aggregation rules applicable to S corporations Section 1202(d)(3) is amended by adding at the end the following new subparagraph: (C) Clarification with respect to S corporations Any determination of the members of a controlled group of corporations under this paragraph shall include taking into account any stock ownership in an S corporation. . (4) Treatment of passive losses Section 469(g)(1) is amended by adding at the end the following new subparagraph: (D) Certain dispositions of small business stock In the case a disposition any gain from which is excluded from gross income under section 1202, subparagraph (A) shall not apply. . (5) Special rules relating to S corporations Section 1202(e) is amended by adding at the end the following new paragraph: (9) Applied at S corporation level In the case of an S corporation, the requirements of this subsection shall be applied at the corporate level. . (d) Effective dates (1) In general Except as otherwise provided in this subsection, the amendments made by this section shall apply to stock acquired after the date of the enactment of this Act. (2) Continued treatment as not item of tax preference The amendments made by subsection (a)(3) shall take effect as if included in the enactment of section 2011 the Creating Small Business Jobs Act of 2010. (3) Tacking holding period of convertible debt instruments The amendments made by subsection (b) shall apply to debt instruments originally issued after the date of the enactment of this Act. 5. Increase in limitations on expensing of depreciable business assets (a) In general Section 179(b) is amended— (1) by striking $1,000,000 in paragraph (1) and inserting $2,500,000 , and (2) by striking $2,500,000 in paragraph (2) and inserting $4,000,000 . (b) Inflation adjustment Section 179(b)(6) is amended— (1) by striking 2018 and inserting 2024 (2018 in the case of the dollar amount in paragraph (5)(A)) , and (2) by striking ‘calendar year 2017 and inserting calendar year 2024 ( calendar year 2017 in the case of the dollar