An annual notice of change (ANOC) is a letter sent every fall by Medicare Advantage or Medicare Part D plans. This letter outlines any changes in coverage or costs for the following calendar year.

The ANOC can help you decide whether you need to change your coverage during the open enrollment period between October 15 and December 7.

Read on to learn about when to expect an ANOC from your Medicare plan, what it means, and what to do when you get it.

Because private insurers run Medicare Advantage and Part D plans, they’ll typically send you an ANOC for their plans around September of every year.

Some examples of changes you might be notified of in this letter include changes to costs, coverage, your service area, or your drug formulary.

Does Original Medicare or Medigap send an ANOC?

Original Medicare (parts A and B) doesn’t generally send an ANOC because it’s a standardized plan. Coverage doesn’t change annually. While costs do change, they’re the same nationwide and listed on Medicare.gov.

Plus, although Medigap plans are privately managed, these are also standardized and don’t have annual coverage changes. That said, your Medigap premiums could still change annually, so it’s important to check before deciding whether to re-enroll.

When you receive your ANOC, read it thoroughly and look for any cost changes to deductibles, copays, and premiums. Unlike Original Medicare, which sets standard costs nationally, costs for private plans can vary from year to year.

Next, look for any changes to your plan’s coverage. This means looking at additions or exclusions of certain services from coverage from the previous year.

With Part D plans, look for changes to the tier classification of your prescription medication, which may raise your out-of-pocket drug costs. Sometimes, a drug that was previously covered is no longer covered at all.

In addition, your plan could change which doctors or hospitals it includes in its networks or which pharmacies it works with. This means your preferred provider may now be out of network.

If you don’t receive an ANOC by the time open enrollment begins, reach out to your plan. Without an ANOC, it’s hard to determine whether your current plan still suits your needs for the upcoming year.

When you do get it, and after reviewing the document and any changes, you can determine whether you need to make any changes.

Another thing that might show up in ANOC is a notification that your plan no longer works with Medicare. In this case, your coverage may not automatically renew.

In this case, your ANOC should outline what happened and the steps you must take to enroll in a new plan. If you don’t select another Medicare Advantage plan, you’ll be automatically enrolled in Original Medicare when your current coverage ends.

Every fall, you’ll receive the ANOC letter from your Medicare Advantage or Part D plan. It will outline any changes to your coverage or costs for the upcoming year.

It’s important to review this letter and see if you need to make any adjustments during the open enrollment period.