Express Scripts Holding Company (ESRX) is a Fortune 100 company that provides integrated pharmacy benefit management services, including network-pharmacy claims processing, home delivery, specialty pharmacy care, benefit design consultation, drug utilization review, formulary management, and medical and drug data analysis
From Wikipedia
Express Scripts Holding Company is a pharmacy benefit management (PBM) organization. In 2017 it was the 22nd-largest company in the United States by total revenue as well as the largest pharmacy benefit management (PBM) organization in the United States. Express Scripts had 2016 revenues of $100.752 billion. Since December 20, 2018, the company has been a direct subsidiary of Bloomfield, Connecticut-based Cigna.