Earnings surprise measures the gap between what analysts expected a company to report and what it actually reported, expressed as a percentage above or below the consensus EPS estimate. Positive surprises — where actual EPS beats the consensus — are associated with post-announcement price gains, and research shows that the magnitude of the initial reaction often correlates with the surprise size. However, the stock's subsequent behavior depends heavily on the quality of the beat: a company that beats by exceeding revenue expectations and raising forward guidance is more durable than one that beats because of favorable one-time items or below-the-line cost cuts. Analyst estimates are often managed downward through the quarter by company guidance, creating an artificially easy bar to clear — this is why consistently meeting expectations with no genuine beat is sometimes labeled a "whisper miss." Large negative earnings surprises tend to generate more severe price reactions than equivalent positive surprises produce gains, reflecting the asymmetric nature of investor loss aversion.
