. (2) Conforming amendment Section 172(c) of such Code is amended by inserting before the period at the end the following: and with the reduction required by subsection (g) . (b) Advance refund of research credits and orphan drug credits for C corporation taxpayers Section 39 of such Code is amended by adding at the end the following: (e) Advance refund of research and orphan drug credits (1) In general A taxpayer that is a C corporation may elect an advance refund of the portion of any unused business credit carryforward under section 39 that— (A) is attributable to the credit determined under section 41 or the credit determined under section 45C, and (B) is an unused business credit carryforward carried to a taxable year beginning on or after January 1, 2020, and before January 1, 2022, and that arose in taxable years beginning after January 1, 2015. (2) Limitation The amount elected under paragraph (1) for a taxable year may not exceed the excess of $25,000,000 reduced by the amount elected for the taxable year as an advance refund of net operating loss carryovers under section 172(g). (3) Inapplicability of sections 38(c) and 383(a) For purposes of this subsection, the amount of any advance refund shall be computed without respect to the limitations under sections 38(c) and 383(a). (4) Regulations and guidance The Secretary shall issue such regulations and other guidance as may be necessary— (A) to allow for the making of an election under paragraph (1) in such manner as the Secretary may by regulations prescribe, (B) to allow the advance refund under this subsection and section 6429 based on such information as the Secretary shall require, and (C) to allow advance refunds under this section to be claimed on such forms as the Secretary shall prescribe. . (c) Advance refund of certain net operating losses, research credit, and orphan drug credit (1) In general Subchapter B of chapter 65 of such Code is amended by inserting after section 6428 the following new section: 6429. Advance refund of certain net