(1) Except as otherwise provided in this section, there shall be allowed to any person as a credit against the tax imposed by part 3 of this article, for income tax years commencing on or after January 1, 1988, an amount equal to the total of:

(a) Investment tax credit carryovers claimed by such person for such taxable year; and

(b) Ten percent of that part of the credit that would have been allowed for the same income tax year by section 38 of the internal revenue code, as determined under the provisions of subsection (a) of section 46 of the internal revenue code without regard to the limitations imposed by said section 38, had section 49 of the internal revenue code not been enacted, to the extent such part of such credit is determined by reference to property which is used in Colorado. The references in this paragraph (b) to sections 38, 46, and 49 of the internal revenue code mean sections 38, 46, and 49 of the internal revenue code as they existed immediately prior to the enactment of the federal "Revenue Reconciliation Act of 1990".

(2) The executive director shall promulgate regulations which will prescribe the extent to which property must be used in Colorado to qualify for the credit allowed under the provisions of subsection (1) of this section, which regulations shall include a method or methods of determining what portion of the property shall qualify in the case of property which is used both within and without Colorado.

(3) The credit allowed by this section for any income tax year shall not exceed the taxpayer's actual tax liability for the income tax year to the extent that the liability does not exceed one thousand dollars.

(4) In the case of a "controlled group of corporations", as defined in section 1563 (a) of the internal revenue code, the one thousand dollars specified in subsection (3) of this section shall be apportioned among the members of the controlled group as they may elect. The election shall apply to the income tax year of the members of the controlled group ending with or including a common December 31. Should such members fail to agree on an allocation of the one thousand dollars, said one thousand dollars shall be divided equally among all members of the controlled group.

(5) If the amount of the credit allowed by paragraph (b) of subsection (1) of this section exceeds the amount of the limitation imposed by subsection (3) of this section reduced by the credit allowed by paragraph (a) of subsection (1) of this section for any income tax year, referred to in this subsection (5) as the "unused credit year", such excess shall be an investment tax credit carryover to each of the three income tax years following the unused credit year.

(6) The limitations on the credits allowed by this section shall be reduced by any credit allowed by section 39-22-507.5 for the same tax year.