Medicare Advantage Annual Notice of Change

What the ANOC Is and When It Arrives

Every September, Medicare Advantage plans mail their Annual Notice of Change (ANOC) to all current enrollees. The document details every benefit, cost, and network modification that will take effect January 1 of the following year. It arrives just before the Annual Enrollment Period opens on October 15, giving families roughly six weeks to review changes and decide whether to stay, switch plans, or leave Medicare Advantage entirely.

The ANOC is the plan's legal obligation to disclose changes. If you don't receive one by September 30, call the plan directly—missing the notice doesn't extend your decision window.

What to Check First

Premium changes. Even plans advertised as "$0 premium" can add premiums year to year. Check whether the monthly cost increased and by how much. A $30/month premium increase is $360 annually—meaningful for fixed-income retirees.

Out-of-pocket maximum changes. The maximum your parent can spend in-network before the plan pays 100% may rise or fall. In 2026, the federal ceiling is $9,250, but plans can set lower caps. If your parent's plan raised its cap from $4,500 to $6,500, their financial exposure during a serious health event just increased by $2,000.

Provider network changes. This is the one most families miss. The ANOC may list hospitals, specialist groups, or primary care practices that are leaving the network. A dropped hospital system or specialty group can upend continuity of care for a parent managing chronic conditions. Cross-reference the ANOC's network changes against every provider your parent currently sees.

Formulary changes. The plan's drug formulary—the list of covered medications and their tier placement—changes annually. A drug that was Tier 2 (low copay) last year might move to Tier 3 or 4 (higher copay) or get removed from the formulary entirely. Check every medication your parent takes against the new formulary. A single tier change on an expensive medication can add hundreds of dollars annually.

Prior authorization changes. Plans can expand the list of services requiring prior authorization. If your parent's plan added prior authorization for a service they use regularly—specialist referrals, imaging, certain procedures—that's a material change in how easily they can access care.

When to Switch

Not every ANOC change warrants action. Minor premium adjustments or formulary shifts may not affect your parent's situation. But certain changes should trigger a serious evaluation:

• A key specialist or hospital drops out of network
• The out-of-pocket maximum increases significantly
• A regularly used medication moves to a higher tier or off the formulary
• Prior authorization requirements expand to cover services your parent uses frequently
• The plan's star rating dropped significantly (check Medicare Plan Finder)

During the Annual Enrollment Period (October 15–December 7), your parent can switch to another Medicare Advantage plan, drop to Original Medicare with a standalone Part D plan, or—if guaranteed-issue rights apply—add Medigap to Original Medicare.

The Structural Risk the ANOC Reveals

The ANOC is an annual reminder that Medicare Advantage benefits are not permanent. The plan your parent chose three years ago may look entirely different today—different network, different formulary, different cost-sharing, different prior authorization requirements. Each year's ANOC is the plan reasserting that it can change the terms of the deal.

Under Original Medicare with Medigap, this dynamic doesn't exist. Medigap Plan G covers the same gaps every year—Part A deductible, Part B coinsurance, SNF coinsurance—and the coverage letter never changes. The only variable is the premium, and that's driven by the insurer's pricing model and healthcare inflation, not by annual benefit redesigns.

Our Medigap vs Medicare Advantage guide helps your family evaluate whether this year's ANOC changes tip the balance toward switching coverage paths, with a cost comparison framework and provider verification worksheet.

See more United States guides →