Over an eight-year span, the number of physicians employed by hospitals nearly doubled, and that shift has come at a cost, according to a recent study.
Published in July 2025 by the National Bureau of Economic Research, the study analyzed hospital acquisitions of physician practices between 2008 and 2016. Using machine learning algorithms, researchers identified a broad range of integration events across various market conditions. They then linked these acquisitions to claims data from a large national insurer to examine the impact on healthcare pricing.
Here are 10 key findings from the study and related surveys:
1. Hospital acquisitions surged. The share of private physician practices acquired by hospitals rose by 71.5% between 2008 and 2016.
2. By 2016, nearly half of practices were hospital-owned. At the end of the study period, hospitals owned 47.2% of all physician practices.
3. Prices rose after mergers, but quality didn’t. Two years post-merger, prices increased by 3.3% for hospital services and 15.1% for physician services, with no measurable improvements in quality, according to the study.
4. Certain deal structures drove sharper price increases. Mergers with high potential for foreclosure (where physicians refer patients to the acquiring hospital) and recapture (where insurers must accept bundled “all-or-nothing” contracts for hospital and physician services) saw the largest price hikes.
5. Most deals escaped antitrust scrutiny. Nearly all of the mergers studied fell below the Federal Trade Commission’s Hart-Scott-Rodino reporting threshold, meaning they likely went unreviewed by federal regulators.
6. Private practices are on the decline. According to the American Medical Association’s Physician Practice Benchmark Survey, the number of physician-owned practices has dropped by nearly 20% since 2012.
7. Fewer physicians are working independently. As of 2024, only 42.4% of physicians worked in private practice, down from 60.1% in 2012, the AMA found.
8. Some specialties remain more independent. Ophthalmology has the highest rate of private practice physicians at 70.4%, followed by orthopedic surgery at 54%.
9. Hospitals are hiring faster than practices are growing. Between 2013 and 2022, the number of hospital-employed physicians increased by 33%, from around 157,000 to more than 205,000. In comparison, private practices grew by just 17%, according to a May report in the Journal of the Society of Laparoscopic and Robotic Surgeons.
10. Total employed physicians continue to rise. Over the past decade, the number of employed physicians grew by 22%, from about 620,000 in 2013 to more than 760,000 in 2022.
