Current year tax credits. A tax credit generated by a member of a combined group is an attribute of the member rather than of the combined group, and credits are to be computed for each taxpayer separately. Therefore, a tax credit earned by a member of the combined group that is not fully used by or allowed to that member shall not be used in either whole or in part by any other member of the combined group or applied in whole or in part against the total income of the combined group.
Tax credit carryforward. A tax credit carryforward of a member of a combined group that was derived from a credit generated by the member either during a year in which the member was subject to combined reporting, or a prior year when the member was not subject to combined reporting, shall not be used in either whole or in part by any other member of the combined group or applied in whole or in part against the total income of the combined group.
D.C. Mun. Regs. tit. 9, r. 9-166