S.C. Code Ann. § 11-13-30: Only State Treasurer may invest and deposit funds.

To facilitate the management, investment, and disbursement of public funds, no board, commission, agency or officer within the state government, except the State Treasurer shall be authorized to invest and deposit funds from any source, including, but not limited to, funds for which he is custodian, such funds to draw the best rate of interest obtainable.