With 49.5 million plan enrollees, UnitedHealth Group was the largest health insurance company in the U.S. as of Dec. 31, 2017, according to Forbes.
Forbes ranked the country's largest health insurers by health plan enrollees. The top five:
1. UnitedHealth Group (Minnetonka, Minn.)
Health plan enrollees: 49.5 million
Revenue: $201 billion
2. Anthem (Indianapolis)
Health plan enrollees: 40.2 million
Revenue: $90 billion
3. Aetna (Hartford, Conn.)
Health plan enrollees: 22.2 million
Revenue: $60.6 billion
4. Cigna (Bloomfield, Conn.)
Health plan enrollees: 15.9 million
Revenue: $41.6 billion
5. Humana (Louisville, Ky.)
Health plan enrollees: 14 million
Revenue: $53.7 billion