Wyo. Stat. § 9-4-902

(a) If bonds are issued to refund bonds which are redeemable, the interest rate thereon shall be lower than the rate on the bonds to be refunded. If bonds are issued to refund bonds prior to their redeemable date, the interest rate thereon shall not be greater than that of the outstanding bonds to the redemption date, after which time the interest rate on refunding bonds shall be lower than the rate on the bonds to be refunded.

(b) State refunding bonds shall mature serially, either annually or semiannually, in amounts determined by the governor, state treasurer and attorney general. The first maturity shall be not later than three (3) years and the last maturity not later than fifteen (15) years after the date of the bonds. Principal and interest shall be payable in lawful money of the United States of America at the office of the state treasurer and at other places designated in the bonds. Bonds shall be issued in the denomination of one thousand dollars ($1,000.00) or some multiple thereof and shall be signed by the governor, attested by the secretary of state under the seal of the state, and countersigned by the state treasurer. Semiannual interest coupons to be attached to the bonds shall bear the facsimile signature of the state treasurer. The proceedings for the issuance and the form of the bonds shall be approved by the attorney general, and each bond shall have endorsed thereon a certificate signed by the auditor and secretary of state that the bond is issued pursuant to law and is within the debt limit. Refunding bonds shall be numbered from one (1) upward, and shall be paid in that order. The state treasurer shall keep a record of all bonds issued hereunder in a book to be kept in his office for that purpose.