with respect to any taxable year— (1) at the time of filing the return of the tax imposed by chapter 1 for such taxable year, or (2) at any other time (after the time of filing the return of the tax imposed by chapter 1 for such taxable year) specified in regulations prescribed by the Secretary. Such designation shall be made in such manner as the Secretary prescribes by regulations except that, if such designation is made at the time of filing the return of the tax imposed by chapter 1 for such taxable year, such designation shall be made either on the first page of the return or on the page bearing the taxpayer’s signature. . (b) Border Wall Trust Fund Subchapter A of chapter 98 of such Code (relating to establishment of trust funds) is amended by adding at the end the following new section: 9512. Border Wall Trust Fund (a) Creation of trust fund There is established in the Treasury of the United States a trust fund to be known as the Border Wall Trust Fund , consisting of such amounts as may be appropriated or credited to such fund as provided in this section or section 9602(b). (b) Transfers to trust fund There are hereby appropriated to the Border Wall Trust Fund amounts equivalent to the amounts designated under section 6098. (c) Expenditures Amounts in the Border Wall Trust Fund shall be available, as provided in appropriation Acts, only for the purpose of building a physical wall along the southern border of the United States. . (c) Clerical amendments (1) The table of parts for subchapter A of chapter 61 of such Code is amended by adding at the end the following new item: Part IX. Designation of income tax payments to Border Wall Trust Fund. . (2) The table of sections for subchapter A of chapter 98 of such Code is amended by adding at the end the following new item: Sec. 9512. Border Wall Trust Fund. . (d) Effective date The amendments made by this section shall apply to taxable years beginning after December 31, 2018.