A Brookings Institution analysis published Sept. 3 mapping vertical integration among the five largest U.S. health insurers found UnitedHealth Group’s Optum Health division generated $100.5 billion in 2025 revenue, 63% of it paid by UnitedHealth’s own health plans.
That structure runs through physician practices, senior-focused primary care clinics and home health agencies that increasingly compete with independent groups for patients and referrals.
Five things independent physician and primary care organizations should track, according to the report:
1. Optum controlled 2.71% of the national primary care market by visit volume in 2023, but that share runs far higher in specific counties: 44.9% in Snohomish County, Wash., and 40.1% in Contra Costa County, Calif.
2. Humana’s CenterWell Senior Primary Care generated $6 billion in 2025 revenue, and 63% of that, $3.8 billion, came from Humana’s own insurance plans rather than outside payers, per Brookings. CenterWell and sister brand Conviva now operate more than 340 senior-focused clinics, with 20 to 30 more opening in 2025, including 11 inside former Walmart Health locations.
3. Optum paid $5.4 billion for home health operator LHC Group in 2023 and closed a $3.3 billion acquisition of Amedisys in August 2025 after a two-year Justice Department challenge that forced divestiture of 164 home health and hospice locations worth about $528 million in annual revenue.
4. Optum’s ASC arm, SCA Health, now operates more than 320 ASCs with a network of 9,200 physicians, part of the infrastructure that helped Optum Health post $63.6 billion of its $100.5 billion in 2025 revenue as payments from UnitedHealth’s own health plans, per Brookings.
5. Brookings researchers warned that internal financial flows like these create “abundant opportunities to game regulations, hide profits through tunneling, and foreclose markets to rivals.”
At the Becker’s 32nd Annual Meeting: The Business and Operations of ASCs, taking place October 29-31 in Chicago, ASC leaders, surgeons and healthcare executives will explore strategies to drive growth, enhance operational performance, navigate reimbursement challenges and prepare for the future of ambulatory surgery. Apply for complimentary registration now.
