(a) By resolutions adopted by the board, an authority may issue bonds to refund all or any outstanding bonds, including matured but unpaid interest coupons. Refunding bonds may mature serially or in any other manner. The bonds may not mature later than 40 years after the date of the bonds. The bonds shall bear interest at a rate that does not exceed the maximum interest rate authorized by Chapter 1204, Government Code.
(b) Refunding bonds may be sold in accordance with Subsection (c) or they may be made payable from the same source as the bonds being refunded or from any additional source. The bonds must be approved by the attorney general in the same manner as original bonds and must be registered by the comptroller of public accounts on the surrender and cancellation of the bonds to be refunded.

(c) The resolution authorizing the issuance of refunding bonds may provide that the bonds be sold and the proceeds deposited where the underlying bonds are payable. If the amount deposited is sufficient to pay the interest and principal on the underlying bonds to their maturity dates, or to their option dates if the bonds have been called for payment before maturity, the authority may issue the refunding bonds before the cancellation of the bonds being refunded, and the comptroller of public accounts shall register the bonds without the surrender and cancellation of the underlying bonds.
(d) Refunding may be accomplished in one or more installment deliveries. Refunding bonds and the appurtenant interest coupons are investment securities under Chapter 8, Business & Commerce Code, and must be issued as provided in this chapter.
(e) In lieu of the method set forth in this section, an authority may refund bonds as provided by general law.