The Insignificance of Clear-Day Poison Pills

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Exploiting a hand-collected database with almost 2,200 firms during 1996–2014, I analyze the relationship between the presence of poison pills and firm value. Consistent with earlier results, I document a strong negative association between pills and firm value cross-sectionally and within firm. However, I document that all the within-firm association is driven by pill adoptions (and none by the dropping of pills), all the drop in value associated with adoptions precedes the pills’ adoption, and firms adopted their pills after experiencing drops in their operating performance. These results indicate that the ostensive negative effect of pills on firm value is due to a spurious correlation and that prior analyses were incorrect in concluding that pill adoptions are harmful and indicative of bad governance. Moreover, the results question the usefulness of the dramatic drop in the incidence of pills that took place during the last decade.

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