8 month SEP: MAPD/Part B?


To which circumstances does the 8 month Special Enrollment Period (SEP) apply to?

  1. Enrolling into part B original Medicare
  2. Enrolling into a part D plan
  3. Enrolling into an MAPD plan

Some have come to believe it’s all of the above but that’s not correct. Now, there is a reason why some believe this to be the case and the reason is not surprising at all.

To get straight to the point, the 8 month SEP applies to enrolling into original Medicare part A and/or B when someone disenrolls from a commercial group policy. In the Medicare & You book it states the following on page 23 under the heading Special Enrollment Periods: “If you (or your spouse) are still working, you may have a chance to sign up for Medicare during a Special Enrollment Period. If you didn’t sign up for Part B (or Part A if you have to buy it) when you were
first eligible because you’re covered under a group health plan based on current employment (your own, a spouse’s, or if you’re disabled, a family member’s), you can sign up for Part A and/or Part B:
■ Anytime you’re still covered by the group health plan During the 8-month period that begins the month after the employment ends or the coverage ends, whichever happens first“.

So if we follow this scenario a bit further one would could ask, “when can someone enroll into an MAPD plan if they enrolled into part B using the 8 month SEP?”

The answer is simple, they must apply for the MAPD plan before the part B becomes effective. Here is the “Gotcha!”, if you wait until after part B becomes effective you’ve lost your SEP window to enroll into the MAPD plan. If you don’t qualify for another SEP you would have to wait until the Annual Enrollment Period (AEP) to apply. Let’s use an example to clarify this statement.

Say Mrs. Smith became eligible for Medicare part A and B in August 1st 2015 and chose not to enroll into part B and instead keep her group coverage. Effective January 1st 2017 she decides to retire and thus her group coverage ends 12/31/2016. She was unaware that she could enroll into Medicare part B right after her group coverage ended and so unintentionally delays it an additional four months. But that’s ok, in April she applies for Part B using her SEP (8 month SEP) and is approved for it to become effective May 1st. Now here is the tricky part, before her Part B becomes effective she’s able to apply for an MAPD plan to be effective May 1st. During the month of April she must submit an application for the MAPD plan, if she were to wait until May to apply she would be denied for not having a valid enrollment period.

There are some exceptions to this enrollment deadline, for example if someone were to qualify for another SEP (e.g., LIS, Medicaid), they would be eligible to apply for an MAPD plan every month.

So remember if you delay part B enrollment you must enroll into an MAPD plan before your part B becomes effective otherwise you’ll likely be waiting for the AEP to get another chance to enroll.

There you have it, the 8 month SEP is for Original Medicare after losing group coverage. Oh and if I left you wondering why so many confuse this Medicare SEP with others, well it’s simple: it’s Medicare and it’s all very confusing.


  1. Gabe, If an employer had over 20 employees however effective 07/01 then drop below, how does that effective people on the group that are over age 65?

    1. Kimberly thank you for your question! The answer will depend on when the plan renews their group coverage. Normally the health insurer updates the groups size classification when the group renews its policy. If the renewal period is on a calendar year the employees who are 65 and over, in your scenario, should not be affected because the insurer will not deny any of their claims. Upon the renewal period the insurer will reevaluate the group census and if at that point the group has less than 20 employees the Medicare eligibles should be notified that Medicare is primary. From there on out claims could be denied because of coordination of benefits, the insurer would want Medicare to process the claim first.
      I would like to add that employers are required to report their group size change once they’ve reached 20 consecutive weeks with 20+ employees.

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