UnitedHealth Group now employs or is affiliated with 10% of all physicians in the U.S.

UnitedHealth Group has about 90,000 employed or affiliated doctors, approximately 10% of all physicians in the U.S.

The number — disclosed Wednesday at the company’s investor day by Amar Desai, the CEO of UnitedHealth’s Optum Health division — means the company acquired or hired 20,000 doctors in the past year alone.

The rapid growth of UnitedHealth’s physician base underscores how the company, which already is the country’s largest private health insurer, is looking to control more of the health care delivery system, and how this growth is going unchecked by antitrust agencies.