(a) The corporation may refund the bonds or any part of them at or before their maturities or redemption dates by the issuance of refunding bonds of the corporation if the state bond rating is the equivalent of AA- or better and if, in the opinion of the corporation, refunding is advantageous to and in the best interest of the state and its inhabitants.
(b) The issuance of refunding bonds need not be authorized by the voters of the state or by an act of the legislature. The corporation shall adopt the resolution or resolutions and prepare all other documents and proceedings necessary for the issuance, exchange or sale, and delivery of the refunding bonds. All provisions of this chapter are applicable to the refunding bonds and to the issuance, sale, or exchange of them, except as otherwise provided in this section.
(c) Refunding bonds may be issued in a principal amount sufficient to provide money for the advance or current refunding of all bonds to be refunded and interest on the refunded bonds and, in addition, for the payment of all costs of issuance and administration of the refunding bonds. These expenses also include the difference in amount between the par value of the refunding bonds and any amount less than par for which the refunding bonds are sold; the premium, if any, necessary to be paid to call or retire the outstanding bonds and the interest accruing on them to the date of the call or retirement; and other of these costs. The corporation is authorized to incur expenses to carry out this section.
(d) The corporation may contract with a refunding trustee to hold the proceeds of refunding bonds in trust until the proceeds, together with earnings on the proceeds, are applied to pay the principal of premium, if any, and interest on the bonds to be refunded. Until the refunding bond proceeds are applied, the proceeds may be invested in direct obligations of, or obligations guaranteed by, the United States or an agency or corporation of the United States whose obligations constitute direct obligations of, or obligations guaranteed by, the United States.