past the 5th taxable year following such taxable year, determined by treating interest as allowed as a deduction on a first-in, first-out basis. . (2) Treatment of carryforward of disallowed interest in certain corporate acquisitions For rules related to the carryforward of disallowed interest in certain corporate acquisitions, see the amendments made by section 3301(c). (c) Effective date The amendments made by this section shall apply to taxable years beginning after December 31, 2017. 4303. Excise tax on certain payments from domestic corporations to related foreign corporations