(3) Qualified mortgage The term “qualified mortgage” means— (A) any obligation (including any participation or certificate of beneficial ownership therein) which is principally secured by an interest in real property and which— (i) is transferred to the REMIC on the startup day in exchange for regular or residual interests in the REMIC, (ii) is purchased by the REMIC within the 3-month period beginning on the startup day if, except as provided in regulations, such purchase is pursuant to a fixed-price contract in effect on the startup day, or (iii) represents an increase in the principal amount under the original terms of an obligation described in clause (i) or (ii) if such increase— (I) is attributable to an advance made to the obligor pursuant to the original terms of a reverse mortgage loan or other obligation, (II) occurs after the startup day, and (III) is purchased by the REMIC pursuant to a fixed price contract in effect on the startup day, (B) any qualified replacement mortgage, and (C) any regular interest in another REMIC transferred to the REMIC on the startup day in exchange for regular or residual interests in the REMIC. For purposes of subparagraph (A), any obligation secured by stock held by a person as a tenant-stockholder (as defined in section 216) in a cooperative housing corporation (as so defined) shall be treated as secured by an interest in real property. For purposes of subparagraph (A), any obligation originated by the United States or any State (or any political subdivision, agency, or instrumentality of the United States or any State) shall be treated as principally secured by an interest in real property if more than 50 percent of such obligations which are transferred to, or purchased by, the REMIC are principally secured by an interest in real property (determined without regard to this sentence).
26 USC § 860G(a)(3)
None identified. Default scope is assumed to be the entire title.