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.

根据美国证券交易委员会的规定，美国公司倾向于在特定几周内公布收益，从而导致收益集中发布。我们的研究探讨了这种收益发布模式是否会导致市场反应延迟。我们观察到，与非繁忙周相比，在每个季节繁忙的两周内公布收益的公司表现出更强的收益公布后漂移（PEAD）。此外，我们发现机构投资者、金融分析师较少且规模较小的公司更容易受到市场反应不足的影响。这些发现支持反应不足在 PEAD 发生中发挥作用的假设。我们将这种反应不足的主要原因归咎于投资者及时处理大量盈利消息的能力有限。