In the United States, a pharmacy benefit manager (PBM) is a third-party administrator of prescription drug programs for

commercial health plans,
self-insured employer plans,
Medicare Part D plans,
Federal Employees Health Benefits Program,
and state government employee plans.

Five Biggest PBMs
The five biggest PBMs operating in the United States are very large, covering more than 50 percent of patients with pharmacy benefits.

The following are the five largest PBMs in the country, in terms of funding and growth:

ExpressScripts: ExpressScripts provides novel solutions for navigating pharmacy costs and improving patient care. Since ExpressScripts is not owned by or linked to any pharmaceutical company, their focus is entirely on its customers. Its focus on pharmacy benefits results in better patient care.

CVS Caremark: CVS Caremark is a growing PBM, providing comprehensive drug benefit services to over 2,000 healthcare plan sponsors and participants throughout the United States.

Argus: Argus is one of the last independent providers of healthcare information and services supporting Medicaid and Medicare Part D, serving some of the country's most vulnerable populations. They have a wide range of clients, from managed care organizations to pharmaceutical manufacturers.

Envision: Envision prides itself on its transparency to the public and its full disclosure on costs, agreements, and negotiations. Recently, Envision was acquired by Walgreens, so some change is expected moving forward.

ProCare RX: ProCare RX ( private company ) is national pharmacy benefit manager with decades of experience in healthcare information technology.

EVHC

ESRX

Five Biggest PBMs
The five biggest PBMs operating in the United States are very large, covering more than 50 percent of patients with pharmacy benefits. The following are the five largest PBMs in the country, in terms of funding and growth:

ExpressScripts: ExpressScripts provides novel solutions for navigating pharmacy costs and improving patient care. Since ExpressScripts is not owned by or linked to any pharmaceutical company, their focus is entirely on its customers. Its focus on pharmacy benefits results in better patient care.

CVS Caremark: CVS Caremark is a growing PBM, providing comprehensive drug benefit services to over 2,000 healthcare plan sponsors and participants throughout the United States.

Argus: Argus is one of the last independent providers of healthcare information and services supporting Medicaid and Medicare Part D, serving some of the country's most vulnerable populations. They have a wide range of clients, from managed care organizations to pharmaceutical manufacturers.

Envision: Envision prides itself on its transparency to the public and its full disclosure on costs, agreements, and negotiations. Recently, Envision was acquired by Walgreens, so some change is expected moving forward.

ProCare RX: ProCare RX ( private company )is national pharmacy benefit manager with decades of experience in healthcare information technology.