With about 50 million covered lives and 1.2 billion annually processed prescription claims, UnitedHealth is one of the largest MCOs and PBMs in the United States. The firm provides health insurance services to its members through products for every major insurance market--individual, group, and government sponsored. The firm also provides back-office services to providers through its Optum segment. UnitedHealth has a large nationwide operation and competes in most major U.S. geographies.