(815 ILCS 137/80)
    Sec. 80. Late payment fee. A lender shall not transfer, deal in, offer, or make a high risk home loan that provides for a late payment fee, except under the following conditions:
        (1) the late payment fee shall not be in excess of 4%
    
of the amount of the payment past due;
        (2) the late payment fee shall only be assessed for a
    
payment past due for 15 days or more;
        (3) the late payment fee shall not be imposed more
    
than once with respect to a single late payment;
        (4) a late payment fee that the lender has collected
    
shall be reimbursed if the borrower presents proof of having made a timely payment; and
        (5) a lender shall treat each payment as posted on
    
the same business day as it was received by the lender, servicer, or lender's agent or at the address provided to the borrower by the lender, servicer, or lender's agent for making payments.
(Source: P.A. 97-849, eff. 1-10-14 (see Section 10 of P.A. 97-1159, 78 Fed. Reg. 6855, 6857, 78 Fed. Reg. 10695, 10696, and 78 Fed. Reg. 44685, 44686).)