I am 69 and will retire on June 30. Until now my medical insurance has been through my employer, and will need go on Medicare beginning July 1. I terminated my health savings account (HSA) last December to avoid penalties when I join Medicare. Today (April 4) I went online and signed up for Medicare, indicating a start date of July 1. The local social security office told me that after I receive my approval letter in a few weeks, I will need to submit forms CMS L564 to prove that I actually have been covered by my employer's insurance, and form CMS 40B to apply for Medicare part B. (My employer already provided me with the L564.) Now, here's the problem: Form 40B requires your Part A medicare number, but in principle I won't have part A Medicare until July 1. (I hope that Medicare actually follows my instructions to begin Parts A and B on July 1, otherwise I am screwed because my HSA ran through last December 31 !) Anyway, the social security office told me to use my social security number instead on Form 40B. Is this correct? Frankly, the people at the social security office seemed clueless in our discussions.

Hi. When you apply for Part A of Medicare coverage more than 6 months after you turn age 65, your Part A coverage automatically starts 6 months prior to the month in which you apply. Unlike Part B of Medicare, you can't pick and choose your start date for Part A of Medicare. So, if you applied for Part A coverage on April 4 2022, your Part A coverage will automatically start effective October 1 2021. If you want your Part A coverage to start later than that, you'll need to withdraw the application you filed (https://www.ssa.gov/forms/ssa-521.pdf) and delay filing until 6 months after the month you want your coverage to begin.

If you actually need to delay your Part A coverage until July 1 2022, the only way you could do so is by waiting to file your application until January 2023. But, if you terminated your HSA in December 2021, then it should be safe to file your application for Part A coverage in July 2022, in which case your coverage will automatically start effective January 1 2022.

I should also note that an application for Social Security retirement benefits is also an application for Part A of Medicare. Therefore, whenever you apply for either retirement benefits or just for Part A coverage separately, your Part A coverage will automatically start 6 months prior to the month in which your application is filed.

You can apply for Part B coverage up to 3 months in advance of the month that you want your coverage to start, so if you want your Part B coverage to start effective July 1st you can apply now. Forms CMS-40B (https://www.cms.gov/Medicare/CMS-Forms/CMS-Forms/Downloads/CMS40B-E.pdf) and CMS-L564 (https://www.cms.gov/Medicare/CMS-Forms/CMS-Forms/Downloads/CMS-L564E.PDF) are the proper forms to use in your case. I'm not positive, but the advice that Social Security gave you about listing your Social Security number as the answer to the question asking for your Medicare number sounds reasonable.

Best, Jerry