1. UnitedHealth Group Inc.
The number one on our list of largest health insurance companies in America is th UnitedHealth Group Inc. (NYSE:UNH) with a market value $155 billion and is based out of Minnetonka, Minnesota. The company offers products and services through two operating businesses, UnitedHealthcare and Optum. Optum is a new business brand of UnitedHealth Group and operating business through Business Process Outsourcing (BPO) services. UnitedHealth serves approximately 70 million individuals throughout the United States and generated sales of over $157 billion in 2015.