@Mike9241
@NCperson
@lb93
A person is ineligible to make HSA contributions once they are "enrolled" in Medicare. Pub 969, page 3, column 2.
The tricky part is figuring out when you are "enrolled." If you enroll during your initial eligibility period (which I think is 3 months before your 65th birthday up to 5 months after your 65th birthdate), your enrollment is effective on the first day of the month in which you turn 65. If you enroll after your initial eligibility period, your enrollment is backdated 6 months (but never before your 65th birthday). This is not specifically described in IRS pub 969 because the IRS does not administer the Medicare rules. The only thing the IRS cares about is that if you are enrolled in Medicare, you can't contribute to an HSA.
If @lb93 received their Medicare card in July 2022 and it is backdated to October 2021, then they are enrolled as of October 2021 (that's the "backdate" rule in action). They aren't further backdated to March 2021. Their contribution limit for 2022 is zero, and they need to remove all 2022 contributions. Their contribution limit for 2021 is $3450 if they were covered by a single HDHP and their limit is $6150 if they were covered by a family HDHP.
I don't have time now to explain the procedure, I can do that tonight if it is still needed.
Also, if @lb93 is married, there may be an opportunity for their spouse to contribute to an HSA if they are covered by an HDHP and are not covered by Medicare, even if the plan is owned by their spouse. (Spouse A can contribute if spouse A is "covered" by a qualifying plan, even if the plan is owned by spouse B.)
