terminated by reason of paragraph (1). (B) Special rules For purposes of this subchapter— (i) the determination period with respect to a designation under subparagraph (A) shall be the 90-day period beginning on the date of the enactment of such Act, as extended under subsection (b)(2), and (ii) the period for which any such designation is in effect shall be the period beginning with the date such designation takes effect and ending with the last day of the 10th calendar year beginning on or after the designation date as a qualified opportunity zone for the census tract which it is replacing as such a zone by reason of the termination under clause (i). . (c) Treatment of existing investments Section 1400Z–2(d)(2)(D) of such Code is amended by adding at the end the following new clause: (iv) Special rule for investments in certain census tracts (I) In general For purposes of applying this paragraph, the use of property in a qualified census tract shall be treated as use of property in a qualified opportunity zone if the original use of such property occurred before November 6, 2019, or in the case of property acquired before such date, the property was substantially improved before the close of the 30-month period beginning with the month of the acquisition. (II) Qualified census tract For purposes of this clause, the term qualified census tract means any census tract which is not a low-income community and which was designated as a qualified opportunity zone before the date of the enactment of the Opportunity Zone Reporting and Reform Act . . 4. Maintenance of geographic boundaries of qualified opportunity zones Section 1400Z–1(e) of the Internal Revenue Code of 1986, as redesignated by section 3(a)(2), is amended by adding at the end the following new sentence: Such designation shall apply to the geographic area as in effect at the time such tract is designated without regard to whether adjustments are made to the boundaries of the census tract so designated. . 5. Modification of prohibition on certain types of