Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
This article analyses how horizontal mergers affect innovation of the merged entity and its non-merging competitors. Using data on horizontal mergers among pharmaceutical firms in Europe and applying propensity score matching estimators, we find that average patenting and R&D of the merged entity and its rivals declines substantially in post-merger periods. We show that this result is consistent with the predictions from an oligopoly model with heterogeneous firms, as well as a patent race model, when pre-merger R&D intensity is sufficiently high. Consistent with our theoretical model, we find that negative effects of mergers on innovation are concentrated in markets with high R&D intensity and in technology classes with overlap in pre-merger innovation activities of merging and rival firms.