A taxpayer that did not properly report its Illinois taxable income for income tax purposes and did not pay all taxes due during a tax amnesty period was subject to a double interest penalty. The taxpayer qualified for amnesty under the 2003 Amnesty Act, which required the taxpayer to pay all taxes due in order to receive amnesty. The taxpayer paid all taxes due that it had reported on the applicable tax returns, but the taxpayer owed additional unreported taxes that were not paid during the amnesty period based on a federal income tax audit. The trial court initially found in favor of the taxpayer. However, upon appeal by the Department of Revenue to the Appellate Court, the taxpayer’s argument that it was unaware of the additional taxes due at the time of the amnesty program did not move the court. As such, the taxpayer was subject to the double interest penalty. This case addresses the 2003 amnesty program. Since that time, Illinois has held an additional amnesty program with similar double interest and penalty clauses. (Marriott Int’l Inc. v. Hamer, Department of Revenue, Appellate Court of Illinois, First District, No. 1-11-1406, August 22, 2012)