Medical sharing arrangements do not make you eligible to contribute to an HSA. They are not considered an HDHP. Part of the reason for this is that with a health sharing arrangement, you are paying someone else’s medical bills, you are not buying insurance that will cover your own bills.
As of last year, the IRS was considering regulations that would allow medical sharing arrangements to be counted as qualifying HDHP‘s, but as far as I know, those regulations have not been approved.
