Technology Transactions, Announcement Effect, and Reversal : Dissecting an Anomaly

We examine the short term stock price performance of firms that acquire or sell technology rights. We find significant positive announcement-period abnormal returns to the acquirers and sellers. However, the price increases reverse during the subsequent twenty trading days. We also find that the reversal is confined to a subsample comprised of stocks that witness pre-announcement price decline. Stocks that witness price run-up prior to the announcement do not reverse to original prices but lose the momentum right after the announcement-period. We believe this is caused by the combination effect of the momentum prior to-and the impact of the announcement