You should not pay an Income Related Monthly Adjustment Amount (IRMAA) for Medicare Part D if you are
not enrolled in a Medicare Part D plan.
As noted by the Centers for Medicare and Medicaid Services (CMS), "If an individual does not have or no longer has Medicare prescription drug coverage, they shouldn’t be charged the Part D-IRMAA."
However, the CMS memo does continue on to note that "if someone didn’t pay the Part D-IRMAA that was owed before disenrolling from their prescription drug coverage, they are responsible for the past due amount."
(Source: Part D-Income Related Monthly Adjustment Amount—Frequently
Asked Questions & Answers, from Anthony Culotta, Director Medicare
Enrollment & Appeals Group, December 10, 2010)
So if you did not pay your past IRMAA for your Medicare Part D plan coverage, you can still be assessed Part D IRMAA for the unpaid portion or past-due IRMAA - even though you are no longer enrolled in a Medicare Part D plan.
Medicare Part D IRMAA can be charged if you are
enrolled in a Medicare Advantage plan that includes prescription drug
coverage (MAPD). You can click here to read more: https://Q1FAQ.com/654.html
Reminder Part #2:
Even though you may not be subject to Medicare Part D IRMAA, you still may be subject to Medicare Part B IRMAA.
See also: Can I be disenrolled from my Medicare prescription drug plan if I refuse to pay my Medicare Part D IRMAA?
(Spoiler Alert: Yes ...