Tenn. Code § 65-162
The board of trustees shall be the trustee of the public service commissioners' retirement fund created by § 65-161 and shall have the full power to invest and reinvest all moneys comprising the fund to the extent that the board deems appropriate, subject to the limitation that no investment shall be made except on the exercise of bona fide discretion, in securities which, at the time of making the investment are, by statute, permitted for the investment of funds of the Tennessee state retirement system, as established by §§ 8-3401 - 8-3516. Subject to such limitations, the board shall have the full power to hold, purchase, sell, assign, transfer, or dispose of any of the securities or investment in which the public service commissioners' retirement fund created by § 65-161 has been invested, as well as the proceeds of such investments and the moneys belonging to the said fund. The state treasurer shall be the custodian of the fund. All payments from the fund shall be authorized by the state treasurer on vouchers requested by the board of trustees and duly issued by the state treasurer.
T.C.A. § 65-162