35 ILCS 120/5
In case any person engaged in the business of selling tangible personal property at retail fails to file a return when and as herein required, but thereafter, prior to the Department's issuance of a notice of tax liability under this Section, files a return and pays the tax, he shall also pay a penalty in an amount determined in accordance with Section 3-3 of the Uniform Penalty and Interest Act.
In case any person engaged in the business of selling tangible personal property at retail files the return at the time required by this Act but fails to pay the tax, or any part thereof, when due, a penalty in an amount determined in accordance with Section 3-3 of the Uniform Penalty and Interest Act shall be added thereto.
In case any person engaged in the business of selling tangible personal property at retail fails to file a return when and as herein required, but thereafter, prior to the Department's issuance of a notice of tax liability under this Section, files a return but fails to pay the entire tax, a penalty in an amount determined in accordance with Section 3-3 of the Uniform Penalty and Interest Act shall be added thereto.
In case any person engaged in the business of selling tangible personal property at retail fails to file a return, the Department shall determine the amount of tax due from him according to its best judgment and information, which amount so fixed by the Department shall be prima facie correct and shall be prima facie evidence of the correctness of the amount of tax due, as shown in such determination. In making any such determination of tax due, it shall be permissible for the Department to show a figure that represents the tax due for any given period of 6 months instead of showing the amount of tax due for each month separately. Proof of such determination by the Department may be made at any hearing before the Department or in any legal proceeding by a reproduced copy or computer print-out of the Department's record relating thereto in the name of the Department under the certificate of the Director of Revenue. If reproduced copies of the Department's records are offered as proof of such determination, the Director must certify that those copies are true and exact copies of records on file with the Department. If computer print-outs of the Department's records are offered as proof of such determination, the Director must certify that those computer print-outs are true and exact representations of records properly entered into standard electronic computing equipment, in the regular course of the Department's business, at or reasonably near the time of the occurrence of the facts recorded, from trustworthy and reliable information. Such certified reproduced copy or certified computer print-out shall, without further proof, be admitted into evidence before the Department or in any legal proceeding and shall be prima facie proof of the correctness of the amount of tax due, as shown therein. The Department shall issue the taxpayer a notice of tax liability for the amount of tax claimed by the Department to be due, together with a penalty of 30% thereof.
However, where the failure to file any tax return required under this Act on the date prescribed therefor (including any extensions thereof), is shown to be unintentional and nonfraudulent and has not occurred in the 2 years immediately preceding the failure to file on the prescribed date or is due to other reasonable cause the penalties imposed by this Act shall not apply.
The taxpayer or the taxpayer's legal representative may, within 60 days after such notice, file a protest to such notice of tax liability with the Department and request a hearing thereon. The Department shall give notice to such person or the legal representative of such person of the time and place fixed for such hearing, and shall hold a hearing in conformity with the provisions of this Act, and pursuant thereto shall issue a final assessment to such person or to the legal representative of such person for the amount found to be due as a result of such hearing. On and after July 1, 2013, protests concerning matters that are under the jurisdiction of the Illinois Independent Tax Tribunal shall be filed with the Illinois Independent Tax Tribunal in accordance with the Illinois Independent Tax Tribunal Act of 2012, and hearings concerning those matters shall be held before the Tribunal in accordance with that Act. With respect to protests filed with the Illinois Independent Tax Tribunal, the Tribunal shall give notice to that person or the legal representative of that person of the time and place fixed for a hearing, and shall hold a hearing in conformity with the provisions of this Act and the Illinois Independent Tax Tribunal Act of 2012; and pursuant thereto the Department shall issue a final assessment to such person or to the legal representative of such person for the amount found to be due as a result of the hearing. With respect to protests filed with the Department prior to July 1, 2013 that would otherwise be subject to the jurisdiction of the Illinois Independent Tax Tribunal, the taxpayer may elect to be subject to the provisions of the Illinois Independent Tax Tribunal Act of 2012 at any time on or after July 1, 2013, but not later than 30 days after the date on which the protest was filed. If made, the election shall be irrevocable.
If a protest to the notice of tax liability and a request for a hearing thereon is not filed within 60 days after such notice, such notice of tax liability shall become final without the necessity of a final assessment being issued and shall be deemed to be a final assessment.
After the issuance of a final assessment, or a notice of tax liability which becomes final without the necessity of actually issuing a final assessment as hereinbefore provided, the Department, at any time before such assessment is reduced to judgment, may (subject to rules of the Department) grant a rehearing (or grant departmental review and hold an original hearing if no previous hearing in the matter has been held) upon the application of the person aggrieved. Pursuant to such hearing or rehearing, the Department shall issue a revised final assessment to such person or his legal representative for the amount found to be due as a result of such hearing or rehearing.
Except in case of failure to file a return, or with the consent of the person to whom the notice of tax liability is to be issued, no notice of tax liability shall be issued on and after each July 1 and January 1 covering gross receipts received during any month or period of time more than 3 years prior to such July 1 and January 1, respectively, except that if a return is not filed at the required time, no notice of tax liability may be issued on and after each July 1 and January 1 for such return filed more than 3 years prior to such July 1 and January 1, respectively . The foregoing limitations upon the issuance of a notice of tax liability shall not apply to the issuance of any such notice with respect to any period of time prior thereto in cases where the Department has, within the period of limitation then provided, notified a person of the amount of tax computed even though the Department had not determined the amount of tax due from such person in the manner required herein prior to the issuance of such notice, but in no case shall the amount of any such notice of tax liability for any period otherwise barred by this Act exceed for such period the amount shown in the notice theretofore issued.
