Okla. Stat. tit. 60, § 177.5

All reserve funds currently or hereafter held by any public trust or entity, which funds result from any advance funding or cash management program, must be rebated, with all accrued interest thereon, on a pro rata basis of actual participation to the program participants of the advance funding or cash management program from which the reserve was created unless, within three (3) years of the date of the reserve fund's initial creation, such reserve funds are used by the public trust or entity to fund a similar advance funding or cash management program.