815 ILCS 130/1

Any bill, memorandum or other statement of account sent to a retail customer who has made a purchase under a revolving charge account where the consideration may be paid either in gross or in a series of monthly installments must set out side by side and with equal prominence both the amount of the total balance owing on the account as well as the amount of the monthly payment due on the account, the annual percentage rate of the total finance charge, interest charge and other charges; and the date by which, or the period (if any) within which, payment must be made in order to avoid additional interest charges or other charges.