Express Scripts Holding Company is a pharmacy benefit management (PBM) company. The Company is engaged in providing healthcare management and administration services to its clients, including managed care organizations, health insurers, third-party administrators, employers, union-sponsored benefit plans, workers' compensation plans and government health programs. The Company operates through two segments: PBM and Other Business Operations. The PBM segment includes its integrated PBM operations and specialty pharmacy operations. Its Other Business Operations segment includes its subsidiary, United BioSource Corporation (UBC), and its specialty distribution operations. Its integrated PBM services include clinical solutions, Express Scripts SafeGuardRx, specialized pharmacy care, home delivery pharmacy services, specialty pharmacy services, retail network pharmacy administration, benefit design consultation, drug utilization review and drug formulary management.