Investment in certificates of deposit under AS 37.23.020(6) and the entire amount of principal and interest payable upon maturity of the certificates must be collateralized by a combination of securities that are marked to market at least monthly and have maturity dates that do not exceed five years. Only the following securities may serve as collateral:

(1) obligations of the United States with a maturity date of five years or less after the date of the pool's investment transaction, and with a market value of at least 102 percent;

(2) securities in United States agencies or instrumentalities that are actively traded, other than mortgage pass-through securities, with a maturity date of

(A) one year or less after the date of the pool's investment transaction, and with a market value of at least 103 percent;

(B) more than one year and less than five years after the date of the pool's investment transaction, and with a market value of at least 107 percent;

(3) mortgage pass-through securities issued by the Government National Mortgage Association with a market value of at least 120 percent;

(4) obligations of the state or its political subdivisions secured by the full faith, credit, and taxing power of the state or its political subdivisions, rated A or higher by at least one of the nationally recognized rating services, with a maturity date of

(A) one year or less after the date of the pool's investment transaction, and with a market value of at least 102 percent;

(B) more than one and less than five years after the date of the pool's investment transaction, and with a market value of at least 107 percent.