Herding on Earnings News : The Role of Institutional Investors in Post-Earnings-Announcement Drift

We examine the role of institutional investors underlying post-earnings-announcement drift (PEAD). Our results show that while institutional investors generally herd on earnings news, such correlated trading among institutions does not eliminate or reduce market underreaction to earnings surprises. Instead, PEAD is significant only in the subsample of stocks where institutions herd in the same direction as earnings surprises. In fact, institutional herding is also positively related to next-quarter earnings announcement returns. We provide evidence that institutional herding on or against earnings news is largely driven by firm characteristics, particularly past firm performance and stock returns. In addition, we find that relative to non-transient institutions, transient institutions have a stronger tendency to herd on earnings information. Finally, based on long-run stock returns, we show that when institutions herd on earnings surprises, institutional trading represents a gradual process of incorporating information into stock prices. On the other hand, when institutions herd against earnings surprises, institutional trading slows down stock price discovery