Okla. Stat. tit. 74, § 920B

A. All participating employers shall remit to the Oklahoma Public Employees Retirement System all required retirement contributions due on a monthly basis. All employee contributions withheld shall be considered trust funds held by the employer on behalf of the employee and shall be promptly remitted to the System pursuant to subsection B of this section. B. For non-state agency employers, all required employer and employee contributions and supporting documentation are due and must be received by the System on or before the fifteenth day of the month following the month for which the contributions are due. For state agency employers, all required employer and employee contributions and supporting documentation are due and must be received by the System on or before the fifteenth day following the last day of the payroll period for which said contributions are due. C. Employer and employee contributions remitted to the System after thirty (30) days from the due dates set forth in subsection B of this section shall be subject to a monthly late charge of three percent (3%) of the unpaid balance to be paid by the employer to the System.