Humana is one of the largest private health insurers in the U.S. with a focus on administering Medicare Advantage plans. The firm has built a niche specializing in government-sponsored programs, with nearly all its medical membership stemming from individual and group Medicare Advantage, Medicaid, and the military's Tricare program. The firm is also a leader in stand-alone prescription drug plans for seniors enrolled in traditional fee-for-service Medicare. Beyond medical insurance, the company provides other healthcare services, including primary-care services, at-home services, and pharmacy benefit management.