17-5-1641. Investment. (1) Unless otherwise required by a resolution or agreement of the board, the board may invest funds coming under its control pursuant to this part in the same manner as permitted for investment of funds belonging to the state or held by the state treasurer.

(2) Funds from several or all accounts may be combined for investment, and any interest earned shall be prorated and credited to the various contributing accounts on the basis of the amounts thereof invested, calculated according to an average periodic balance or other generally accepted accounting principle. Such proration must be calculated at least once a year or upon a specific request made to the board.

(3) All securities purchased by the board as an investment remain in the custody of the state treasurer until the same are sold, exchanged, retired, or mature and are paid.