A. The board of trustees shall be the trustees of the several funds of the system and shall have full power to invest and reinvest available funds and to hold, purchase, sell, assign, transfer, and dispose of any of the securities and investments of the system and proceeds thereof provided that the action is taken in compliance with rules and regulations established by the board of trustees and in accordance with the provisions of R.S. 11:263. The board of trustees may adopt rules to further restrict investments of funds.
B. The board of trustees annually shall allow interest on the mean amount for the preceding year in each of the funds except the expense fund and the annuity savings fund. The amount so allowed shall be due and payable to said funds and shall be annually credited thereto by the board from interest and other earnings on the moneys of the retirement system. Any additional amount required to meet the interest on the funds of the retirement system shall be paid from the pension accumulation fund, and any excess of earnings over such amount required shall be paid to the pension accumulation fund. Interest to be allowed shall be determined by the board on the basis of the interest earnings of the system for the preceding year.