The Corporation shall file with the President and with the Congress in December of each year a financial statement and complete report as to the expenditure of funds derived from the sale of bonds under this section covering the period not covered by any such previous statement or report. Such bonds shall be in such forms and denominations, shall mature within such periods not more than fifty years from the date of their issue, may be redeemable at the option of the Corporation before maturity in such manner as may be stipulated therein, shall bear such rates of interest not exceeding 31/2 per centum per annum, shall be subject to such terms and conditions, shall be issued in such manner and amount, and sold at such prices, as may be prescribed by the Corporation with the approval of the Secretary of the Treasury: Provided, That such bonds shall not be sold at such prices or on such terms as to afford an investment yield to the holders in excess of 31/2 per centum per annum. Such bonds shall be fully and unconditionally guaranteed both as to interest and principal by the United States, and such guaranty shall be expressed on the face thereof, and such bonds shall be lawful investments, and may be accepted as security, for all fiduciary, trust, and public funds, the investment or deposit of which shall be under the authority or control of the United States or any officer or officers thereof. In the event that the Corporation should not pay upon demand when due, the principal of, or interest on, such bonds, the Secretary of the Treasury shall pay to the holder the amount thereof, which is authorized to be appropriated out of any moneys in the Treasury not otherwise appropriated, and thereupon to the extent of the amount so paid the Secretary of the Treasury shall succeed to all the rights of the holders of such bonds. The Secretary of the Treasury, in his discretion, is authorized to purchase any bonds issued hereunder, and for such purpose the Secretary of the Treasury is authorized to use as a public-debt transaction the proceeds from the sale of any securities hereafter issued under chapter
, and the purposes for which securities may be issued under such chapter are extended to include any purchases of the Corporation’s bonds hereunder. The Secretary of the Treasury may, at any time, sell any of the bonds of the Corporation acquired by him under this section. All redemptions, purchases, and sales by the Secretary of the Treasury of the bonds of the Corporation shall be treated as public-debt transactions of the United States. With the approval of the Secretary of the Treasury, the Corporation shall have power to purchase such bonds in the open market at any time and at any price. None of the proceeds of the bonds shall be used for the performance of any proposed contract negotiated by the Corporation under the authority of section
of this title until the proposed contract shall have been submitted to and approved by the Federal Power Commission. When any such proposed contract shall have been submitted to the said Commission, the matter shall be given precedence and shall be in every way expedited and the Commission’s determination of the matter shall be final. The authority of the Corporation to issue bonds under this section shall expire January 1, 1941, except that if at the time such authority expires the amount of bonds issued by the Corporation under this section is less than $61,500,000, the Corporation may, subject to the foregoing provisions of this section, issue, after the expiration of such period, bonds in an amount not in excess of the amount by which the bonds so issued prior to the expiration of such period is less than $61,500,000, for refunding purposes, or, subject to the provisions of paragraph (5) of this section (limiting the purposes for which loans under section
of this title of funds derived from bonds proceeds may be made) to provide funds found necessary in the performance of any contract entered into by the Corporation prior to the expiration of such period, under the authority of section
of this title.