In the case of an affiliated group of corporations engaged in a unitary business with activity taxable both within and without this State, the rates provided in this subsection are applied only to the first $250,000 of the net income of the entire group and must be apportioned equally among the taxable corporations unless those taxable corporations jointly elect a different apportionment. The balance of the net income of the entire group is taxed at 8.93%.

2.__Business activity only within Maine.__For purposes of subsection 1, with respect to a taxable corporation or group of corporations that derive income from a unitary business carried on by 2 or more members of an affiliated group with income from business activity that is taxable only by Maine, "income" means Maine net income.

3.__Business activity within and outside Maine.__For purposes of subsection 1, with respect to a taxable corporation with income from business activity that is taxable both within and without this State, "income" means the corporation's net income.__ The tax amount computed under subsection 1 must then be apportioned under the provisions of chapter 821 to determine the amount of tax imposed on that corporation.

4.__Business activity within and outside Maine; unitary business.__For purposes of subsection 1, with respect to taxable corporations that derive income from a unitary business carried on by 2 or more members of an affiliated group with business activity that is taxable both within and without this State, "income" means the net income of the entire group.__The tax amount computed under subsection 1 must then be apportioned under the provisions of chapter 821 for the entire group to determine the amount of tax imposed on the taxable corporations.

5. Net income.__For purposes of this section, "net income" means, for any taxable year, the taxable income of the taxpayer for that taxable year under the laws of the United States as modified by section 5200-A.

6.__Taxable in another state.__For purposes of this section, a taxpayer is taxable in another state if in that state the taxpayer is subject to a net income tax, a franchise tax measured by net income, a franchise tax for the privilege of doing business, or a corporate stock tax, or that state has jurisdiction to subject the taxpayer to a net income tax regardless of whether, in fact, the state does or does not.