; and (3) by inserting after paragraph (2) the following new paragraph: (3) the taxes imposed by section 1411 of the Internal Revenue Code of 1986 reported to the Secretary of the Treasury or the Secretary’s delegate on tax returns under subtitle F of such Code. . (b) Effective date The amendments made by this section shall apply with respect to taxes imposed for taxable years beginning after December 31, 2023. 3. Application of net investment income tax to trade or business income of certain high income individuals (a) In general Section 1411 of the Internal Revenue Code of 1986 is amended by adding at the end the following new subsection: (f) Application to certain high income individuals (1) In general In the case of any individual whose modified adjusted gross income for the taxable year exceeds the high income threshold amount, subsection (a)(1) shall be applied by substituting the greater of specified net income or net investment income for net investment income in subparagraph (A) thereof. (2) Phase-in of increase The increase in the tax imposed under subsection (a)(1) by reason of the application of paragraph (1) of this subsection shall not exceed the amount which bears the same ratio to the amount of such increase (determined without regard to this paragraph) as— (A) the excess described in paragraph (1), bears to (B) $100,000 ( ½ such amount in the case of a married taxpayer (as defined in section 7703) filing a separate return). (3) High income threshold amount For purposes of this subsection, the term high income threshold amount means— (A) except as provided in subparagraph (B) or (C), $400,000, (B) in the case of a taxpayer making a joint return under section 6013 or a surviving spouse (as defined in section 2(a)), $500,000, and (C) in the case of a married taxpayer (as defined in section 7703) filing a separate return, ½ of the dollar amount determined under subparagraph (B). (4) Specified net income For purposes of this section, the term specified net income means net investment income