# Analysis of Informed Trading in Earnings Announcements A study revealing how market participants trade using private information. - **Source:** [Journal of Accounting Research](https://onlinelibrary.wiley.com/journal/1475679x) - **Published:** 2026-07-23 - **Topic:** [Finance](https://brifing.si/c/finance) - **Original article:** - **On Brifing:** https://brifing.si/s/4926e8a6-c902-470e-ba0d-92ec532a23bf ## Introduction This study examines how market participants use private information about firm fundamentals. Between 2011-2015, a cartel illegally accessed and traded on over 1,000 earnings announcements. This scenario provides a unique opportunity to understand the dynamics of informed trading. ## Preferences of Informed Traders The research shows that informed traders preferred announcements with large earnings and sales surprises relative to forecasts. Quantitative managerial guidance and extreme news sentiment also attracted their interest. These factors stood out as the most price-relevant information. ## Performance Expectations Despite perfect foresight, informed traders surprisingly underperformed. This was due to frictions like price impact, risk aversion, and information processing costs. Their returns fell far below theoretically possible gains. ## Market Dynamics The study reveals that firm fundamentals explain little of the cross-sectional variation in earnings announcement returns. Even for sophisticated participants, this information fails to fully capture expected returns. ## Legal and Ethical Issues The cartel's illegal activities posed serious threats to market integrity. Early access to information created unfair advantages, undermining market trust. This highlights the need for stronger regulatory measures. ## Conclusion and Recommendations The research outlines the limits of informed trading and its impact on market efficiency. Regulators must develop policies to reduce information asymmetry and enhance transparency. These findings offer key insights for investors and policymakers. ## Sources covering this story - https://onlinelibrary.wiley.com/doi/10.1111/1475-679x.70032?af=R — --- _Summary written by Brifing from the original reporting. Copyright in the original article belongs to its publisher; read the full piece at the link above._