Every September, millions of Medicare Advantage and Part D beneficiaries receive an envelope — or an email — that many skim and set aside without reading. That document, the Annual Notice of Change (ANOC), is actually one of the most useful tools you have before the Annual Enrollment Period: it tells you exactly what is changing in your plan for the coming year, before the change catches you off guard in January. This guide explains what the ANOC is, when it arrives, what to look for inside it, and what to do if the changes do not work for you.
What the ANOC is, and why your plan must send it
The Annual Notice of Change is a document Medicare requires every insurer to send to each member of a Medicare Advantage plan or standalone Part D plan, summarizing how your coverage will change from the current year to the next. The rule exists precisely because plans can — and frequently do — change premiums, deductibles, copays, the provider network, and the drug formulary from one year to the next, and Medicare wants you to have that information with enough time to act.
Unlike a marketing letter, the ANOC follows a format standardized by Medicare, so even if you switch insurers from year to year, the document will have a similar, comparable structure. That makes it easier to review calmly instead of having to decode a different format every time.
When it arrives: the late-September window
Medicare requires plans to send the ANOC no later than September 30 each year, so most beneficiaries receive it during the last two weeks of September, either by printed mail or electronically if you consented to digital communication. That timing is no accident — it gives you roughly two weeks of lead time before the Annual Enrollment Period begins on October 15.
If you have not received your ANOC by early October, do not assume your plan made no changes: call your insurer directly or check your online account, because sometimes mail is delayed or the document was sent to an outdated address or email.
Availability, cost, benefits, and eligibility vary by person, product, contract, and insurance company, as well as by your service area. Guarantees are subject to the claims-paying ability of the issuing insurance company. Karla Arámburo is not affiliated with or endorsed by Medicare or the federal government.
What to look for inside the ANOC
The document is usually organized into clear sections, but five areas deserve your special attention:
| What to check | Why it matters |
|---|---|
| Monthly premium | An increase, even a small one, adds up over the plan's twelve months |
| Deductibles and copays | A higher specialist or ER copay matters more if you see doctors often |
| Provider network | A hospital or medical group can leave the network from one year to the next without individual notice |
| Drug formulary | Your medication can move to a higher cost tier or require new prior authorization |
| Supplemental benefits | Dental, vision, transportation, or wellness-card benefits can shrink or disappear |
Formulary and network: the two changes that catch people most off guard
Of the five points above, changes to the drug formulary and the provider network are the ones that most often catch people off guard, precisely because they are not always obvious at a glance. A medication you used without issue all year can move to a higher cost-sharing tier, or start requiring prior authorization or step therapy, without the medication's name or your dosage changing at all.
Similarly, an entire hospital or medical group can leave your plan's network from one year to the next without an individual notice addressed specifically to you — the only formal notification is, precisely, the ANOC and the updated provider directory. That is why it is worth reviewing both documents together, rather than assuming that because your doctor was covered this year, they will remain covered next year.
What to do if the changes don't work for you
If the ANOC shows your premium going up, your medication leaving the formulary, or your preferred hospital leaving the network, you do not have to simply accept those changes. The Annual Enrollment Period, October 15 through December 7, exists exactly for this: comparing your current plan against the other options available in your ZIP code and switching if another plan fits your situation better for the coming year. See our 2026 Medicare enrollment dates guide for the full calendar of the year.
If you are considering leaving Medicare Advantage for Original Medicare with a Medigap supplement, keep in mind that outside your guaranteed-issue eligibility period you usually go through medical underwriting. Our general Medigap guide explains how that process works, and a premium increase caused by IRMAA, if it applies to you, is explained in our 2026 IRMAA guide.
Reviewing your ANOC with free bilingual help
I am Karla Arámburo, an independent, bilingual insurance agent licensed to serve families in Orange, Los Angeles, San Diego, and Riverside counties in Southern California, including residents of cities like Riverside and Long Beach. You can bring me your ANOC as soon as it arrives and we can review it together line by line, in Spanish or English, so you understand exactly what is changing and whether it makes sense to compare other options before December 7.
You can call or text (619) 321-8733 to schedule a free consultation. As an independent agent, I compare the specific insurers and plans available for your ZIP code, not just one plan, and I also offer life insurance options that accept an ITIN. This page is general education, not individualized advice or an enrollment recommendation.
Frequently asked questions
What exactly is the Annual Notice of Change (ANOC)?
It is a document your Medicare Advantage or Part D plan is legally required to send you every year, detailing how your premiums, deductibles, copays, provider network, and drug formulary will change starting the following January 1. It is not marketing or an optional notice — it is a federal requirement so you can decide with real information whether to stay in the same plan.
When should my ANOC arrive this year?
Insurers must send it no later than September 30, so most beneficiaries receive it during the last two weeks of that month, either by mail or electronically if you opted into digital communication. If you have not received it by early October, it is worth calling your insurer directly.
Is the ANOC the same as the Evidence of Coverage (EOC)?
No. The ANOC is a brief summary, usually just a few pages, focused only on what is changing. The Evidence of Coverage is the full document with every detail of the plan for the upcoming year, and it is usually sent alongside the ANOC or made available shortly after on your insurer's website.
If my plan's price goes up, do I have to switch automatically?
No. If you do nothing during the Annual Enrollment Period, you remain in your current plan with the changes described in the ANOC starting in January. Switching is an option, not a requirement, but it is worth comparing before deciding to stay out of inertia.
What happens if my medication is no longer on next year's formulary?
The ANOC must indicate if a medication you currently take will leave the formulary, move to a different cost tier, or require new prior authorization. If that happens, you can ask your doctor about a formulary exception, switch to a covered alternative, or compare other Part D or Medicare Advantage plans during the AEP.
How do I know if my doctor will still be in-network next year?
The ANOC generally does not list individual doctors; it only notes general changes to the network structure. To confirm whether a specific doctor or specialist will still be covered, check your insurer's updated provider directory for the upcoming year or call both the doctor's office and the insurer directly before deciding.
Can I switch plans as soon as I receive my ANOC?
You can start comparing right away, but formal enrollment for a change that takes effect January 1 is only processed during the Annual Enrollment Period, October 15 through December 7. Reviewing your ANOC as soon as it arrives gives you plenty of time to compare calmly before that deadline.
Should I throw away the ANOC if I decide to stay in my current plan?
I do not recommend it. Keep it at least through the end of the upcoming coverage year, because it details the cost and benefit changes that will apply, and it can be useful as a reference if a dispute comes up over a copay or authorization during the year.