Medicare AEP vs OEP

AEP stands for Medicare Annual Enrollment Period and OEP stands for Medicare Open Enrollment Period. Depending on the context, OEP can refer to many other Medicare enrollment windows.

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Difference Between Medicare AEP vs OEP

The Annual Enrollment Period otherwise referred to as AEP, is the time of year when a Medicare beneficiary can make changes to their current coverage. This enrollment window runs from October 15th to December 7th. Each September before AEP begins, the plan benefit changes for the next year are released, allowing Medicare beneficiaries to look around to ensure they are electing the plan that best fits their needs.

With Medicare Advantage and Part D plan benefits changing every year, premiums could increase, benefits can be changed, and prescription drug formularies can be changed.

Every year in September you will receive an Annual Notice of Change (ANoC) letter. This letter explains all the changes that will be affecting your plan in the upcoming year. The AEP gives you a chance to change if you are not happy with the future adjustments to your plan.

What You Can Do During the Medicare AEP

  • Drop an Advantage Plan and return to Original Medicare
  • Elect to change from one Advantage plan to a different one
  • Change from Original Medicare to an Advantage plan
  • Elect to change from one Part D prescription drug plan to another
  • Cancel your current Part D plan
  • Pick up a Part D plan if you currently do not have one

Any changes you make during the AEP will go into effect on January 1st of the following year.

What Can I Do During the Medicare Open Enrollment Period?

This depends on what OEP you’re referring to. If you’re talking about the AEP, then you can make changes to your current Medicare Advantage or Part D plan.

Those referring to the Medicare Advantage Open Enrollment Period can only make changes if they’re already enrolled in a Medicare Advantage plan.

If you’re referring to your Medicare Supplement Open Enrollment Period, then you can enroll in a Medigap plan without having to answer any health questions.

It’s important to note, you can enroll in a Medigap plan at any point during the year.

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The only difference is if you do it outside your open enrollment window, you’ll have to answer health questions.

How Many Changes Can I Make During the OEP?

Again, this depends on what Open Enrollment Period you’re referring to. If you’re making changes to your Advantage or Part D plan during the AEP, you can make as many changes as you want. The last change you make is what will stick and become effective January 1st of the following year.

If you’re referring to your Medigap OEP, you can also make as many changes as you want. Whichever plan you choose last is what plan you will be enrolled in. It will become effective the 1st of the following month, or as soon as your Part B is active. If you choose to make another change, and you’re still within your 6-month open enrollment window, your plan will become effective on the 1st of the following month.

If you’re talking about the Medicare Advantage Open Enrollment Period, you can only make one change during this enrollment window. So choose wisely the first time!

How to Get Help Understanding the Medicare OEP vs AEP

Due to the confusing enrollment windows and choices you have with Medicare, it's recommended that you speak to a licensed insurance agent that specializes in Medicare. Allow us to lend you our expertise to understand your choices and help you with the enrollment process. Give us a call to speak to a licensed agent, or complete our rate form to compare all Medicare plans available now in your area.

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Jagger Esch

Jagger Esch is the Medicare expert for MedicareFAQ and the founder, president, and CEO of Elite Insurance Partners and Since the inception of his first company in 2012, he has been dedicated to helping those eligible for Medicare by providing them with resources to educate themselves on all their Medicare options. He is featured in many publications as well as writes regularly for other expert columns regarding Medicare.

6 thoughts on “Medicare AEP vs OEP

  1. Ir you have clients with birthdays between October and January who are aging in can you sell them policies between 10/01 and 10/15?

    1. Hi Barbara! Yes, we can lock down the rates early for those aging in. However, the effective date of the policy won’t be until the 1st of the month they are 65 and their Part B is in effect.


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