What Are the Determinants of Abnormal Returns to Bidders? An Event Study of Norwegian Bidders Listed on Oslo Stock Exchange

Abstract

We examine the abnormal returns of 158 mergers and acquisitions announced between 2001 and 2018, in which the bidder was a Norwegian firm listed on the Oslo Stock Exchange. We use an estimation window of [-147,-22] trading days and two event windows of [-5,5] and [-1,1] trading days. The results indicate that, on average, the returns to the bidding firms are significant and positive over a three day window, albeit marginally so. The returns to bidders were significant and positive between 2007 and 2012, but we attribute this to economic conjunctures and external factors. We find no evidence for relatedness increasing the abnormal returns to the bidders.