Every fall, millions of Medicare Advantage and Part D enrollees receive a letter in the mail that’s easy to mistake for junk mail — but ignoring it can be a costly mistake. This document, called the Annual Notice of Change (ANOC), outlines exactly how your plan will change for the upcoming year. This guide explains what the ANOC is, what it contains, and why reviewing it carefully each year matters more than most beneficiaries realize.
1. What Is the ANOC?
The Annual Notice of Change is a required document that every Medicare Advantage plan and Medicare Part D plan must send to its current enrollees each year. It outlines what will change in the plan starting January 1 of the following year, including adjustments to costs, coverage, and provider networks.
By law, plans must deliver the ANOC by September 30 each year — shortly before the Medicare Open Enrollment Period begins on October 15.
2. What Information Does the ANOC Include?
The ANOC is typically a concise document (often 10–30 pages) that summarizes the most important upcoming changes. Key sections usually include:
Premium Changes
Whether your monthly premium will increase, decrease, or stay the same. Even $0-premium plans can have other costs changing elsewhere, so a flat premium doesn’t mean nothing has changed.
Deductible and Copay Changes
Updates to annual deductibles, copayments for doctor visits, and coinsurance amounts for specific services.
Prescription Drug Formulary Changes
Adjustments to which drugs are covered, their tier placement (which affects your cost), and any new utilization rules such as prior authorization or step therapy requirements.
Provider Network Changes
Whether specific doctors, specialists, or hospitals are being added or removed from the plan’s network for the coming year.
Maximum Out-of-Pocket Limit
Updates to the plan’s annual out-of-pocket spending cap, which can shift significantly year to year.
3. ANOC vs. Evidence of Coverage (EOC): What’s the Difference?
The ANOC is often confused with another document called the Evidence of Coverage (EOC). They serve different purposes:
| Document | Delivery Window | Length | Purpose |
|---|---|---|---|
| ANOC | By September 30 | Short summary (10–30 pages) | Highlights what’s changing for next year |
| EOC | September or October | Comprehensive (100+ pages) | Full details of complete plan rules and coverage |
The ANOC is meant to be a quick, digestible summary. The EOC is the full reference document you’d consult for detailed questions about specific coverage rules or appeals procedures.
4. Why the ANOC Matters More Than It Looks
It’s easy to assume a plan that worked well this year will automatically work well next year — but Medicare Advantage plans are annual contracts, and insurers are permitted to adjust benefits, costs, and networks every single year. Reasons plans change include inflation, healthcare cost trends, and shifting regulations.
Skipping a careful review of your ANOC can lead to unpleasant surprises after January 1, such as:
- A trusted specialist no longer being in-network
- A regular prescription moving to a higher cost tier
- A higher annual deductible or out-of-pocket maximum than expected
- Reduced coverage for a benefit you relied on
In some cases, a plan may also issue a separate Non-Renewal Notice, informing you that the plan itself is being discontinued for the coming year. This is sent separately from the ANOC, typically in early October, and requires you to select a new plan before the current one ends.
5. What to Do After Reading Your ANOC
Once you’ve reviewed your ANOC, here’s a simple approach to deciding your next step:
- Compare it against your actual usage — Do you see a specialist regularly? Take specific medications? Check whether those remain covered and at what cost.
- Don’t judge a plan by premium alone — A low premium can still result in higher total annual costs if your specific doctors or drugs face bigger cost-sharing changes.
- Use the Medicare Plan Finder — Starting October 1, updated plan information for the coming year becomes available at Medicare.gov, allowing full side-by-side comparisons.
- Make changes during Open Enrollment if needed — The Medicare Open Enrollment Period runs from October 15 to December 7 each year, giving you a clear window to switch plans if your current one no longer fits your needs.
Final Thoughts
The Annual Notice of Change may look like routine paperwork, but it’s one of the most important documents a Medicare Advantage or Part D enrollee receives each year. Reading it carefully — rather than setting it aside — is the best way to avoid unexpected costs or coverage gaps once the new plan year begins. Because plan details can shift meaningfully from year to year, it’s worth setting aside a few minutes every September to review your ANOC before Open Enrollment closes.
Disclaimer: This article is for general informational and educational purposes only and does not constitute medical, financial, or legal advice. Medicare plan rules, costs, and coverage details vary by plan and change annually. Always verify current details through official sources such as Medicare.gov, or consult a licensed Medicare representative or your State Health Insurance Assistance Program (SHIP) before making enrollment decisions. This site is not affiliated with or endorsed by the U.S. government or CMS.