Medicare Advantage (MA), a voluntary program that provides beneficiaries with an alternative way to access traditional Medicare benefits, replaced the Medicare+Choice program in 2004 and became fully operational in 2006. This issue brief reviews recent trends in the program and includes information trends in firm participation and market share, changes in beneficiary choice, and growth in MA plans available to employer groups. The brief notes that the number of Medicare beneficiaries in MA plans continues to grow, to 8.2 million at the end of 2007, up from 5.4 million in March 2005. In the first four months of 2008, enrollment increased by more than 800,000. Private fee-for-service plans account for more than half of this new growth. About one in five Medicare beneficiaries (19 percent) is enrolled in an MA plan. In addition, four main players—UnitedHealthcare, Humana, Kaiser, and Blue Cross Blue Shield—accounted for more than half of enrollment at the end of 2007.
