The PBM provides services like negotiating prices with drug manufacturers and pharmacies, processing prescription claims and/or creating drug formularies (lists of approved medicines).

Health insurers and others count on the PBM's pharmaceutical expertise to keep drug prices low. Controlling pharmaceutical expenses affects the rate consumers pay for health coverage as well as their out-of-pocket costs.

While several companies provide PBM services, the one affecting your prescription coverage is a decision between the health insurance company, self-insured employer, union or government entity. Covered individuals cannot choose which PBM provides prescription services.