Medicare Advantage Open Enrollment Period (OEP)
The Medicare Advantage Open Enrollment Period runs January 1 to March 31. People already in a Medicare Advantage plan can make one change — switch plans or return to Original Medicare with a Part D plan.
Understanding Medicare Advantage Open Enrollment Period (OEP)
The Medicare Advantage Open Enrollment Period (OEP) runs from January 1 to March 31 each year. It is a window specifically for people already enrolled in a Medicare Advantage plan, allowing one change: you can switch to a different Medicare Advantage plan, or drop your Advantage plan and return to Original Medicare (and add a standalone Part D plan).
For beneficiaries, the OEP is a safety net for anyone who realizes after January 1 that their new Advantage plan is not the right fit — for example, a doctor is not in-network or a drug is not covered. It is different from the Annual Enrollment Period: you can only make one change, and it is not for people who have Original Medicare and want to join an Advantage plan for the first time.
For example, if you enrolled in an HMO during AEP and discover in January that your specialist is out-of-network, you can use the OEP to switch to a PPO that includes them.
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Related Terms
Annual Enrollment Period (AEP)
The Annual Enrollment Period runs from October 15 to December 7 each year. During this time, you can switch Medicare Advantage plans, switch to Original Medicare, or change Part D plans.
Medicare Advantage
Medicare Advantage (Part C) is an alternative to Original Medicare offered by private insurance companies approved by Medicare. These plans include Part A, Part B, and usually Part D coverage in one plan.
Special Enrollment Period (SEP)
A Special Enrollment Period is a time outside of the normal enrollment periods when you can make changes to your Medicare coverage due to certain life events like moving or losing other coverage.
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