Serial acquirers and decreasing returns: Do bidders’ acquisition patterns matter?

This paper examines the phenomenon of declining announcement returns of serial acquirers. Using a classification of acquirers based on their patterns of acquisition, I find that decreasing returns occur mostly within “blocks” of acquisitions. This trend is driven by bidders who acquire targets quickly in chunks. In contrast, I find no evidence of any such decline in returns for the most active acquirers in the market of corporate control. I test several theories proposed by the prior literature to explain declining returns and find evidence consistent with temporary overvaluation, agency costs, and bidder learning as likely drivers.