Mississippi Code Title 7. Executive Department § 7-9-27

The treasurer of the state of Mississippi shall invest the moneys deposited in the special fund to refund the overpayment of income taxes under the provisions of Section 27-7-313. The amounts to be invested shall be determined by the treasurer and shall be in the approximate amount of the total moneys deposited in said special fund less the anticipated refunds to be made within the following ninety-day period. Such funds shall be invested by said treasurer in short-term bonds, treasury bills, or other direct obligations of the United States of America, or any national or state banks in the state of Mississippi.