Section 35 ILCS 735/3-5 - Penalty for negligence(a) If any return or amended return is prepared negligently, but without intent to defraud, and filed, in addition to any penalty imposed under Section 3-3 of this Act, a penalty shall be imposed in an amount equal to 20% of any resulting deficiency.(b) Negligence includes any failure to make a reasonable attempt to comply with the provisions of any tax Act and includes careless, reckless, or intentional disregard of the law or regulations.(c) No penalty shall be imposed under this Section if it is shown that failure to comply with the tax Act is due to reasonable cause. A taxpayer is not negligent if the taxpayer shows substantial authority to support the return as filed.(d) If a taxpayer has a tax liability for the taxable period ending after June 30, 1983 and prior to July 1, 2002 that is eligible for amnesty under the Tax Delinquency Amnesty Act and the taxpayer fails to satisfy the tax liability during the amnesty period provided for in that Act for that taxable period, then the penalty imposed by the Department shall be imposed in an amount that is 200% of the amount that would otherwise be imposed in accordance with this Section.(e) If a taxpayer has a tax liability for the taxable period ending after June 30, 2002 and prior to July 1, 2009 that is eligible for amnesty under the Tax Delinquency Amnesty Act, except for any tax liability reported pursuant to Section 506(b) of the Illinois Income Tax Act (35 ILCS 5/506(b)) that is not final, and the taxpayer fails to satisfy the tax liability during the amnesty period provided for in that Act for that taxable period, then the penalty imposed by the Department under this Section shall be imposed in an amount that is 200% of the amount that would otherwise be imposed under this Section.Amended by P.A. 096-1435,§ 20, eff. 8/16/2010.Amended by P.A. 093-0026, § 905, eff. 6/20/2003.