I see this confusion a lot. The IRS specifies the limits for coverage that are considered High Deductible or not. But an employer plan has to be HSA-qualified, as determined by the carrier, when there is to be an HSA offering or provision. A lot of people think, Oh, my plan has a high deductible, so it qualifies. That's not how to judge this.

HSA accounts are never Jointly owned. The funds can be spent on each other and even other people per the IRS medical expense itemization rules, but HSA accounts are per the covered individual. That means a family plan, they would split the HSA limit if they want to. But the catch up amount for age 55 and older must go into the HSA account owned by that person. Am adult child no longer a tax dependent but still covered on the family HSA plan also is eligible for the full Family contribution to their own account.