Sorry, I misread "Mellon" as "Merrill." Here is the equivalent from NY Mellon's HSA Agreement and Disclosure Statement:
"Prior Year Contributions. Subject to applicable law, we will report to the Internal Revenue Service a contribution to your Account in one year as though made in the previous year only if (a) your deposit is made by April 15, and (b) your deposit is accompanied by our approved form of deposit slip properly completed to indicate that you want that deposit to be credited as a deposit made in the prior year. In the event of employer contribution, the transmittal instructions must indicate a prior year effective date."
<a rel="nofollow" target="_blank" href="
https://mybenefitwallet.com/CMS/docs/default/DADs.pdf">https://mybenefitwallet.com/CMS/docs/default/...>
Under the circumstances, I see no reason that NY Mellon would accommodate a request to re-designate the contribution as being for the prior year and they have no obligation to do so.
