; or (B) for the establishment of a new, or maintenance of an existing, donor advised fund (as defined in section 4966(d)(2) of such Code). (c) Credit rules (1) Credit treated as nonrefundable personal credit The credit under this section shall be treated as a credit allowed under subpart A of part IV of subchapter A of chapter 1 of the Internal Revenue Code of 1986. (2) Carryforwards of unused credit If the credit allowable under subsection (a) for the taxable year exceeds the limitation imposed by section 26(a) of such Code for such taxable year, reduced by the sum of the credits allowable under such subpart A (other than this section), such excess shall be treated as excess charitable contributions for such year for purposes of section 170 of such Code and carried forward according to the rules of section 170(d)(1) of such Code. (3) Coordination with deduction for charitable contributions Except as provided in paragraph (2), any qualified contribution with respect to which a credit is allowed under subsection (a) shall not be treated as a charitable contribution for purposes of the deduction determined under section 170 of the Internal Revenue Code of 1986.