Can I have a primary HDHP and have a secondary HDHP?

[Macolva]

I am currently covered under my husband's employer-based family HDHP (just us, no other dependents). I have enrolled as a single individual (no dependents, no coverage for husband) in my employer's HDHP for next calendar year (2026) and opted to open an HSA (employer will contribute $500). My spouse currently plans to stay on their employer's HDHP and change from family to individual coverage. 

I am considering staying on my husband's HDHP and continuing his family coverage so that I can use it as secondary insurance.  My questions:

1) Is it legal to be on 2 HDHP plans (one primary and one secondary)?  

2) If I do this, how would we need to manage the HSA contributions? Would I be able to contribute to an HSA at all? Would my husband contribute to the single or family maximum (or does this depend on how much I contribute)?

Thanks in advance! 

[dmertz]

1.  Being covered by a second HDHP does not make you ineligible to contribute to an HSA.

2.  If both spouses are HSA-eligible individuals and at least one is covered by a family HDHP plan, both are treated as covered by a family HDHP plan and are subject to the the combined family contribution limit.  That combined limit can be split between the two of you in any way that you see fit.

[Opus 17]

You would be ineligible if you had "other coverage" that was not an HDHP.So you want to make sure that neither of you gets an FSA at work, for example, unless it is a "limited purpose" FSA that is compatible with an HSA account.  As long as your secondary coverage is also an eligible HDHP,  you are fine.