Behavioral Finance aims to explain empirical anomalies by introducing investor psychology as a determinant of asset pricing. Two kinds of anomalies, namely underreaction and overreaction, have been established by an impressive record of empirical work. While underreaction defines a slow adjustment of prices to corporate events or announcements, overreaction deals with extreme stock price reactions to previous information or past performance.

This study investigates current and past earnings surprises for listed US companies over the period 1983-1999. It provides evidence that investors exhibit long-term overreaction to past, highly unexpected, earnings surprises. Investors tend to overestimate (underestimate) future earnings after extreme positive (negative) earnings surprises. As, on average, these extreme past surprises are not confirmed by subsequent earnings figures, they are followed by a correction of the initial overreaction at the date of the subsequent earnings announcement. Moreover, the longer the similar earnings surprise series, the higher the subsequent correction, suggesting that representativeness may cause this overreaction phenomenon