A new perspective on post‐earnings‐announcement‐drift: Using a relative drift measure

Prior research finds that there is a delayed reaction to both analyst‐based earnings surprises and random‐walk‐based earnings surprises. Focusing on the market reaction from the post‐announcement window, prior studies show that analyst‐based drift is larger than random walk‐based drift. This finding is counter‐intuitive if we believe large, sophisticated investors tend to trade on analysts’ forecast earnings news and thus react faster and more completely than smaller and less sophisticated investors react to random walk earnings news. In this study, we construct a relative measure of post‐earnings‐announcement drift (PEAD) (i.e., drift as a proportion of total market reaction to earnings news) which we refer to as the ‘drift ratio’, and we provide evidence, consistent with our intuition, that analyst‐based drift ratio is smaller (not greater) than random‐walk‐based drift ratio. We find that this difference is more pronounced in more recent periods and for firms with more sophisticated investors. Our approach to measure the PEAD is more intuitive than that in traditional PEAD literature. Our results thus complement existing research findings by utilizing the drift ratio measure to generate new insights about the drift phenomenon.     

Aggregate Market Reaction to Earnings Announcements

This analysis identifies a distinct immediate announcement period negative relation between earnings announcement surprises and aggregate market returns. Such a relation implies that market participants use earnings information in forming expectations about expected aggregate discount rates and, specifically, that good earnings news is associated with a positive shock to required returns. Consistent with this interpretation we find that Treasury bond rates and implied future inflation expectations respond directly to earnings news. We also find some evidence that the negative relation between earnings news and market return persists beyond the immediate announcement period, suggesting that market participants do not immediately fully impound these future market return implications of aggregate earnings news.     

Asymmetric Trading Costs Prior to Earnings Announcements: Implications for Price Discovery and Returns

We show that the cost of trading on negative news, relative to positive news, increases before earnings announcements. Our evidence suggests that this asymmetry is due to financial intermediaries reducing their exposure to announcement risks by providing liquidity asymmetrically. This asymmetry creates a predictable upward bias in prices that increases preannouncement, and subsequently reverses, confounding short‐window announcement returns as measures of earnings news and risk premia. These findings provide an alternative explanation for asymmetric return reactions to firms' earnings news, and help explain puzzling prior evidence that announcement risk premia precede the actual announcements. Our study informs methods for research centering on earnings announcements and offers a possible explanation for patterns in returns around anticipated periods of heightened inventory risks, including alternative firm‐level, industry‐level, and macroeconomic information events.     

The Calm before the Storm

I provide evidence that stocks experiencing unusually low trading volume over the week prior to earnings announcements have more unfavorable earnings surprises. This effect is more pronounced among stocks with higher short‐selling constraints. These findings support the view that unusually low trading volume signals negative information, since, under short‐selling constraints, informed agents with bad news stay by the sidelines. Changes in visibility or risk‐based explanations are insufficient to explain the results. This evidence provides insights into why unusually low trading volume predicts price declines.     

Earnings Preannouncement Strategies

We examine the disclosure strategies managers follow when theyd preannounce quarterly earnings shortly before formal earnings announcements. We document that managers with bad news release essentially all of their news at the preannouncement date, while managers with good news only release about half of their news. Controlling for the combined news released at the preannouncement and earnings announcement dates, firms with negative earnings announcement surprises have significantly lower excess returns for the period from just before the preannouncement to just after the earnings announcement. This finding is consistent with the observed disclosure strategies whereby managers attempt to avoid negative earnings announcement surprises, and suggests that how information is presented can affect the market's reaction to that information.     

Informed trading in public debt markets

This study examines the occurrence of informed trading in public debt issued by companies in the United States. I find that earnings surprises are positively associated with bond price changes prior to the release of financial report data to the public, for firms with non‐investment‐grade ratings. Additionally, I find that the effect appears to be driven by firms with publicly traded equity. Evidence further indicates an increase in trading activity during the time window between report period end date and filing date, for firms with larger earnings surprises.     

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.     

