Size matters for health insurance companies and pharmacy benefits managers for at least two reasons. First, growing large allows insurers and PBMs to maximize profits by creating economies of scale, as discussed here in the context of how prescription drug insurance coverage works.
Second, and why members of the pharmacy profession should know which PBMs dominate the market, very large companies have the greatest leverage to negotiate reimbursement rates for medications and patient care services.
The five biggest PBMs operating in the United States are very large, covering more than 50% of patients with pharmacy benefits. These rankings and numbers come from a survey of PBM performance during the second quarter of 2011 conducted by Atlantic Information Services (link requires free registration).
Express Scripts, Inc.
- Website: http://www.express-scripts.com/corporate
- Covered Lives: No. 1, with 90 million
- Dispensed Prescriptions Paid: No. 2, with 640.1 million claims
Express Script bought Medco (see below) in early 2012. Organizations representing pharmacists and a group of patients have filed a federal lawsuit to dissolve the merger, claiming the mega-PBM unfairly restricts choice and access in the insurance market.
CVS Caremark
- Website: http://info.cvscaremark.com
- Covered Lives: No. 2, with 85.1 million
- Dispensed Prescriptions Paid: No. 3, with 584.8 million claims
When CVS/pharmacy acquired Caremark in 2007, the chain drugstore took over management of the pharmacy benefits for everyone already covered by the PBM. More than 65,000 pharmacies participate in this provider's network.
Health Information Designs, Inc.
- Website: http://www.hidinc.com
- Covered Lives: No. 3, with 69.5 million
- Dispensed Prescriptions Paid: Not in the top 10 for claims
Health Information Designs primarily supports Medicaid managed care programs and other PBMs by helping to develop and implement formularies, prescription drug monitoring programs and drug utilization review protocols.
Medco Health Solutions, Inc.
- Website: https://host1.medcohealth.com/consumer/site/home
- Covered Lives: No. 4, with 65 million
- Dispensed Prescriptions Paid: No. 1, with 740.1 million claims
As of mid-August 2012, Medco drug cards, claim processing systems and web services remained functional.
ICORE Healthcare
- Website: http://www.icorehealthcare.com
- Covered Lives: No. 5, with 60 million
- Dispensed Prescriptions Paid: Not in the top 10 for claims
ICORE focuses on handling claims for specialty pharmaceuticals, such as those used to treat infertility, multiple sclerosis, HIV/AIDs and hepatitis C.
It's Complicated
One "covered life" does not equal one policy holder. For instance, a parent who has prescription drug coverage through a health insurance policy provider through his or employer is the policy holder. A spouse, child or dependent parent named on the employee's policy counts as an additional covered life.
Also, sharp-eyed readers will note that the covered lives and prescription volume ranking for three of the PBMs do not all match. This listing prioritizes numbers of enrollees because pharmacists and pharmacy technicians are most likely to encounter patients with pharmacy benefits provided by the listed companies. In the interest of completeness and to satisfy the curious, the two top-five PBMs by prescription volume not already identified are
- No. 4, Argus Health Systems, Inc. (also eighth by covered lives)
- No. 5, OptumRx (formerly Prescription Solutions)