If, when a tax or penalty under this Act becomes due and payable, the person alleged to be liable therefor is out of the State, the notice of tax liability may be issued within the times herein limited after his or her coming into or return to the State; and if, after the tax or penalty under this Act becomes due and payable, the person alleged to be liable therefor departs from and remains out of the State, the time of his or her absence is no part of the time limited for the issuance of the notice of tax liability; but the foregoing provisions concerning absence from the State shall not apply to any case in which, at the time when a tax or penalty becomes due under this Act, the person allegedly liable therefor is not a resident of this State.
The time limitation period on the Department's right to issue a notice of tax liability shall not run during any period of time in which the order of any court has the effect of enjoining or restraining the Department from issuing the notice of tax liability.
In case of failure to pay the tax, or any portion thereof, or any penalty provided for in this Act, or interest, when due, the Department may bring suit to recover the amount of such tax, or portion thereof, or penalty or interest; or, if the taxpayer has died or become a person under legal disability, may file a claim therefor against his estate; provided that no such suit with respect to any tax, or portion thereof, or penalty, or interest shall be instituted more than 6 years after the date any proceedings in court for review thereof have terminated or the time for the taking thereof has expired without such proceedings being instituted, except with the consent of the person from whom such tax or penalty or interest is due; nor, except with such consent, shall such suit be instituted more than 6 years after the date any return is filed with the Department in cases where the return constitutes the basis for the suit for unpaid tax, or portion thereof, or penalty provided for in this Act, or interest: Provided that the time limitation period on the Department's right to bring any such suit shall not run during any period of time in which the order of any court has the effect of enjoining or restraining the Department from bringing such suit.
After the expiration of the period within which the person assessed may file an action for judicial review under the Administrative Review Law or the Illinois Independent Tax Tribunal Act of 2012, as applicable, without such an action being filed, a certified copy of the final assessment or revised final assessment of the Department may be filed with the Circuit Court of the county in which the taxpayer has his principal place of business, or of Sangamon County in those cases in which the taxpayer does not have his principal place of business in this State. The certified copy of the final assessment or revised final assessment shall be accompanied by a certification which recites facts that are sufficient to show that the Department complied with the jurisdictional requirements of the Act in arriving at its final assessment or its revised final assessment and that the taxpayer had his opportunity for an administrative hearing and for judicial review, whether he availed himself or herself of either or both of these opportunities or not. If the court is satisfied that the Department complied with the jurisdictional requirements of the Act in arriving at its final assessment or its revised final assessment and that the taxpayer had his opportunity for an administrative hearing and for judicial review, whether he availed himself of either or both of these opportunities or not, the court shall render judgment in favor of the Department and against the taxpayer for the amount shown to be due by the final assessment or the revised final assessment, plus any interest which may be due, and such judgment shall be entered in the judgment docket of the court. Such judgment shall bear the rate of interest as set by the Uniform Penalty and Interest Act, but otherwise shall have the same effect as other judgments. The judgment may be enforced, and all laws applicable to sales for the enforcement of a judgment shall be applicable to sales made under such judgments. The Department shall file the certified copy of its assessment, as herein provided, with the Circuit Court within 6 years after such assessment becomes final except when the taxpayer consents in writing to an extension of such filing period, and except that the time limitation period on the Department's right to file the certified copy of its assessment with the Circuit Court shall not run during any period of time in which the order of any court has the effect of enjoining or restraining the Department from filing such certified copy of its assessment with the Circuit Court.
If, when the cause of action for a proceeding in court accrues against a person, he or she is out of the State, the action may be commenced within the times herein limited, after his or her coming into or return to the State; and if, after the cause of action accrues, he or she departs from and remains out of the State, the time of his or her absence is no part of the time limited for the commencement of the action; but the foregoing provisions concerning absence from the State shall not apply to any case in which, at the time the cause of action accrues, the party against whom the cause of action accrues is not a resident of this State. The time within which a court action is to be commenced by the Department hereunder shall not run from the date the taxpayer files a petition in bankruptcy under the Federal Bankruptcy Act until 30 days after notice of termination or expiration of the automatic stay imposed by the Federal Bankruptcy Act.
No claim shall be filed against the estate of any deceased person or any person under legal disability for any tax or penalty or part of either, or interest, except in the manner prescribed and within the time limited by the Probate Act of 1975, as amended.
The collection of tax or penalty or interest by any means provided for herein shall not be a bar to any prosecution under this Act.
In addition to any penalty provided for in this Act, any amount of tax which is not paid when due shall bear interest at the rate and in the manner specified in Sections 3-2 and 3-9 of the Uniform Penalty and Interest Act from the date when such tax becomes past due until such tax is paid or a judgment therefor is obtained by the Department. If the time for making or completing an audit of a taxpayer's books and records is extended with the taxpayer's consent, at the request of and for the convenience of the Department, beyond the date on which the statute of limitations upon the issuance of a notice of tax liability by the Department otherwise would run, no interest shall accrue during the period of such extension or until a Notice of Tax Liability is issued, whichever occurs first.
In addition to any other remedy provided by this Act, and regardless of whether the Department is making or intends to make use of such other remedy, where a corporation or limited liability company registered under this Act violates the provisions of this Act or of any rule or regulation promulgated thereunder, the Department may give notice to the Attorney General of the identity of such a corporation or limited liability company and of the violations committed by such a corporation or limited liability company, for such action as is not already provided for by this Act and as the Attorney General may deem appropriate.
If the Department determines that an amount of tax or penalty or interest was incorrectly assessed, whether as the result of a mistake of fact or an error of law, the Department shall waive the amount of tax or penalty or interest that accrued due to the incorrect assessment.
35 ILCS 120/5