The last Medicare plan enrollment application received before the end of the annual Open Enrollment Period or AEP (the AEP ends on December 7th) determines your Medicare Part D plan or Medicare Advantage plan for the next year.  So: "The last application submitted before midnight, December 7th, wins".

Often we hear: "I enrolled in a Medicare Part D plan during the annual Open Enrollment Period, then, I changed my mind and enrolled in Medicare Advantage plan that includes drug coverage before the AEP ended."  And from our experience, it is fairly common for people to submit more than one Medicare plan enrollment application during the AEP.  Sometimes people make mistakes on their first application --- or they find a Medicare Part D plan or Medicare Advantage plan that they prefer or that provides more affordable prescription and health coverage --- or sometimes people just forget that they enrolled early in the AEP and resubmit an application before receiving the enrollment confirmation or Welcome Letter.

Also, we occasionally hear from people who just can’t say “no” to an advertisement or sales person and enroll in numerous Medicare plans during the Annual Election Period (AEP).

As a note, we do not recommend multiple Medicare plan enrollments.

As you might imagine, people who enroll in several different Medicare Part D plans during the AEP can expect an "avalanche" of New Member or "Welcome" information that will be sent from the different Medicare Part D plan providers.  And sorting through the various Medicare plan information may take some time.

A better idea is to take your time, understand your Medicare plan alternatives and enroll in your chosen plan - only once.

On the positive side, the "last-in-wins" rule allows for added flexibility for early Medicare Part D enrollees who, later in the enrollment period find a more suitable Medicare Part D prescription drug plan or have a change in medications or health that would make another Part D plan or Medicare Advantage plan more affordable or desirable.

Still not sure which Medicare Part D or Medicare Advantage plan will be providing your next year's coverage?

You can always call Medicare at 1-800-633-4227 and a Medicare representative can tell you the name of your currently effective Medicare Part D plan or Medicare Advantage plan - along with the plan contact information.

Where does the Medicare documentation write about "last in" enrollment?

The Medicare Prescription Drug Benefit Manual, Chapter 3 - Eligibility, Enrollment and Disenrollment (2024 version), Section 30.2 – Annual Election Period (AEP), does state:

"There is one AEP enrollment/disenrollment choice available for use during this period. An enrollment/disenrollment election cannot be changed after the end of the AEP." (p.21 PDP Manual)

However, the Medicare Managed Care Manual (for Medicare Advantage plans), Chapter 2 - Medicare Advantage Enrollment and Disenrollment (2024), Section 30.1 - Annual Election Period (AEP), states this information slightly differently:

"During the AEP, MA eligible individuals may enroll in or disenroll from an MA plan. The last enrollment request made, determined by the application date, will be the enrollment request that takes effect (refer to §60.1 for information on multiple transactions)." (p.30 MA Manual)

Strangely enough, it would seem that you can have multiple MA applications with the application having the newest application date as being the chosen plan for January 1st. Whereas, it does not appear the PDPs follow the same convention.

However, in the Medicare Prescription Drug Benefit Manual, Chapter 3 - Eligibility, Enrollment and Disenrollment (2024 version), Section 60.6 – Multiple Transactions:

“Multiple transactions occur when CMS receives more than one enrollment (or disenrollment) request for the same individual with the same effective date in the same reporting period. An individual may not be enrolled in more than one PDP at any given time (however, an individual may be simultaneously enrolled in a cost plan and a separate PDP plan or in certain MA plan types and a separate PDP plan).

Generally, the last enrollment request the beneficiary makes during an enrollment period will be accepted as the PDP into which the individual intends to enroll. If an individual requests enrollment in more than one PDP for the same effective date and with the same application date, the first transaction successfully processed by CMS will take effect. Because simultaneous enrollment in a PDP and certain MA plan types is permitted, CMS systems will accept such enrollments.

Generally, given the use of the application date to determine the intended enrollment choice, retroactive enrollments will not be processed for multiple transactions that reject because enrollment requests have the same application date.” (p.128, PDP Manual)

The MA Enrollment and Disenrollment manual has similar text in section 60.1 – Multiple Transactions:

“Multiple transactions occur when CMS receives more than one enrollment request for the same individual with the same effective date in the same reporting period. An individual may generally not be enrolled in more than one MA, cost, HCPP or PDP plan at any given time (however, an individual may be simultaneously enrolled in a cost plan and a separate PDP plan or in certain MA plan types and a separate PDP plan).

Generally, the last enrollment request the beneficiary makes during an enrollment period will be accepted as the plan into which the individual intends to enroll. If an individual elects more than one plan for the same effective date and with the same application date, the first transaction successfully processed by CMS will take effect. Because simultaneous enrollment in certain MA plan types and a separate PDP is permitted, CMS systems will accept both enrollments.

Generally, given the use of the application date to determine the intended enrollment choice, retroactive enrollments will not be processed for multiple transactions that reject because the enrollment requests have the same application date.” (p.133, MA Manual)

Although the language of Section 30.2 of the 2024 PDP manual does not correspond with the language in and Section 30.1 of the 2024 MA manual, both Section 60.6 of the PDP manual and Section 60.1 of the MA manual anticipate “multiple transactions” were the last enrollment will become the chosen plan (PDP or MA) for the following year.