Ill. Admin. Code tit. 74, § 900.40
a) The remittance advice of each commercial payment must contain the following statement or words of similar meaning:
"Payment of interest may be available if the State fails to comply with the State Prompt Payment Act [30 ILCS 540]."
(Source: Amended at 26 Ill. Reg. 14666, effective September 19, 2002)