Further Evidence on Long-Run Abnormal Returns after Corporate Events Using Standardized Tests

August 2021 | Kolari, James W.

This paper investigates abnormal standardized returns (ASRs) after major corporate events. Dutta, Knif, Kolari, and Pynnonen (2018) have shown that the ASR t-test has superior size and power compared to traditional test statistics. Based on this new test statistic compared to traditional test methods, we re-examine long-run abnormal returns after mergers and acquisitions, initial public offerings, seasoned equity offerings,
dividend initiations, stock repurchases, stock splits, and reverse stock splits. While some recent studies report disappearing long-run event effects over time, our ASR tests in different subperiods from 1980 to 2015 detect significant long-run abnormal returns after these corporate actions. Graphical analyses of ASRs further support our statistical test results. We conclude that long-run abnormal returns persist after major corporate



  • James W. Kolari
  • Seppo Pynnonen
  • Ahmet M. Tuncez


Quarterly Review of Economics and Finance