Group returns

If, in computing the net income tax or other business activity tax liability of a person for a taxable year, the net income or other economic results of affiliated persons is taken into account, the portion of such combined or consolidated net income or other economic results that may be subject to tax by the State shall be computed using the methodology that is generally applicable to businesses conducting similar business activities and, if that generally applicable methodology employs an apportionment formula, the denominator or denominators of that formula shall include the aggregate factors of all persons whose net income or other economic results are included in such combined or consolidated net income or other economic results and the numerator or numerators shall include the factors attributable to the State of only those persons that are themselves subject to taxation by the State pursuant to the provisions of this Act and subject to all other legal constraints on State taxation of interstate or foreign commerce.