Express Scripts

Founded in 1989, MedAssist is one of the national leaders in health care revenue cycle management. It is a privately held corporation that serves more than 1,000 health care providers through over 1,400 employees. The company offers several patient services that include call center operations, including patient contact and registration, insurance verification and certification, financial counseling, eligibility prescreening, patient notification of expected liability and emergency department verification services. It also provides a variety of eligibility services, including Medicaid management and review, self-pay conversion, and identification and processing of internal charity services. MedAssist is located in Louisville, Ky.

Humana is one of the nation's largest publicly traded health benefits companies, with approximately 7 million medical members. Humana offers coordinated health insurance coverage and related services including traditional and Internet-based plans, employer groups, government-sponsored plans and individuals through administrative service products, preferred provider organizations, consumer driven plans and government-sponsored plans. The company's specialty products are comprised of dental, life and disability insurance, which complement its core health offerings. Humana provides health benefits and related services to companies ranging from fewer than 10 to tens of thousands of employees. Michael B. McCallister has been the chief executive officer of Humana for more than six years. He has been with the health care provider for over 32 years. McCallister earned a BS degree from Louisiana Tech University, and a MBA from Pepperdine University. Humana has offices in 15 states including Arizona, Illinois, Georgia, Texas, Missouri and a branch in Puerto Rico. The company is located in Louisville, Ky.