(a) The board of trustees shall have full power to invest and reinvest the assets of the retirement system and to purchase, hold, sell, assign, transfer, and dispose of any securities and other investments in which assets of the retirement system have been invested, any proceeds of any investments, and any money belonging to the retirement system; provided, however, that such power shall be subject to all terms, conditions, limitations, and restrictions imposed by Article 7 of Chapter 20 of this title, the "Public Retirement Systems Investment Authority Law."

(b) The board of trustees is authorized to employ agents, including, but not limited to, banks or trust departments, and to contract with such agents for their services as investment advisors and counselors who will make recommendations for investments and make investments, if the board of trustees so authorizes.