Medicare Annual Notice of Change (ANOC): What It Is & Why It Matters

If you're on a Medicare Advantage or Part D plan, a letter arrives every September that's easy to set aside unread. It shouldn't be — the Annual Notice of Change (ANOC) is one of the most useful documents your plan sends you all year.

What the ANOC actually is

The ANOC is a required annual mailing that spells out exactly what's changing about your plan for the upcoming calendar year — before those changes take effect on January 1. Every Medicare Advantage and Part D plan is required to send one to its members by the end of September.

What it covers

• Premium changes — whether your monthly cost is going up, down, or staying the same
• Deductible and copay changes — for both medical services and prescription drugs
• Provider network changes — sometimes doctors, hospitals, or specialists are added or dropped
• Drug formulary changes — medications can move to different cost tiers, get added, or get dropped entirely
• Benefit changes — extra benefits like dental, vision, hearing, or fitness programs can expand, shrink, or disappear

Why September timing matters

The ANOC arrives right before the Annual Enrollment Period (October 15 – December 7). That timing isn't a coincidence — it's designed to give you a few weeks to review the upcoming changes before you have to decide whether to keep your plan, switch to a different one, or make no change at all.

What to actually do with it

1. Check whether your premium, deductible, or copays are changing — and by how much
2. Compare the new drug formulary against your current medications, especially anything expensive or specialized
3. Confirm your regular doctors and specialists are still listed as in-network for next year
4. Note any extra benefits (dental, vision, hearing, OTC allowance) that are changing
5. Decide whether anything on the list is significant enough to prompt a closer look at other options

If you don't do anything with it

If you don't take action during AEP, your current plan generally continues automatically into the new year — changes and all. That's not necessarily a problem, but it does mean the changes in your ANOC become your reality by default, whether or not you noticed them.