35 ILCS 5/906 — Further Notices of Deficiency Restricted

Sec. 906. Further Notices of Deficiency Restricted. If a protest has been filed with respect to a notice of deficiency issued by the Department with respect to a taxable year, and the decision of the Department on such protest has become final, the Department shall be barred from issuing a further or additional notice of deficiency for such taxable year, except in the case of fraud, mathematical error, a return that is not considered processable, as the term is defined in Section 3-2 of the Uniform Penalty and Interest Act, or as provided in section 905(d), (e), or (g). (Source: P.A. 89-399, eff. 8-20-95.)