Deductions & credits

Your question is addressed by IRS Notice 2008-59.

Question 41 states:

"Q-41. On what date is an HSA established if the account beneficiary had
previously established an HSA?
A-41. If an account beneficiary establishes an HSA, and later establishes
another HSA, any later HSA is deemed to be established when the first HSA was
established if the account beneficiary has an HSA with a balance greater than zero at
any time during the 18-month period ending on the date the later HSA is established. "

When I first read your question, I remembered the 18-month limit to the gap. However, I was thinking of the wrong 18 months - I was thinking of 18 months after the end of the first HSA and HDHP, but I see now that the text clearly says, "the 18-month period ending on the date the later HSA is established."

Assuming that you still had money in the old HSA in the 18 months prior to when the new HSA was created (it was created on the date that you initially funded it), then the new HSA has the start date of the old HSA and you are good to go.

That is, if you funded the new HSA on January 1, 2022 (for example), then you needed to have a non-zero balance in the old HSA on July 1, 2020 (or later, of course).

However, I do have the concern if you still had money in the old HSA on that date. In my case, the HSA custodian's fees would have drained the account years ago, so that would cause me to fail the 18-month test if I were in the same situation.

[Edited 1/12/2022 | 4:36 PST]