(2) does not apply and which is placed in service by the taxpayer after December 31, 2018, the applicable percentage shall not be less than 4 percent. . (b) Effective date The amendments made by this section shall apply to buildings which receive allocations of housing credit dollar amount or, in the case of projects financed by tax-exempt bonds as described in section 42(h)(4) of the Internal Revenue Code of 1986, which receive a determination of housing credit dollar amount, after the date of the enactment of this Act. 302. Reconstruction or replacement period after casualty loss (a) In general Subparagraph (E) of section 42(j)(4) of the Internal Revenue Code of 1986 is amended by striking a reasonable period established by the Secretary and inserting a reasonable period established by the applicable housing credit agency (not to exceed 25 months from the date on which the casualty loss arises). The determination under paragraph (1) shall not be made with respect to a property the basis of which is affected by a casualty loss until the period described in the preceding sentence with respect to such property has expired. . (b) Effective date The amendment made by this section shall apply to casualty losses arising after the date of the enactment of this Act. 303. Modification and clarification of rights relating to building purchase (a) Modification of right of first refusal Subparagraph (A) of section 42(i)(7) of the Internal Revenue Code of 1986 is amended by striking a right of 1st refusal and inserting an option . (b) Clarification with respect to right of first refusal and purchase options (1) Purchase of partnership interest (A) In general Subparagraph (A) of section 42(i)(7) of the Internal Revenue Code of 1986, as amended by subsection (a), is amended by striking the property and inserting the property or all of the partnership interests (other than interests of the person exercising such option or a related party thereto (within the meaning of section 267(b) or 707(b)(1)) relating to the property . (B)