Actually, the new HSA acquires the establishment date of the old HSA as long as there was a nonzero balance in the old HSA at any time in the 18 months prior to the funding of the new HSA. (IRS Notice 2008-59 Q&A-41) In other words, a gap of up to 18 months is permitted. That requirement is certainly met in this case since the old HSA does not yet have a zero balance. Either HSA account can be used to pay for any medical expenses incurred after the old HSA was established.
