The Trump Administration has signaled its intention to continue reliance on the 2023 US Merger Guidelines. One important change in the Guidelines relative to their 2010 predecessor is the switch to a stronger structural presumption of anti-competitive harm. So, the question arises: does the new structural presumption improve the ability of US antitrust agencies to distinguish anti-competitive and benign mergers? In “The Structural Presumption in the 2023 US Merger Guidelines,” Senior Consultant Matt Wohlleben and his co-author Davide Bernardini (AlixPartners) address this question.
Using simulated merger data, Mr. Wohlleben and Mr. Bernardini find that the 2023 Guidelines may significantly increase the number of mergers flagged for review, reducing the false-negative rate but dramatically raising the false-positive rate. They demonstrate that a stricter structural presumption does not appear to enhance the detection of coordinated effects, and that many newly screened mergers are unlikely to cause substantial unilateral price effects. The authors suggest that alternative presumptions based solely on changes in the Herfindahl–Hirschman Index (not the level) may outperform the 2023 Guidelines in detecting unilateral price effects.
