As of my knowledge cutoff of 2021, the largest health insurance companies in the United States based on their total revenue are:
- UnitedHealth Group
- Aetna (a subsidiary of CVS Health)
These companies dominate the health insurance market in the United States and collectively cover a significant portion of the population. However, it’s important to note that there are many other health insurance providers in the market, including regional and local companies, as well as government-sponsored programs like Medicare and Medicaid.