Mo. Rev. Stat. § 86.107

The board of trustees shall be the trustees of the several funds created by sections 86.010 to 86.193 as provided in section 86.123 and shall have full power to invest and reinvest such funds and shall have full power to hold, purchase, sell, assign, transfer or dispose of any of the securities and investments in which any of the funds created herein shall have been invested, as well as of the proceeds of said investments and any moneys belonging to said funds. The board shall invest the funds of the system as permitted by sections 105.687 to 105.690.