Aetna is a health care benefits company. The company conducts its operations in three business segments: Health Care, which provides medical, pharmacy benefit management services, dental, behavioral health and vision plans provided on both an insured basis and an employer-funded basis and businesses products and services that complement its medical products; Group Insurance, which primarily includes group life insurance and group disability products and long-term care products; and Large Case Pensions, which manages a variety of retirement products (including pension and annuity products) primarily for tax-qualified pension plans.

Centene is an insurance holding company. The company's Managed Care segment provides health plan coverage to individuals through government subsidized programs. The company also provides a variety of individual, small group, and large group commercial healthcare products, both to employers and directly to members in the Managed Care segment. The company's Specialty Services segment consists of the company's specialty companies prviding healthcare services and products to state programs, correctional facilities, healthcare organizations, employer groups and other commercial organizations, as well as to its own subsidiaries. The Specialty Service segment also includes the Government Contracts business.

Cigna is a holding company. The company is a global health services organization. Through its subsidiaries, the company provides a set of medical, dental, disability, life and accident insurance and related products and services. The majority of which are provides through employers and other groups such as governmental and non-governmental organizations, unions and associations. The company also provides commercial health and dental insurance, Medicare and Medicaid products and health, life and accident insurance coverages to individuals in the U.S. and selected international markets. The company's segments include: Global Health Care; Global Supplemental Benefits; Group Disability and Life; and Other Operations.

Humana is a holding company. Through its subsidiaries, the company is a health and well-being company. The company manages its business with three segments: Retail, which consists of products sold on a retail basis to individuals including medical and supplemental benefit plans, such as Medicare and state-based Medicaid Contracts; Group and Specialty, which consists of employer group commercial fully-insured medical and specialty health insurance benefits, including dental, vision and life insurance benefits, as well as administrative services only; and Healthcare Services, which includes pharmacy solutions, provider services, clinical care services, and predictive modeling and informatics services

UnitedHealth Group is a health care company. The company has four reportable segments across its two business platforms, UnitedHealthcare and Optum: UnitedHealthcare, which provides health care benefits to an array of customers and markets through its UnitedHealthcare Employer & Individual, UnitedHealthcare Medicare & Retirement, UnitedHealthcare Community & State and UnitedHealthcare Global; OptumHealth, which serves the physical, emotional and health-related financial needs of individuals; OptumInsight, which provides services, technology and health care knowledge to main participants in the health care industry; and OptumRx, which provides pharmacy care services and programs.