Notwithstanding any other provision of law, the board may establish a plan fund, and retain a bank or trust company to serve as repository of the fund. The board may also retain a bank or trust company to serve as a custodian for safekeeping, recordkeeping, delivery, securities valuation, investment performance reporting, or other services in connection with investment of the fund. The board has exclusive control of the administration and investment of the fund. Notwithstanding Section 13340, all moneys in the plan fund are continuously appropriated, without regard to fiscal years, for the purposes of this chapter.