(A) such dollar amount, multiplied by (B) the cost-of-living adjustment under section 1(f)(3) for the calendar year in which the taxable year begins, determined by substituting 2019 for 2016 in subparagraph (A)(ii) thereof. If any increase in such $10,000 amount is not a multiple of $100, such increase shall be rounded to the next lowest multiple of $100 and if any increase in such $100,000 amount is not a multiple of $1,000, such increase shall be rounded to the next lowest multiple of $1,000. (3) Rules relating to entities (A) Sole proprietorships If a taxpayer carries on 1 or more trades or businesses as sole proprietorships, all such trades or businesses shall be treated as a single entity for purposes of applying this section. (B) Application to disregarded entities In the case of any entity with a single owner which is disregarded as an entity separate from its owner for purposes of this title, this section shall be applied in the same manner as if such entity were a corporation. (f) Regulations The Secretary shall prescribe such regulations or other guidance as may be necessary to carry out the provisions of this section. . (b) Credit To be part of general business credit Section 38(b) of such Code is amended by striking plus at the end of paragraph (31), by striking the period at the end of paragraph (32) and inserting , plus , and by adding at the end the following new paragraph: (33) the angel investor credit determined under section 45T(a). . (c) Credit allowed against alternative minimum tax Section 38(c)(4)(B) of such Code is amended by redesignating clauses (x), (xi), and (xii) as clauses (xi), (xii), and (xiii), respectively, and by inserting after clause (ix) the following new clause: (x) the credit determined under section 45T, . (d) Clerical amendment The table of sections for subpart D of part IV of subchapter A of chapter 1 of such Code is amended by adding at the end the following new item: Sec. 45T. Angel investor tax credit. . (e) Effective date The amendments made by this section shall