Sometime in September, a letter from your Medicare Advantage or Part D plan is going to show up in your mailbox. It looks routine. It is not. That letter, called the Annual Notice of Change (ANOC), is the single most useful document you will get all year if you want to know whether your plan is still a good fit for 2027.
Most people glance at it, see a wall of text, and set it aside. That is understandable, but it is also how people end up paying more than they need to or losing a benefit they relied on. This guide breaks down exactly what the ANOC letter says, what it leaves out, and how to use it to prepare before Annual Enrollment opens October 15.
What Is the ANOC Letter?
Every Medicare Advantage and Part D plan is required to send its members a letter each year describing how the plan is changing for the next plan year. It covers premiums, deductibles, copays, drug coverage, extra benefits, and whether the plan is continuing at all. Plans must deliver it by September 30, about two weeks before the Annual Enrollment Period begins.
Think of it as your plan's report card for the coming year, written by the plan itself. It is not marketing. It is a required disclosure, which means the information is accurate, but it is also written to be technically complete rather than easy to skim.
The Five Things to Check First
You do not need to read every page. Focus on these five sections, in this order.
Your ANOC review checklist:
- Premium and out-of-pocket maximum: even a small increase adds up over a year
- Plan continuation: check whether your plan is exiting the market or changing its name
- Prescription drug tiers: look up each of your medications by name
- Extra benefits: dental, vision, hearing, transportation, and fitness allowances
- Provider network language: note if it mentions broad changes, then verify separately
Premiums and out-of-pocket costs. A jump from a $0 premium to even $15 a month is $180 a year. For 2026, Part D also carries a $2,100 annual cap on out-of-pocket prescription costs, so check whether your plan's structure around that cap changed.
Whether your plan is still around. The first section of most ANOC letters states plainly if the plan is discontinuing or changing its name. If it is exiting, the letter will also say whether you are being automatically moved into a different plan, which is worth double-checking rather than assuming it is the best option for you.
Drug tier changes. This is the section that catches people off guard most often. A medication that cost $10 this year can move to a higher tier and cost $60 next year, or it can be dropped from the formulary entirely. Go through your actual prescription list and check each one by name.
Extra benefits. Dental, vision, hearing, over-the-counter allowances, meal delivery, and gym memberships are usually the first things trimmed when a plan needs to cut costs. If you use any of these regularly, this section deserves a close read. Our guide to Medicare Advantage plans in California covers how these extra benefits typically work.
What the ANOC Letter Will Not Tell You
Here is the part that surprises people: the ANOC letter will usually say something general like "our provider network has changed," but it will not list which specific doctors, clinics, or hospitals were added or dropped. You have to check that yourself.
Do this separately: Call your doctor's office directly and ask which plans they will accept next year, or search the plan's online provider directory using your doctor's name. Do not assume network status carried over from last year, especially in larger California counties where networks shift often.
Star Ratings: The Other Number Worth Checking
Alongside your ANOC letter, it is worth pulling up your plan's Medicare Star Rating. CMS scores every Medicare Advantage and Part D plan from 1 to 5 stars across roughly 40 quality measures, including preventive care access, chronic condition management, member experience, and how the plan handles complaints. For 2026, the average plan rating sits just under 4 stars, and roughly two-thirds of Medicare Advantage enrollees are in a plan rated 4 stars or higher.
If a 5-star plan becomes available in your county, California seniors get a bonus option most people do not know about: a 5-Star Special Enrollment Period that runs from December 8 through November 30 of the following year, letting you switch into that plan once outside of the normal AEP window.
Turning This Into a Real Comparison
Once you know what changed in your current plan, you are ready to compare it against alternatives, not just renew it out of habit. Start with the Medicare in California guide for the full landscape, then look at whether Medicare Advantage or a Medicare Supplement plan fits your situation better this year. If your drug costs changed significantly, our Part D coverage guide walks through how formularies and tiers work in more detail.
Prefer to review this in Spanish, or helping a family member who does? Our sister site Beneficios Medicare covers the same plan comparison topics for Spanish-speaking readers.
Not sure what your ANOC letter means for you?
A licensed Medicare specialist can read it with you, check your specific drugs and doctors, and flag anything worth switching over. No cost, no pressure.
Schedule a Free Plan ReviewFrequently Asked Questions
What is a Medicare ANOC letter?
ANOC stands for Annual Notice of Change. It is a required letter from your Medicare Advantage or Part D plan explaining how your premium, benefits, drug coverage, and network are changing for the next plan year.
When does the ANOC letter arrive?
Plans must deliver it by September 30 each year, about two weeks before Annual Enrollment opens October 15.
What should I check first in my ANOC letter?
Start with your premium and out-of-pocket maximum, then check whether your plan is exiting the market, review drug tier changes for your medications, and confirm your extra benefits are unchanged.
Does the ANOC letter tell me if my doctor is still in network?
No. It notes general network changes but will not list specific doctors added or dropped. Check the plan's provider directory or call your doctor's office directly.
What is a Medicare Star Rating and why does it matter?
CMS rates plans 1 to 5 stars based on around 40 quality measures. For 2026, the average rating is just under 4 stars. A 5-star plan in your area can be joined through a special enrollment period running December 8 through November 30.
One More Thought
The ANOC letter is easy to ignore because it arrives looking like routine paperwork. But it is the one document every year written specifically to tell you what changed about your own coverage. Reading it carefully, even just the five sections above, takes about fifteen minutes and can be the difference between a smooth renewal and an unpleasant surprise in January.