UnitedHealthcare is the country's largest health insurance company, covering 48.9 million members, according to ValuePenguin, a resource for consumers looking to make more informed financial decisions.
The five largest health insurers, ranked by membership:
1. UnitedHealthcare Group: 48.9 million
2. Anthem: 40.8 million
3. Aetna: 22.1 million
4. Cigna: 17 million
5. Humana: 16.6 million