The administration of the deferred compensation program for each state agency, department, board, commission, or institution is under the direction of the public employees retirement board. Each county, city, or other political subdivision shall designate an officer to administer the deferred compensation program or appoint the public employees retirement board to administer the program on its behalf. Payroll reductions must be made in each instance by the appropriate payroll officer. The public employees retirement board shall administer the deferred compensation program based on one or more plans in compliance with the appropriate provisions of the Internal Revenue Code and regulations adopted under those provisions. Not later than January 1, 1999, all plan assets and income must be held in trust, custodial accounts, or contracts as described in section 401(f) of the Internal Revenue Code [26 U.S.C. § 401(f)] for the exclusive benefit of participants and their beneficiaries as required by section 457 of the Internal Revenue Code [26 U.S.C. § 457]. Once the trust, custodial account, or contract is established as required by this section, the board shall act as fiduciary of the plan to the extent required by section 457 of the Internal Revenue Code [26 U.S.C. § 457] and the board is authorized to do all things necessary for the proper administration of the plan to ensure that the plan maintains its qualified status.