Mississippi Code Title 37. Education § 37-115-35

(a) Bonds, notes, certificates, and other valid obligations of the State of Mississippi, or any county or city of the State of Mississippi, or of any school district bonds of the State of Mississippi;

(b) Bonds, notes, certificates, and other valid obligations of the United States;

(c) Bonds, notes, debentures and other securities issued by any federal instrumentality and fully guaranteed by the United States; or

(d) Interest-bearing bonds or notes which are general obligations of any other state in the United States or of any city or county therein, provided that any such city or county had a population as shown by the federal census next preceding such investment of not less than twenty-five thousand inhabitants, and provided that any such state, city or county has not defaulted for a period longer than thirty days in the payment of principal or interest on any of its general obligation indebtedness during a period of ten calendar years immediately preceding such investment.