Insider trading,stock return volatility,and the option market's pricing of the information content of insider trading

We find strong evidence that net insider selling is positively associated with future stock return volatility, consistent with insider selling increasing outside investors’ uncertainty. The positive effect of net insider selling is significantly stronger when the volatility is measured around the earnings announcement. Apparently, option prices do not fully reflect the information content of insider trading for future volatility. More specifically, we find no evidence that option traders adjust the implied volatility for the insider trading effect in a timely manner. Consequently, net insider selling is significantly associated with future option straddle returns and delta neutral returns.     

Insider trading patterns

We revisit the information content of stock trading by corporate insiders with an expectation that opportunistic insiders will spread their trades over longer periods of time when they have a longer-lived informational advantage, and trade in a short window of time when their advantage is fleeting. Controlling for the duration of insiders' trading strategies, we find robust new evidence that both insiders' sales and purchases predict abnormal stock returns. In addition, we provide evidence that insiders attempt to preserve their informational advantages and increase their trading profits by disclosing their trades after the market has closed. When insiders report their trades after business hours, they are more likely to engage in longer series of trades, they trade more shares overall, and their trades are associated with larger abnormal returns. Finally, we show how accounting for these trading patterns sharpens screens for corporate insiders who trade on infor- mation.     

Insider trading and managerial incentives

We derive conditions under which permitting manager “insiders” to trade on personal account increases the equilibrium level of output and the welfare of shareholders. These increases are produced by two effects of insider trading. First, insider trading impounds information about hidden managerial actions into asset prices. This impounding of information allows shareholders to make better personal portfolio-allocation decisions. Second, allowing insider trading can induce managers to increase, on average, the correlation between their personal wealth and firm value beyond the level dictated by the employment relationship alone. This increased correlation increases managerial incentives. When these two effects are only weakly present, permitting insider trading harms shareholders, because insider trading reduces shareholder control over the performance–compensation relationship. In addition, when managerial effort incentives are high and corporate governance costs are low, managers may prefer insider-trading restrictions because such restrictions force shareholders to offer them a larger fraction of output through the employment relationship.     

Empirical study on relationship between persistence-free trading volume and stock return volatility

A large body of literature finds that the unexpected trading volume, which is obtained by filtering out time trend, autocorrelation, can be used as a proxy of the information flow and can explain the heteroskedasticity of stock return in some degrees. In this paper, we find that the heteroskedasticity exists in the unexpected trading volume, and we further generate a new information proxy by filtering out the heteroskedasticity from the unexpected trading volume, termed “persistence-free trading volume”. Our empirical results indicate that the persistence-free trading volume can explain the heteroskedasticity of the return better than the unexpected trading volume; moreover, the explanatory power of the persistence-free trading volume is positively related to market maturity.     

Insider trading and risk aversion

This paper is a continuous time version of Holden and Subrahmanyam (Economics Letters 44 (1994) 181). The paper extends Kyle (Econometrica 53 (1985) 1315) by introducing risk aversion on the side of the monopolist informed trader and allows for the liquidity traders instantaneous demand to depend on cost of trading, as well as on the risk of the stock. The main result of the paper is that, in equilibrium, the price pressure decreases with time regardless of the elasticity of the liquidity demand function.     

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 in credit derivatives

Insider trading in the credit derivatives market has become a significant concern for regulators and participants. This paper attempts to quantify the problem. Using news reflected in the stock market as a benchmark for public information, we find significant incremental information revelation in the credit default swap market under circumstances consistent with the use of non-public information by informed banks. The information revelation occurs only for negative credit news and for entities that subsequently experience adverse shocks, and increases with the number of a firm's relationship banks. We find no evidence, however, that the degree of asymmetric information adversely affects prices or liquidity in either the equity or credit markets.     

An empirical investigation of trading volume and return volatility of the Taiwan Stock Market

This study examines the Mixed Distribution Hypothesis (MDH) using 5-min interval stock returns of the Taiwan Stock Index (TSI). Startlingly enough, the persistence of stock volatility remains dominant after the stochastic mixing variable was included in the variance equation. It implies that the MDH cannot explain away the ARCH phenomenon. We have found that the composition of participants (approximately 92% of participants are individual investors) in TSI is a major contributing factor to the persistent volatility. In addition, the existence of limits on price changes, to some extent, accounts for the persistence phenomenon. Similar results are also found for individual stocks in the sample. Interestingly enough, the explanatory power of trading volume exhibits a U-shaped pattern in explaining return volatility in Taiwan Stock Market.     

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.     

Insider trading in takeover targets

We examine open market stock trades by registered insiders in about 3700 targets of takeovers announced during 1988–2006 and in a control sample of non-targets, both during an ‘informed’ and a control period. Using difference-in-differences regressions of several insider trading measures, we find no evidence that insiders increase their purchases before takeover announcements; instead, they decrease them. But while insiders reduce their purchases below normal levels, they reduce their sales even more, thus increasing their net purchases. This ‘passive’ insider trading holds for each of the five insider groups we examine, for all three measures of net purchases, and is more pronounced in certain sub-samples with less uncertainty about takeover completion, such as friendly deals, and deals with a single bidder, domestic acquirer, or less regulated target. The magnitude of the increase in the dollar value of net purchases is quite substantial, about 50% relative to their usual levels, for targets' officers and directors in the six-month pre-announcement period. Our finding of widespread profitable passive trading by target insiders during takeover negotiations points to the limits of insider trading regulation. Finally, our finding that registered insiders of target firms largely refrain from profitable active trading before takeover announcements contrasts with prior findings that insiders engage in such trading before announcements of other important corporate events, and points to the effectiveness of private over public enforcement of insider trading regulations.     

