going Federal rate
(4)(A) in the event any mortgage insured under this section pursuant to a commitment to insure entered into before November 30, 1983 , is not in default at the expiration of twenty years from the date the mortgage was endorsed for insurance, the mortgagee shall, within a period thereafter to be determined by the Secretary, have the option to assign, transfer, and deliver to the Secretary the original credit instrument and the mortgage securing the same and receive the benefits of the insurance as hereinafter provided in this paragraph, upon compliance with such requirements and conditions as to the validity of the mortgage as a first lien and such other matters as may be prescribed by the Secretary at the time the loan is endorsed for insurance. Upon such assignment, transfer, and delivery the obligation of the mortgagee to pay the premium charges for insurance shall cease, and the Secretary shall issue to the mortgagee debentures having a par value equal to the amount of the original principal obligation of the mortgage which was unpaid on the date of the assignment, plus accrued interest to such date. Debentures issued pursuant to this paragraph shall be issued in the same manner and subject to the same terms and conditions as debentures issued under paragraph (1) of this subsection, except that the debentures issued pursuant to this paragraph shall be dated as of the date the mortgage is assigned to the Secretary, shall mature ten years after such date, and shall bear interest from such date at the going Federal rate determined at the time of issuance. The term “going Federal rate” as used herein means the annual rate of interest which the Secretary of the Treasury shall specify as applicable to the six-month period (consisting of January through June or July through December) which includes the issuance date of such debentures, which applicable rate for each such six-month period shall be determined by the Secretary of the Treasury by estimating the average yield to maturity, on the basis of daily closing market bid quotations or prices during the month of May or the month of November, as the case may be, next preceding such six-month period, on all outstanding marketable obligations of the United States having a maturity date of eight to twelve years from the first day of such month of May or November (or, if no such obligations are outstanding, the obligation next shorter than eight years and the obligation next longer than twelve years, respectively, shall be used), and by adjusting such estimated average annual yield to the nearest one-eight of 1 per centum. The Secretary shall have the same authority with respect to mortgages assigned to him under this paragraph as contained in sections 1713(k) and 1713(l) of this title as to mortgages insured by the Secretary and assigned to him under section 1713 of this title .