Example. Housing Authority X issues bonds intended to be qualified mortgage bonds under section 143(a). At the time the bonds are issued, X enters into an agreement with a group of mortgage lending institutions (lenders) under which the lenders agree to originate and service mortgages that meet certain specified requirements. After originating a specified amount of mortgages, each lender issues a "pass-though security" (each, a PTS) backed by the mortgages and sells the PTS to X. Under the terms of the PTS, the lender pays X an amount equal to the regular monthly payments on the mortgages (less certain fees), whether or not received by the lender (plus any prepayments and liquidation proceeds in the event of a foreclosure or other disposition of any mortgages). FNMA guarantees the timely payment of principal and interest on each PTS. From the payments received from each mortgagor, the lender pays a fee to FNMA for its guarantee of the PTS. The amounts paid to FNMA do not exceed the amounts charged in the area with respect to a similar pool of mortgages that is not financed with mortgage revenue bonds. Under this paragraph (b)(2)(iii), the fees for the guarantee provided by FNMA are an insurance charge because the guarantee is pool mortgage insurance. Because the amounts charged for the guarantee do not exceed the amounts charged in the area with respect to a similar pool of mortgages that is not financed with mortgage revenue bonds, the amounts charged for the guarantee are not taken into account in computing the effective rate of interest on the mortgages financed with X's bonds.
26 C.F.R. §1.143(g)-1