(1) The department may, by office audit, determine the tax required to be paid to the state or the refund due to any person pursuant to this subchapter. The determination may be made upon the basis of the facts contained in the return being audited or upon the basis of any other information within the department's possession. The determination shall be presumed to be correct and the burden of proving it to be incorrect shall be upon the person challenging the correctness thereof. One or more such office audit determinations may be made of the amount due for any one or for more than one period.
(2) The department may, by field audit, determine the tax required to be paid to the state or the refund due to any person under this subchapter. The determination may be made upon the basis of the facts contained in the return being audited or upon any other information in the department's possession. The determination may be made on the basis of sampling, whether or not the person being audited has complete records of transactions and whether or not the person being audited consents. The department may examine and inspect the books, records, memoranda and property of any person in order to verify the tax liability of that person or of another person. The department may subpoena any person to give testimony under oath before it and to produce whatever books, records or memoranda are necessary in order to enable the department to verify the tax liability of that person or of another person. The determination shall be presumed to be correct and the burden of proving it to be incorrect shall be upon the person challenging its correctness. A determination by the department in a field audit becomes final at the expiration of the appeal periods provided in sub. (6) , and the tax liability of the taxpayer for the period audited may not be subsequently adjusted except as provided in sub. (4) (b) , (8) or (8m) . If the taxpayer files or is required to file more than one return for the taxpayer's fiscal year or for a calendar year, the determination made by field audit for that fiscal or calendar year shall be based on the receipts, purchases, deductions and exemptions for the entire fiscal or calendar year.
(3) No determination of the tax liability of a person may be made unless written notice of the determination is given to the taxpayer within 4 years after the due date of the taxpayer's Wisconsin income or franchise tax return or, if exempt, within 4 years of the 15th day of the 4th month of the year following the close of the calendar or fiscal year, within 4 years of the dissolution of a corporation or within 4 years of the date any sales and use tax return required to be filed for any period in that year was filed, whichever is later. The notice required under this paragraph shall specify whether the determination is an office audit determination or a field audit determination, and it shall be in writing. If the department is unable to obtain service by mail, publication of it as a class 3 notice, under ch. 985 , shall be service of notice in any case where notice is required under this subchapter.
(3m) If the taxpayer has consented in writing to the giving of notice of determination after the time under sub. (3) , the notice may be given, and the taxpayer may file a claim for a refund, at any time prior to the expiration of the period agreed upon. The period so agreed upon may be extended by subsequent agreements in writing.
(4)
(a) Except as provided in sub. (3m) , at any time within 4 years after the due date, or in the case of buyers the unextended due date, of a person's corresponding Wisconsin income or franchise tax return or, if exempt, within 4 years of the 15th day of the 4th month of the year following the close of the calendar or fiscal year for which that person files a claim, that person may, unless a determination by the department by office or field audit of a seller has been made and unless a determination by office audit of a buyer other than an audit in which the tax that is the subject of the refund claim was not adjusted has been made and unless a determination by field audit of the buyer has been made, file with the department a claim for refund of taxes paid to the department by that person. If the amount of the claim is at least $50 or if either the seller has ceased doing business, the buyer is being field audited or the seller may no longer file a claim, the buyer may, within the time period under this subsection, file a claim with the department for a refund of the taxes paid to the seller. A claim is timely if it fulfills the requirements under s. 77.61 (14) . A buyer may claim a refund under this paragraph only on a form prescribed by the department, only by signing that form and only if the seller signs the form unless the department waives that requirement. If both a buyer and a seller file a valid claim for the same refund, the department may pay either claim. The claim for refund shall be regarded as a request for determination. The determination thus requested shall be made by the department within one year after the claim for refund is received by it unless the taxpayer has consented in writing to an extension of the one-year time period prior to its expiration.
(b) A claim for refund that is not to be passed along to customers under sub. (8m) may be made within 2 years of the determination of a tax assessed by office audit or field audit and paid if the tax was not protested by the filing of a petition for redetermination. A claim is timely if it fulfills the requirements under s. 77.61 (14) . No claim may be allowed under this paragraph for any tax self-assessed by the taxpayer. If a claim is filed under this paragraph, the department may make an additional assessment in respect to any item that was a subject of the prior assessment.
