Express Scripts, Inc. is an independent pharmacy benefit manager (PBM) in North America that provides a full range of pharmacy benefit management services, including retail drug card programs, home delivery pharmacy services, specialty services, drug formulary management programs and other clinical management programs for thousands of client groups that include health maintenance organizations (HMOs), health insurers, third-party administrators, employers, union-sponsored benefit plans and government health programs. During the year ended December 31, 2005, revenues from the delivery of prescription drugs represented 98.2% of its revenues. Revenues from services, such as the administration of some clients' retail pharmacy networks, sample distribution services and certain services provided by the Pharma Business Solutions (PBS) subsidiary comprised the remainder of its revenue. On October 14, 2005, the Company acquired Priority Healthcare Corporation, Inc. (Priority).