法律诉讼风险并没有对我国内部人股票交易和信息披露产生明显约束作用。这些发现对完善我国资本市场内部人股票交易行为规范具有一定借鉴意义。     

重大事件披露、股价异常波动与内幕交易——基于重大信息披露违规公司的经验证据

规范化的信息披露是证券市场正常运转的基石。本文利用重大事件披露违规公司研究信息披露违规背后是否存在股价异常波动与内幕交易现象，并将样本公司按照处分类型和公司类型分类检验。研究表明，总体样本公司的股票存在显著的内幕交易行为，并呈现出牛市背景下的新特征：受到公开谴责的公司股票内幕交易程度显著高于受到公开处罚的公司股票，ST公司股票的内幕交易程度显著高于非ST公司股票。     

Insider trading and performance of seasoned equity offering firms after controlling for exogenous trading needs

Insiders trade not only because they have private information about their companies but also because of other exogenous reasons. Therefore, it is important to control for exogenous trading needs in empirical studies regarding insider trading. Lee (1997) shows that insider trading is not closely related to the long-term performance of primary seasoned equity offering firms. This paper examines whether the results hold after controlling for exogenous needs to trade by using an inequality test with instrumental-variables technique.     

业绩预告下的股份减持与内幕交易——会计稳健性是遏制还是助力？

选取2010—2018年沪深A股上市公司为样本,考察业绩预告发布前后大股东是否存在以及如何利用自身信息优势进行股份减持交易,会计稳健性是否以及如何对该内幕交易产生影响。研究结果表明:与强制性业绩预告相比,自愿性业绩预告披露前后发生大股东减持的概率更高,并且会计稳健性会显著抑制自愿性业绩预告披露前后的大股东减持行为。进一步将业绩预告消息区分为好消息和坏消息之后研究发现:坏消息的利空程度越高,大股东在业绩预告之前进行股份减持的规模越大;或者好消息的利好程度越高,大股东在业绩预告之后减持的规模也越大;稳健的财务信息能够抑制公司在隐匿坏消息方面进行的内幕交易,但会加剧公司在隐匿好消息方面进行的内幕交易。     

Insider,outsider and information heterogeneity

In financial markets, although the insider has superior information relative to the outsider, the outsider may possess some information the insider can’t precisely observe. This work investigates the impacts of information heterogeneity between the insider and outsider based on Foster and Viswanathan (1994). It shows that the less the insider knows about the outsider, the more she commits to aggressive trading, enabling her to earn more at the cost of outsider’s losses. Meanwhile, information heterogeneity improves the liquidity and benefits noise traders.     

Insider trading in a two-tier real market structure model

This paper investigates the real and financial effects of insider trading in the spirit of Jain and Mirman (2000). Unlike the existing literature, the production of one real good is costly and depends mainly on the price of an intermediate good produced locally by a privately owned firm. The results show that the output level of the final good chosen by the insider as well as the price of the intermediate good set by the privately owned firm are both higher than it would be in the absence of insider trading. Furthermore, the parameters of both real markets affect the stock price. Next, a second insider, operating in the firm producing the final good, is added to the benchmark model. Competition among insiders decreases the production of the final good by the publicly owned firm and the price of the intermediate good with respect to the benchmark model. Moreover, it affects the insiders’ trades and increases the amount of information revealed in the stock price.     

Option introduction and insider trading in the NASDAQ/NMS equity market

This paper investigates and supports the hypothesis that insiders have an incentive to shift their informed trading activities when options initially are listed for a firm. Firm size is found to be related to the level of insider trading activity. There is a significant decrease in insider equity-market volume for the smallest third of firms, a significant increase in insider-equity market volume for the middle third of firms, and a significant decrease in insider equity-market volume for the largest third of firms. This supports the hypothesis of a difference in the degree of impact on equity volume upon option introduction based upon firm size. This research provides additional evidence of informed trading activities when option introduction, insider trading, and firm size are considered simultaneously.     

Do Managers Trade on Public or Private Information? Evidence from Fundamental Valuations

Using accounting-based (residual income) valuations, this study examines the extent to which abnormal returns after insider share trades are explained by private information versus mispricing of public information. For a sample of insider trades in the Netherlands (1999–2008), I find that managers' share purchase decisions are associated with positive future abnormal returns as well as equity undervaluation. Even though undervaluation results in predictable price increases, positive abnormal returns following purchases persist after controlling for fundamental valuations. Thus, this study provides evidence on the sources of managers' personal trading gains and suggests that positive abnormal returns after insider share purchases reflect both private information and managers' responses to market mispricing of public information.     

