Okla. Stat. tit. 19, § 637

The county commissioners may require the county treasurer to give additional securities whenever in the opinion of a majority of said county commissioners, the existing security shall have become insufficient and said commissioners are hereby also authorized and empowered to demand and receive from said county treasurer an additional bond as required by law, with good and sufficient security in such sum as said commissioners or a majority of them may direct whenever in their opinion more money shall have passed or is about to pass into the hands of said treasurer than is or would be recovered by the penalty on the previous bond.