Wyo. Stat. § 9-4-106

(a) All state, county, school district, town, city or other public warrants issued for any salary, fee or for any public indebtedness, claim or demand which has accrued on any public contract, transaction or liability shall draw interest upon the amount expressed in the warrant from the date of presentation for payment at the treasury or other place at which the warrant may be payable until there are sufficient funds in the treasury for payment. The rate of interest shall be established by the governmental entity based upon market conditions at the time of presentation of the warrant for payment and shall be stated within the warrant. No rate of interest shall be allowed or paid upon a warrant except as established under this section.

(b) Each state or county treasurer or municipal officer authorized to act as treasurer, to whom a warrant is presented for payment and funds in the treasury are insufficient to pay the warrant, shall endorse the words "not paid, for want of funds" and officially sign and date the warrant.