Groups advocating for increased transparency in the world of pharmacy benefits managers often cite "spread pricing" as one way PBMs drive up the cost of prescription drugs for employers and consumers. While the practice is often hard to expose, the upcoming issue of Fortune Magazine includes an in-depth piece, called "Painful prescription," which does just that.

Reporter Katherine Eban uses the story of Meridian Health Systems — a former customer of the nation's largest PBM, Express Scripts — to show the sometimes drastic difference in what PBMs charge patients to fill prescriptions and what they in turn pay pharmacies to dispense those prescriptions. This difference often leads to greater profits for the PBM and increased costs for the employer.       

Robert Schenk, who oversees Meridian's spending on employee medications, dug through the employer's bills to discover just how rampant the practice was. One such example he found were charges for generic amoxicillin — Meridian was billed $92.53 when an employee filled the prescription, but Express Scripts paid only $26.91 to the pharmacy to fill the same prescription.