A computer-implemented arrangement facilitates purchases by multiple cardmembers using respective transaction instruments, each transaction instrument being associated with a single tax-advantaged account. A merchant's requested payment from a point of sale device for a purchase by a cardmember against the tax-advantaged account is received by a host computer system, which determines whether the requested charge is associated with a tax-advantaged qualified expense. The tax-advantaged account is credited with points associated with the value of the charge only if the charge is determined to be for a covered tax-advantaged expense. This process occurs for all other cardmembers making transactions associated with the same tax-advantaged account.