Who owns your doctor? A decade of trends in physician practice ownership in dermatology and gastroenterology.

Introduction: How physicians deliver care is shaped by who owns their practice, yet no study comprehensively maps the ownership landscape within a specialty. Methods: Using Medicare claims and hand-collected transaction data from 2012 to 2022, we classified dermatologists and gastroenterologists into 5 mutually exclusive ownership categories-independent, corporate chain, hospital or health system, insurer, and supergroup-and distinguished 2 pathways out of independent practice: acquisition and organic physician entry. Results: Independent practice declined from 62% to 44% of dermatologists and from 52% to 31% of gastroenterologists. By 2022, corporate chains, nearly all private-equity backed, accounted for 16% of dermatologists and 11% of gastroenterologists, while hospital ownership reached 26% and 47%. Hospitals were the largest nonindependent owners in both specialties; corporate chains grew fastest in dermatology. Corporate chains pursued different growth strategies by specialty: Acquisitions of established physician-owned supergroups dominated gastroenterology, while growth in dermatology also came from building new chains from small practices. Increasingly, corporate growth was driven by organic entry of both experienced physicians and recent graduates, overtaking acquisitions by 2021 in dermatology. Conclusion: Who owns a doctor's practice, and how that ownership grows, varies widely-heterogeneity that has implications for patient care and policy addressing provider consolidation.