; and (B) any reference in section 501(o) of the Housing Act of 1949 to the Secretary shall be construed to refer to the FHA to the extent the Secretary has delegated authority under such section 501(o) pursuant to section 552(4). 227. Residual income requirement (a) In general The FHA may not newly insure, under any provision of this title, the National Housing Act, or title V of the Housing Act of 1949, or under any FHA program, any mortgage on a 1- to 4-family residential property unless the mortgagor under such mortgage meets such requirements as the FHA shall, by regulation, establish to ensure that the mortgagor has sufficient residual income. (b) Residual income For purposes of this section, the term residual income means, with respect to a mortgagor, the net monthly income of the mortgagor, as provided by regulation by the FHA, after taking into consideration— (1) any assets of the mortgagor other than the property subject to such mortgage