Informed trading before positive vs. negative earnings surprises

This paper investigates whether institutional investors trade profitably around the announcements of positive or negative earnings surprises. Using Korean data over the period of 2001–2010, we find that information asymmetry is larger before negative earnings surprises (earnings shock) among investors and that the trading volume decreases only before earnings shock announcements due to the severe information asymmetry. We also find that institutions sell their stocks prior to earnings shock announcements whereas individual and foreign investors do not anticipate bad news. Finally, we find that institutional trade imbalance is positively related to the post-announcement abnormal returns of negative events. This study complements and extends prior literature on informed trading around earnings announcements by documenting evidence that domestic institutions exploit their superior information around particularly earnings shock announcements.     

The effect of the summer doldrums on the market reaction to earnings announcements

Hong and Yu (2009) document a significant decrease in trading volume and returns during the summer months. Given the tendency of noise traders to buy shares following both positive and negative earnings surprises (Lee, 1992), we hypothesize that reduced trading activity by noise-traders results in less of an earnings announcement premium during the summer. Consistent with our hypothesis, we find lower abnormal returns surrounding summer earnings announcements compared to non-summer announcements. We also find lower abnormal returns in the ten days prior to the announcement, consistent with less front-running by sophisticated investors. Finally, we show that these summer effects are stronger in recent years characterized by more online trading and greater noise trader participation.     

The Impact of Regulation Fair Disclosure on Information Asymmetry and Trading: An Intraday Analysis

This study examines the impact of Regulation Fair Disclosure (FD) on liquidity, information asymmetry, and institutional and retail investors trading behavior. Our main findings suggest three conclusions. First, Regulation FD has been effective in improving liquidity and in decreasing the level of information asymmetry. Second, retail trading activity increases dramatically after earnings announcements but there is a significant decline in institutional trading surrounding earnings announcements, particularly in the pre‐announcement period. Last, the decline in information asymmetry around earnings announcements is closely associated with a lower participation rate in the pre‐announcement period and more active trading of retail investors after earnings releases.     

Market Sidedness: Insights into Motives for Trade Initiation

We infer motives for trade initiation from market sidedness. We define trading as more two-sided (one-sided) if the correlation between the number of buyer- and seller-initiated trades increases (decreases), and assess changes in sidedness (relative to a control sample) around events that identify trade initiators. Consistent with asymmetric information, trading is more one-sided before merger news. Consistent with belief heterogeneity, trading is more two-sided before earnings and macro announcements with greater dispersion in analyst forecasts, and after news with larger announcement surprises. We examine the codeterminacy of sidedness, bid-ask spread, volatility, number of trades, and order imbalance.     

The options market response to accounting earnings announcements

We examine the reaction of the equity options market to accounting earnings announcements over the period 1996–2008 using changes in implied volatility to measure the options market response to earnings news. We find that positive earnings surprises and positive profit announcements produce a larger uncertainty resolution than negative earnings surprises and loss announcements. We demonstrate an inverse relation between the change in implied volatility and earnings news in a three-day window immediately after an earnings announcement. We refer to the magnitude of this relation as the ‘options market earnings response coefficient’. This ‘options market earnings response coefficient’ is stronger for both bad news announcements and positive profit announcements. We do not find any significant relation between changes in implied volatility and earnings news in the pre- or post-announcement periods. We conclude that the options market efficiently absorbs earnings information.     

Short-Selling Prior to Earnings Announcements

This paper examines short‐sales transactions in the five days prior to earnings announcements of 913 Nasdaq‐listed firms. The tests provide evidence of informed trading in pre‐announcement short‐selling because they reveal that abnormal short‐selling is significantly linked to post‐announcement stock returns. Also, the tests indicate that short‐sellers typically are more active in stocks with low book‐to‐market valuations or low SUEs. The levels of pre‐announcement short‐selling, however, mostly appear to reflect firm‐specific information rather than these fundamental financial characteristics. We believe that these results should encourage financial market regulators to consider providing more extensive and timely disclosures of short‐selling to investors.     

Individual Investor Trading and Return Patterns around Earnings Announcements

This paper provides evidence of informed trading by individual investors around earnings announcements using a unique data set of NYSE stocks. We show that intense aggregate individual investor buying (selling) predicts large positive (negative) abnormal returns on and after earnings announcement dates. We decompose abnormal returns following the event into information and liquidity provision components, and show that about half of the returns can be attributed to private information. We also find that individuals trade in both return‐contrarian and news‐contrarian manners after earnings announcements. The latter behavior has the potential to slow the adjustment of prices to earnings news.     

