30 ILCS 390/13

The State of Illinois is authorized, from time to time as the Governor shall determine, to issue, sell and provide for the retirement of Bonds of the State of Illinois for the sole purpose of refunding all or any portion of the principal of the Bonds; provided that such refunding bonds shall mature no later than the final maturity date of the Bonds being refunded. Such refunding bonds shall in all other respects be subject to the terms and conditions of Sections 4, 5, 7, 8, 9, 10, 11 and 12 of this Act. The principal amount of any such refunding bonds shall not exceed 103% of the principal amount of the Bonds refunded with the proceeds of such refunding Bonds.