Program trading and intraday volatility

Program trading and intraday changes in the S&P 500 Indexare correlated. Futures prices and, to a lesser extent, cashprices lead program trades. Index arbitrage trades are followedby an immediate change in the cash index, which ultimately reversesslightly. No reversal follows nonarbitrage trades. The cumulativeindex changes associated with buy-and-sell trades and with arbitrageand nonarbitrage trades all are similar. Price decompositionssuggest that the results are not due to microstructure effects.Program trades in this 1989-1990 sample do not seem to havecreated major short-term liquidity problems. The results arestable within the sample.     

Insider trading with correlation between liquidity trading and a public signal

We analyse a Kyle-type continuous-time market model in which liquidity trading is correlated with a noisy public signal that is released continuously. We show that, in contrast to the previous literature, Kyle's λ, the price sensitivity to the order flow, can even be non-monotonic, depending on the correlation structure. We also show that the introduction of an additional public signal does not necessarily improve the informational efficiency of the market, depending on the correlation.     

Insider trading in rumored takeover targets

We examine insider trading surrounding takeover rumors in a sample of 1,642 publicly traded US firms. Using difference-in-differences regressions, we find that insider net purchases increase within the year prior to the first publication of a takeover rumor, particularly when rumor articles are either accurate (lead to a takeover announcement) or informative (provide substantial justification for the rumor's publication). Moreover, we find abnormal insider trading to be a significant predictor of takeover announcements occurring within the following year. Finally, passive net purchasing (i.e., selling less rather than buying more) is more pronounced among managing insiders than among non-managing insiders.     

Insider employee stock option trading and stock prices

The question of which factors determine corporate bonds pricing is investigated by analysing the spreads of eurobonds issued by major G-10 companies during the 1991–2001 period. Three main results emerge from the analysis. First, bond ratings appear as the most important determinant of yield spreads, with investors’ reliance on rating agencies judgments increasing over time. Second, the primary market efficiency and the expected secondary market liquidity are not relevant explanatory factors of spreads cross-sectional variability. Finally, rating agencies adopt a different, ‘through the cycle’, evaluation criteria of default risk with respect to the forward looking one adopted by bond investors.     

Noise trading and stock market volatility

We investigate the relative effects of fundamental and noise trading on the formation of conditional volatility. We find significant positive (negative) effects of investor sentiments on stock returns (volatilities) for both individual and institutional investors. There are greater positive effects of rational sentiments on stock returns than irrational sentiments. Conversely, there are significant (insignificant) negative effects of irrational (rational) sentiments on volatility. Also, we find asymmetric (symmetric) spillover effects of irrational (rational) bullish and bearish sentiments on the stock market. Evidence in favor of irrational sentiments is consistent with the view that investor error is a significant determinant of stock volatilities.     

Insider and liquidity trading in stock and options markets

We analyze the introduction of a nonredundant option, whichcompletes the markets, and the effects of this on informationrevelation and risk sharing. The option alters the interactionbetween liquidity and insider trading. We find that the optionmitigates the market breakdown problem created by the combinationof market incompleteness and asymmetric information. The introductionof the option has ambiguous consequences on the informationalefficiency of the market. On the one hand, by avoiding marketbreakdown, it enables trades to occur and convey information.On the other hand, the introduction of the option enlarges theset of trading strategies the insider can follow. This can makeit more difficult for the market makers to interpret the informationcontent of trades and consequently can reduce the informationalefficiency of the market. The introduction of the option alsohas an ambiguous effect on the profitability of insider trades,which can either increase or decrease depending on parametervalues.     

Corporate insider trading and return skewness

Corporate insider trades predict idiosyncratic return skewness. CEO purchases are followed by an increase and CEO sales by a decrease in idiosyncratic skewness. The evidence suggests that this effect is driven by personal preferences rather than behavioral biases such as overconfidence. Our findings are consistent with the interpretation that CEOs, who are generally considered to be underdiversified, optimize their holdings by taking their preference for positive return skewness into account. We observe particularly robust results for CEO sales, which substantiates the less common notion that insider sales can be informative for investors.     

Insider trading as a signal of private information

There is substantial evidence that insider trading is presentaround corporate announcements and that this insider tradingis motivated by private information. Using real estate investmenttrusts that choose to reappraise themselves as our sample, weestablish that the appraisals contain information, but findno market response to the public announcement of this informationin these appraisals. We consider two possible explanations forthis inconsistency: the first that the appraisal informationis not highlighted in earnings reports and hence remains unobserved;and the second that insiders trade on the appraisal informationin the time that elapses between the appraisal and its publicannouncement We find strong support for the second hypothesis,with insiders buying (selling) after they receive favorable(unfavorable) appraisal news, especially for negative appraisals.We also find that positive (negative) appraisals and net insiderbuying (selling) elicit significant positive (negative) abnormalreturns during the appraisal period     

Long memory in volatility and trading volume

We use fractionally-integrated time-series models to investigate the joint dynamics of equity trading volume and volatility. Bollerslev and Jubinski (1999) show that volume and volatility have a similar degree of fractional integration, and they argue that this evidence supports a long-run view of the mixture-of-distributions hypothesis. We examine this issue using more precise volatility estimates obtained using high-frequency returns (i.e., realized volatilities). Our results indicate that volume and volatility both display long memory, but we can reject the hypothesis that the two series share a common order of fractional integration for a fifth of the firms in our sample. Moreover, we find a strong correlation between the innovations to volume and volatility, which suggests that trading volume can be used to obtain more precise estimates of daily volatility for cases in which high-frequency returns are unavailable.     

Insider trading under trading ban regulation in China’s A-share market

This study examines the effects of China’s 2008 trading ban regulation on the insider trading of large shareholders in China’s A-share market.It finds no eviden...