Long Run Stock Returns after Corporate Events Revisited

Kolari, Pynnonen, and Tuncez rely on simulation outcomes to criticize the normalization of firm characteristics employed by Bessembinder and Zhang (2013) to assess returns after major corporate events. However, their simulation outcomes simply verify that a non‐linear normalization is inappropriate if the true relation is linear. The relation between log returns and firm characteristics is unknown, but is unlikely to be linear, as the distribution of firm characteristics is strongly skewed. Here, we report on bootstrap simulations that show our methods provide unbiased estimates with appropriate statistical size and high power to detect abnormal returns when implemented in actual data. Kolari, Pynnonen, and Tuncez also provide empirical estimates that comprise useful sensitivity tests. Their results verify that firm characteristics are useful in assessing whether returns to event firms are abnormal, largely confirm our conclusions with regard to SEOs, M&As, and dividend increases, but show that conclusions regarding IPOs depend on implementation choices.