Okla. Admin. Code § 590:35-5-3
The Recordkeeper shall value the investments each business day. On each Valuation Date, there shall be allocated to the Accounts of each Participant the proportionate share of the increase or decrease in the fair market value of the Participant's Accounts in each of the investments, based on the beginning balance of such Accounts for such day. The Recordkeeper for the Plan may determine the increase or decrease in the fair market value of the Participant's Account in each of the investments on a cash, share or unit accounting basis. Whenever an event requires a determination of the value of the Participant's Accounts, the value shall be computed as of a Valuation Date coincident with or following the date of the event. These daily valuation records shall be maintained by the Recordkeeper for a period of one (1) year. Thereafter, Account information will be available on a quarter-end basis as provided in 590:35-5-1 of these rules.
Okla. Admin. Code § 590:35-5-3