Many physician practices may involve firms that compete closely enough to raise antitrust concerns, according to a 2025 analysis of claims data covering more than 60 million insured members a year.
The analysis, conducted by Federal Trade Commission researchers, was published in May in Health Affairs Scholars. It identified 2,019 physician practice mergers between 2015 and 2020 using data from six insurers across 15 states, covering up to 63 million members each year.
Here are seven things to to know:
1. Deal volume remained relatively steady throughout the study period, with 318 mergers in 2015, 323 in 2016, 355 in 2017, 372 in 2018 and 377 in 2019. The total dropped to 274 mergers in 2020, which the researchers attributed to a lack of data available for 2021 that would capture fourth-quarter activity.
2. The study found consolidation extended well beyond isolated transactions. About 20% of the 15,000 physician firms in the dataset were involved in a merger during the study window.
3. On the physician level, consolidation touched a substantial share of physicians. Between 2015 and 2020, 38% of physicians worked for a firm that acquired at least one practice, and 3.8% worked for a firm that was acquired.
4. The analysis found 40% of physician practice mergers involved a health system, and health system-linked overlaps accounted for 43% of all same-specialty merger overlaps.
5. The scale imbalance between buyers and sellers was pronounced. Acquiring organizations averaged 232 physicians (median 53) compared to nine physicians at acquired practices (median five). The financial gap was similarly wide: Acquiring firms reported mean revenue of $70 million (median $21 million) versus mean revenue of $4.3 million (median $1.8 million) for acquired firms.
6. To assess whether these mergers could reduce competition, researchers evaluated 2,184 same-specialty overlaps and measured “diversion ratios,” a standard indicator of how strongly patients might shift from one firm to the other. “Diversion ratios were calculated using commercial (employer-sponsored + individual) claims only. Higher diversion ratios indicate that the practices were closer substitutes before the merger. Across same-specialty overlaps, 20% had diversion ratios above 15%, signaling that the merging practices were close competitors. Over half had diversion ratios below 5%.”
7. Health system-linked deals tended to involve higher diversion ratios than non-system deals, suggesting system acquisitions may more often combine providers in competitive proximity, the study noted.
