Mo. Rev. Stat. § 245.235: Unpaid warrants to draw interest.

Any warrant issued under sections 245.010 to 245.280 that is not paid when presented to the treasurer of the board of supervisors of the district, because of lack of funds in the treasury, such fact shall be endorsed on the back of the warrant, and the warrant shall draw interest thereafter at a rate of not more than twelve percent per annum, until such time as there is any money on hand to pay the amount of the warrant and the interest then accumulated, but no interest shall be allowed on warrants after such time when sufficient funds are in the treasury to pay the endorsed warrants and interest.