50 ILCS 45/50

(50 ILCS 45/50) Sec. 50. Late filing penalties. Late filing penalties may not exceed 5% of the amount of tax required to be shown as due on a return. A late filing penalty may not apply if a failure to file penalty is imposed by the unit of local government. A local tax administrator may determine that the late filing was due to reasonable cause and abate the penalty. (Source: P.A. 91-920, eff. 1-1-01.)