Earnings shocks,price responses,and short selling behavior

Existing researches usually study short sellers' behavior along a single dimension such as earnings news without considering the implications of multiple signals. In this paper, we investigate short selling behavior at earnings announcement period by using the shorting data from the Regulation SHO pilot program for the period January 2005 to July 2007. First, we document that, in about one third of our sample, earnings surprises and corresponding market price changes have opposite signs. By investigating how short sellers trade when earnings shocks and market price responses are of opposite signs, we find that there are more short selling activities when the market responds positively to negative earnings surprises; and that there are fewer short selling activities when the market responds negatively to positive earnings surprises. Overall, the shorting intensity at announcement period depends on both the earnings shock and price response signals.     

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.     

Unsophisticated Arbitrageurs and Market Efficiency: Overreacting to a History of Underreaction?

Prior research has documented that arbitrage activity significantly reduces or eliminates stock market anomalies. However, if anomalies arise due to unsophisticated investors’ behavioral biases, then these same biases can also apply to unsophisticated arbitrageurs and thereby disrupt the arbitrage process. Consistent with a disruption in the arbitrage process for the post‐earnings announcement drift anomaly, I document that the historically positive autocorrelation in firms’ earnings announcement news has become significantly negative for firms with active exchange‐traded options. For these easy‐to‐arbitrage firms, the firms in the highest decile of prior earnings announcement abnormal return (prior earnings surprise), on average, underperform the firms in the lowest decile by 1.59% (1.43%) at their next earnings announcement. Additional analyses are consistent with investors learning about the post‐earnings announcement drift anomaly and overcompensating. This study suggests that unsophisticated attempts to profit from a well‐known anomaly can significantly reverse a previously documented stock return pattern.     

Insider trading and response to earnings announcements: the impact of accelerated disclosure requirements

This paper contributes to the debate on the consequences of increased disclosure regulation by investigating the effects of expedited reporting requirements of Form 4 filings, mandated by the Sarbanes–Oxley Act (SOX), on the market response to earnings announcements. We first confirm that SOX reduces opportunistic insider trading without deterring insider trading due to diversification needs, and that post-SOX, opportunistic insider trades more strongly reveal upcoming earnings surprises. We then document that, at the earnings announcement date, earnings response coefficients (ERCs) are lower when earnings are preceded by opportunistic insider trades. We conclude that accelerated disclosures of insider transactions mandated by SOX lend to more informationally efficient prices prior to earnings announcements. Our findings stand as one piece of evidence suggesting positive externalities from recent Securities and Exchange Commission (SEC) disclosure regulation and add to the scarce evidence on the consequences of changes in Form 4 filing requirements.     

Information of Unusual Trading Volume

This article investigates the information content of stock unusual trading volume from the aspect of firm fundamental information revealed by both earnings formal announcements and preannouncements. By using the stock market data of China from the second quarter of 2003 to the end of 2015, this article provides evidence that, in general, stocks that experience unusually low trading volume over the week prior to earnings announcements have more unfavorable earnings surprises. However, because of the feature of mandatory pre-disclosure policy in China, this article further finds that the relation between unusually low trading volume and unfavorable earnings surprises only exists in the stocks without earnings preannouncements, because fundamental information is incorporated in the stock prices timely around preannouncements date. In addition, unusually low trading volume signals negative fundamental changes revealed by preannouncements, and this effect is more pronounced among stocks with higher short-selling constraints, but unusually high trading volume is value-irrelevant.     

Earnings characteristics and analysts’ differential interpretation of earnings announcements: An empirical analysis

This study provides empirical evidence on factors that drive differential interpretation of earnings announcements. We document that Kandel and Pearson's forecast measures of differential interpretation are decreasing in proxies for earnings quality and pre‐announcement information quality. This evidence yields new and useful insights regarding which earnings announcements are less likely to generate newfound disagreement among analysts and investors. Recent research suggests that investor disagreement can increase investment risk, increase the cost of capital, and cause stock prices to deviate from fundamental value. Therefore, our results support prior intuition that increasing the quality of earnings and pre‐announcement information can improve the efficiency of capital markets.