used in section 143(k)(2)(B), and (IV) the term nonmetropolitan area means any county (or portion thereof) which is not within a metropolitan statistical area. (v) Buildings designated by State Housing Credit Agency Any building which is designated by the State housing credit agency as requiring the increase in credit under this subparagraph in order for such building to be financially feasible as part of a qualified middle-income housing project shall be treated for purposes of this subparagraph as located in a difficult development area which is designated for purposes of this subparagraph. (5) Credit allowable for certain buildings acquired during 10-year period On application by the taxpayer, the Secretary may waive paragraph (2)(B)(ii) with respect to any building acquired from an insured depository institution in default (as defined in section 3 of the Federal Deposit Insurance Act) or from a receiver or conservator of such an institution. (6) Acquisition of building before end of prior credit period (A) In general Under regulations prescribed by the Secretary, in the case of a building described in subparagraph (B) (or interest therein) which is acquired by the taxpayer— (i) paragraph (2)(B) shall not apply, but (ii) the credit allowable by reason of subsection (a) to the taxpayer for any period after such acquisition shall be equal to the amount of credit which would have been allowable under subsection (a) for such period to the prior owner referred to in subparagraph (B) had such owner not disposed of the building. (B) Description of building A building is described in this subparagraph if— (i) a credit was allowed by reason of subsection (a) to any prior owner of such building, and (ii) the taxpayer acquired such building before the end of the credit period for such building with respect to such prior owner (determined without regard to any disposition by such prior owner). (e) Rehabilitation expenditures treated as separate new building (1) In general Rehabilitation expenditures paid or incurred by