Medicare Advantage Plan
A Medicare Advantage Plan (Medicare Part C) is an alternative way to receive Medicare benefits through a private insurer that contracts with the federal government — bundling Parts A, B, and usually D coverage into a single managed-care plan, often with lower premiums than Original Medicare plus Medigap but with network restrictions and out-of-pocket caps.
Medicare Advantage represents the managed-care alternative to the traditional fee-for-service structure of Original Medicare. Beneficiaries enrolled in Medicare Advantage remain in Medicare — the federal government continues to pay the insurer a risk-adjusted per-member monthly premium on their behalf — but they receive services through the Advantage plan's provider network and are subject to its rules, authorizations, and cost-sharing structure rather than those of Original Medicare.
The most common Medicare Advantage plan types are Health Maintenance Organizations (HMOs), which require use of network providers and often require referrals to specialists, and Preferred Provider Organizations (PPOs), which allow out-of-network use at higher cost. Special Needs Plans (SNPs) are a Medicare Advantage variant targeted to specific populations — dual-eligible individuals (covered by both Medicare and Medicaid), institutionalized beneficiaries, or those with specific chronic conditions.
Medicare Advantage plans must cover all Original Medicare benefits and may include additional benefits not covered by Original Medicare, such as routine dental, vision, hearing aids, and fitness memberships. Many Advantage plans charge $0 additional premium beyond the standard Part B premium, and some plans offer part B premium reduction credits — features that have driven explosive enrollment growth, with Advantage now covering more than half of all Medicare beneficiaries.
The fundamental tradeoff versus Original Medicare plus Medigap is flexibility versus cost. An Original Medicare beneficiary with a Plan G Medigap policy can see any physician or specialist in the United States who accepts Medicare — roughly 92% of physicians — without network restrictions, referrals, or prior authorizations. A Medicare Advantage HMO enrollee may face significant administrative barriers: prior authorizations for procedures, network limitations that restrict access to specific hospitals or specialists, and the possibility that a beloved physician is not in-network.
Beneficiaries who develop serious illness while enrolled in Medicare Advantage sometimes find the prior authorization requirements and network limitations burdensome and wish to return to Original Medicare — but returning to Original Medicare plus a Medigap policy requires medical underwriting in most states (outside the limited Medigap trial right period and a few state-specific protections). This makes the Advantage-to-Medigap transition difficult for those who develop significant health conditions.