In the United States, a pharmacy benefit manager is a third-party administrator of prescription drug programs for commercial health plans, self-insured employer plans, Medicare Part D plans, the Federal Employees Health Benefits Program, and state. Pharmacy Benefit Managers (PBMs) administer prescription drug plans for more than 266 million Americans who have health insurance from a variety of. In the United States, a pharmacy benefit manager (PBM) is a third-party administrator of prescription drug programs for commercial health plans, self- insured. Pharmacy benefit managers, or PBMs, are companies that manage prescription drug benefits on behalf of health insurers, Medicare Part D. Very large pharmacy benefits management (PBM) companies cover prescription drugs for more than 50 percent of Americans with health insurance. What Is the Pharmacy Benefit Management (PBM) Industry?.