Okla. Stat. tit. 18, § 381.49

With the exception of interest at a rate fixed, or negotiated on an individual basis, by a deposit association prior to the acceptance of the deposit, an association shall determine the rates of earnings to be paid on all classes of deposit accounts, the times and manner of crediting, distributing and paying of such earnings, and the qualifications and limitations applicable to each class of deposit accounts for which a rate higher than regular rate is provided.