控制权转移中内幕交易严重程度研究

本文在对内幕交易识别研究的文献进行系统梳理的基础上,测算了中国控制权转移事件（2001~2009年）中的内幕交易严重程度,并且利用回归模型研究了控制权转移中内幕交易严重程度的影响因素。研究发现,控制权转移事件的内幕交易效应超过50%,公告效应仅为19.1%,即80.9%的超额收益发生在控制权转移事件首次公告日之前,可以看出控制权转移过程中的内幕交易相当严重;流通市值规模、股价波动幅度、目标公司的盈利性、公司治理水平等都对内幕交易的严重性有显著影响。     

Risk aversion,public disclosure,and partially informed outsiders

In this paper, we examine the impact of public disclosure and partially informed outsiders on a risk-averse insider’s trading behavior, market efficiency, and market depth. In our model, under disclosure requirements, except for the final auction, market depth is the same at every auction. When informed outsiders are risk-neutral, in contrast to the case of a risk-averse insider with no informed outsiders, the insider is more concerned about the uncertainty about future price risk. When the number of informed outsiders increases, market liquidity improves, and the insider increases the variance of her random component to conceal her trading strategy. However, since the insider is relatively more risk-averse, she pays less attention to doing this on her own. Besides, the order flow provided by informed outsiders and randomly added by the insider injects additional liquidity into the market. When informed outsiders are risk-averse, compared to risk-neutral informed outsiders, an insider is most concerned about trading risks brought by informed outsiders at the beginning of trading. Furthermore, whether the trader is an insider or informed outsider, the more risk-averse trader has lower expected profits. Moreover, outsiders’ greater risk aversion leads to a smaller market depth.     

Insider Trading, Earnings Management and Corporate Governance: Empirical Evidence Based on Hong Kong Firms

We document positive association between earnings management and insider selling after the fiscal year‐end for Hong Kong firms. This positive association is especially evident before the 1997 Asian Financial Crisis. Our findings suggest that Hong Kong executives manage reported earnings to maximize their private benefits from insider selling. Additionally, we find that a higher proportion of independent directors (INED) on corporate boards moderate the positive association between insider selling and earnings management. Stricter monitoring of earnings management by INED is especially evident when no member of the family with majority ownership is present on corporate boards as a director. This suggests that the presence of family members with majority ownership on corporate boards significantly reduces INED's monitoring effectiveness. Our findings suggest that strict regulations are needed to control insider trading, and independence of corporate boards is important for monitoring of earnings management associated with insider trading. Furthermore, appointment of family members with majority shareholdings should be avoided to enhance independence and to monitor effectiveness of corporate boards.     

Experimental evidence on trading behavior,market efficiency and price formation in double auctions with unknown trading duration

The reasons for the highly efficient market outcomes observed under the double auction remain unclear. This paper presents a series of experimental financial markets designed to investigate the importance of unknown trading period duration on trading behavior and the convergence tendencies of such markets. Using panel data techniques the results support the conclusions that individuals generally display more aggressive trading strategies, trading earlier in a period, and that markets exhibit reduced levels of informational efficiency when unknown duration is present. Markets with imperfect information structures are also studied and, in a unique result, are associated with significantly slower rates of trade, as traders become more cautious over their trading strategies. Investigation of the price formation process provides evidence that the pricing error varies over time and the estimation of a fixed effects model provides unique support that learning effects and unknown trading period duration influence the price formation process. Future refinement of theoretical models of the price formation process or institutions of exchange should recognize the effect of unknown trading period duration on market behavior, along with potential learning effects. Copyright © 2005 John Wiley & Sons, Ltd.     

The joint decision to manage earnings through discretionary accruals and asset sales around insider trading: Taiwan evidence

This study assesses the joint decision of multiple earnings–management tools around insider trading. The Taiwanese evidence indicates significantly higher magnitudes of both discretionary accruals and asset sales before insider selling. In addition, to investigate the endogenous relationship between discretionary accruals and asset sales, this study develops a set of simultaneous equations and includes the inverse Mill’s ratio as a regressor to account for firms that choose not to use asset sales. The results indicate a marginal complementary correlation between discretionary accruals and asset sales before insider selling. Further tests find this complementary correlation becomes stronger when accompanying abnormal insider selling. The findings support the view that insiders consider both tools jointly and adjust them as complements to meet their directional earnings management objective.     

Competitive market equilibrium under asymmetric information

This paper studies the existence of a competitive market equilibrium under asymmetric information. There are two agents involved in the trading of the risky assets: an “informed” trader and an “ordinary” trader. The market is competitive and the ordinary agent can infer the insider information from the price dynamics of the risky assets. The insider information is considered to be the total supply of the risky assets. The definition of market equilibrium is based on the law of supply-demand as described by a rational expectations equilibrium of the Grossman and Stiglitz (Am Econ Rev 70:393–408, 1980) model. We show that equilibrium can be attained by linear dynamics of an admissible price process of the risky assets for a given linear supply dynamics.      

