Seasonal patterns of earnings releases and post-earnings announcement drift

In line with SEC regulations, U.S. firms tend to announce their earnings in specific weeks, resulting in clustered earnings releases. Our study examines whether this pattern of earnings releases leads to delayed market responses. We observe that firms announcing earnings in the two busy weeks of each season exhibit a stronger post-earnings announcement drift (PEAD) compared to those in non-busy weeks. Additionally, we find that firms with fewer institutional investors, financial analysts, and smaller sizes are more susceptible to market under-reaction. These findings support the hypothesis that under-reaction plays a role in the occurrence of PEAD. We attribute this under-reaction mainly to investors' limited capacity to promptly process a large volume of earnings news simultaneously.