The Effects of Antitrust Laws on Horizontal Mergers: International Evidence
研究20个国家竞争法分阶段实施如何影响横向并购结果，发现反垄断法规降低了收购方公告前后的累计异常收益，支持市场势力假说，并指出反垄断执法估计存在向下偏差。
Abstract This study examines how antitrust law adoptions affect horizontal merger and acquisition outcomes. Using the staggered introduction of competition laws in 20 countries, we find antitrust regulation decreases acquirers’ 5-day cumulative abnormal returns surrounding horizontal merger announcements. A decrease in deal value, target book assets, and industry peers’ announcement returns are consistent with the market power hypothesis. Exploiting antitrust law adoptions addresses a downward bias to an estimated effect of antitrust enforcement. The potential bias from heterogeneous treatment effects does not nullify our results. Overall, antitrust policies seem to deter post-merger monopolistic gains, potentially improving customer welfare.