The State Treasurer shall invest all sinking fund monies in direct obligations of the United States of America or in certificates of deposits from banks in the State of Oklahoma acceptable as depositories by the State Treasurer when such certificates of deposits are secured by acceptable collateral and yield as much or more than direct obligations of the United States of America, to mature in time to meet the principal and interest payments on the State of Oklahoma Institutional Building Bonds of 1965, which earnings shall be deposited in the sinking fund.
Okla. Stat. tit. 62, § 57.70