UnitedHealth Group Incorporated is an American multinational company based in Eden Prairie, Minnesota, specializing in health insurance and health care services. Selling insurance products under UnitedHealthcare, and health care services under the Optum brand, it is the world's ninth-largest company by revenue and the largest health care company by revenue. The company is ranked fourth on the 2026 Fortune Global 500. UnitedHealth Group had a market capitalization of more than $300 billion as of year-end 2025. The company is the largest health insurer in the United States, insuring over 50 million people, and operates globally. UnitedHealth Group has faced numerous investigations, lawsuits, and fines, including SEC enforcement for stock option backdating, Medicare over-billing, unfair claims practices, mental health treatment denials, and anticompetitive behavior.