A growing narrative has arisen that antitrust regulators have systematically relaxed enforcement over time. This narrative has led to calls for reinvigorated enforcement and the passage of new tougher antitrust legislation. In this paper, we employ data drawn directly from the antitrust agencies to examine this claim. Data collected from 1979 to 2017 indicate that, contrary to the popular narrative, regulators have become more likely to challenge proposed mergers over time. Controlling for the number of merger proposals submitted to the agencies, the likelihood of a merger challenge has more than doubled over this period. After remaining relatively constant over previous administrations, merger enforcement intensity (MEI) rose in the G.W. Bush and even more so in the Obama administrations. The data also reveal that MEI is positively influenced by the agency budget size. Were historical enforcement tendencies to continue, a ten percent increase in the agencies’ budgets would yield an eight percent increase in merger challenges. This finding suggests that, independent of any statutory changes to existing antitrust laws, variation in agency budgets provides a viable pathway to enhanced merger enforcement.

中文翻译：

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合并执法强度的演变：数据显示了什么？

越来越多的人认为，随着时间的推移，反垄断监管机构已经系统地放松了执法。这种叙述导致呼吁重振执法和通过新的更严格的反垄断立法。在本文中，我们使用直接从反垄断机构获取的数据来检验这一主张。从 1979 年到 2017 年收集的数据表明，与流行的说法相反，随着时间的推移，监管机构更有可能挑战拟议的合并。控制提交给机构的合并提案的数量，在此期间合并挑战的可能性增加了一倍多。在与前几届政府保持相对稳定之后，GW Bush 政府的兼并执法强度 (MEI) 有所上升，而奥巴马政府的情况更是如此。数据还显示，MEI 受到机构预算规模的积极影响。如果历史执法趋势继续下去，机构预算增加 10% 将导致合并挑战增加 8%。这一发现表明，独立于现有反垄断法的任何法定变更，机构预算的变化为加强合并执法提供了可行的途径。