Insider trading around open-market share repurchases

We examine insider trading around open-market share repurchases and find that insiders trade passively in 3 months prior to repurchase announcements and in up to 12 months following the announcements. Furthermore, both pre-announcement and post-announcement abnormal insider trading is unrelated to short-term announcement returns but correlated with long-term post-announcement returns. Our results indicate that corporate insiders trade passively around repurchase announcements in accordance with their perceived undervaluation to exploit the long-run abnormal stock returns related to the events.     

公司治理、信息披露质量与知情交易

通过对公司治理、信息披露质量与知情交易之间关系的检验,发现股权集中导致的协同效应及壕沟效应同时存在,董事会规模及独立性对信息披露质量及知情交易的影响不明显,高管货币薪酬激励手段比股权激励手段更有效。研究表明,在当前我国资本市场不完善、知情交易日益增多的背景下,努力提高信息披露质量、实现股权适度分散以及合理制定高管薪酬契约对减少知情交易、维护资本市场的良好秩序具有重要意义。     

Reputation, Honesty, and Efficiency with Insider Information: an Experiment

We conduct an experimental study of sales of insider information about an asset's future value, where the insiders cannot purchase the underlying asset. We examine whether such information is purchased, the quality of the information provided, and the subsequent accuracy of purchase decisions in the underlying asset market. Our design explores whether reputation, in a repeated game of finite (but uncertain) duration, is an effective constraint on deliberate strategic misinformation. The insiders have an immediate incentive to state that the asset value is high when its true value is low. We suggest an application to insider trading in financial information markets. With fixed matching, cooperative outcomes featuring truthful revelation are frequently achieved and sustained, even though this suggests subjects have sophisticated beliefs about the beliefs and behavior of others. As a comparison, we also conduct a control treatment with random rematching. Here, information purchase is less frequent, the rate of truthful revelation decreases, and efficiency is diminished. Our results suggest that most people anticipate that others realize the potential value of a good reputation.     

Cournot duopoly and insider trading with two insiders

We study the effect of competition among insiders in an extension of the static Kyle [Kyle, A. (1985). Continuous auctions and insider trading. Econometrica, 53, 1315–1335] model of insider trading introduced by Jain and Mirman (JMC) [Jain, N., & Mirman, L.J. (2002). Effects of insider trading under different market structures. The Quarterly Review of Economics and Finance, 42, 19–39]. In the JMC model competition in the real sector is introduced. In this paper we introduce competition in the stock sector in the JMC model by assuming that there is a manager who is responsible for making the real decisions of the firm as well as an ‘owner’ who has the same information as the manager but has no managerial responsibilities. In this way we can study the interaction between competition in the real sector and competition in the financial sector. We show that the stock price set by the market makers reveals more information than in the JMC model and that the expected equilibrium values of the manager’s profits sometimes decline and sometimes increase depending on the exogenous parameters of the model. Moreover, we prove that due to the competition in the financial sector, the level of output produced by the firm is less than in JMC. Finally, we also study the effect of financial competition in the case in which the market makers receive only one signal and analyze the comparative statics in this case.     

Suppressing Insider Trading

Writing in Economic Affairs, Vol. 7, No. 5, Hugh High, Professor of Accounting and Finance at Massey University, New Zealand, argued that attempts to suppress insider trading would both impede the workings of the market and trample basic individual liberties. Edgar Palamountain, Director of the Esmee Fairbairn Charitable Trust, takes issue with Hugh High: insider trading, he claims, is not victimless and should be outlawed by statutory sanction. Hugh High defends his corner.     

An equilibrium model of insider trading in continuous time

We study a Bayesian–Nash equilibrium model of insider trading in continuous time. The supply of the risky asset is assumed to be stochastic. This supply can be interpreted as noise from nonrational traders (noise traders). A rational informed investor (the insider) has private information on the growth rate of the dividend flow rewarded by the risky asset. She is risk averse and maximizes her inter-temporal utility rate over an infinite time-horizon. The market is cleared by a risk neutral market maker who sets the price of the risky asset competitively as the conditional present value of future dividends, given the information supplied by the dividend history and the cumulative order flow. Due to the presence of noise traders, the market demand does not fully reveal the insider’s private information, which slowly becomes incorporated in prices. An interesting result of the paper is that a nonstandard linear filtering procedure gives an a priori form for the equilibrium strategy to be postulated. We show the existence of a stationary linear equilibrium where the insider acts strategically by taking advantage of the camouflage provided by the noise which affects the market maker’s estimates on private information. In this equilibrium, we find that the insider’s returns on the stock are uncorrelated over long periods of time. Finally, we show that the instantaneous variance of the price under asymmetric information lies between the instantaneous variance of the price under complete and incomplete information. The converse inequalities hold true for the unconditional variance of the price.