Question: who is the largest pbm?
Answer: Caremark (CVS Health) / Aetna: 30 percent. Express Scripts: 23 percent. OptumRx (UnitedHealth): 23 percent. Humana Pharmacy Solutions: 7 percent. MedImpact Healthcare Systems: 6 percent. Prime Therapeutics: 6 percent. All other PBMs + cash pay: 4 percent.