(c) A seller who receives a refund under par. (a) or (b) of taxes that the seller has collected from buyers shall return the taxes and related interest to the buyers from whom the taxes were collected. The seller shall return to the department any part of a refund that the seller does not return to a buyer along with a penalty of 25% of the amount not returned or a penalty equal to the amount not returned in the case of fraud.
(5) The department may offset the amount of any refund for a period, together with interest on the refund, against deficiencies for another period, and against penalties and interest on the deficiencies, or against any amount of whatever kind, due and owing on the books of the department from the person claiming the refund. If the refund is to be paid to a buyer, the department may also set off amounts in the manner in which it sets off income tax and franchise tax refunds under s. 71.93 and may set off amounts for child support or maintenance or both in the manner in which it sets off income taxes under ss. 49.855 and 71.93 (3) , (6) and (7) .
(6) Except as provided in sub. (4) (b) , a determination by the department is final unless, within 60 days after receipt of the notice of the determination, the taxpayer, or other person directly interested, petitions the department for a redetermination. A petition is timely if it fulfills the requirements under s. 77.61 (14) . In the case of notice served by publication, the 60-day period commences with the last day of publication of the notice.
(a) Within 6 months of the receipt by the department of the petition for redetermination, the department shall notify the petitioner of its redetermination. The redetermination shall become final 60 days after receipt by the petitioner of notice of the redetermination unless, within that 60-day period, the petitioner appeals the redetermination under par. (b) .
(b) Appeals from the department's redeterminations shall be governed by the statutes applicable to income or franchise tax appeals but all appeals from decisions of the tax appeals commission with respect to the taxes imposed by this subchapter shall be appealed to the circuit court for Dane County.
(c) The department shall notify any person who files a petition for redetermination that the person may deposit the entire deficiency determination, including any penalty or interest, with the department when the petition is filed or at any time before the department makes its redetermination. Any deposited amount which is refunded shall bear interest at the rate of 9% per year during the time the funds were on deposit. A person may also pay any portion of a deficiency determination admitted to be correct and the payment shall be considered an admission of the validity of that portion of the deficiency determination and may not be recovered in an appeal or in any other action or proceeding.
(7) If the department believes that the collection of any tax imposed by this subchapter will be jeopardized by delay, it shall notify the person determined to owe the tax of its intention to proceed under s. 71.91 (5) for collection of the amount determined to be owing, including penalties and interest. Such notice shall be by certified or registered mail or by personal service and the warrant of the department shall not issue if the person, within 10 days after such notice furnishes a bond in such amount not exceeding double the amount determined to be owing and with such sureties as the department approves, conditioned upon the payment of so much of the taxes, interest, and penalties as shall finally be determined to be due. Nothing in this subsection shall affect the review of determinations of tax as provided in this subchapter and any amounts collected under this subsection shall be deposited with the secretary of administration and disbursed after final determination of the taxes as are amounts deposited under ss. 71.89 (1) and 71.90 (2) .
(8) Notwithstanding any other provision of this subchapter, if a person fails to file a report or return required by this subchapter or files a false or fraudulent report or return with the intent in either case to defeat or evade tax required to be paid, the department may determine the proper tax due at any time and without regard to when such failure or filing occurred and without regard to whether a field audit determination was previously made. The department may, at any time, examine and inspect any of the books, records, memoranda, or property of any person and make whatever inquiry, including the subpoena of persons, necessary to the determination of whether a failure to file or a filing was with the intent to defeat or evade the tax.
(8m) Within the time period under sub. (4) , the department of revenue may refund excess taxes paid to it under this chapter, even if the person applying for the refund has been field audited in respect to those taxes, if the applicant's customers have filed valid claims for refunds with the applicant and if the refund is passed along to those customers.
(9) If any person fails to file a return, the department shall make an estimate of the amount of the gross receipts of the person, or, as the case may be, of the amount of the total sales price of tangible personal property or taxable service sold or purchased by the person, the sale by or the storage, use or other consumption of which in this state is subject to sales or use tax. The estimate shall be made for the period in respect to which the person failed to make a return and shall be based upon any information which is in the department's possession or may come into its possession. Upon the basis of this estimate the department shall compute and determine the amount required to be paid to the state, adding to the sum thus arrived at a penalty equal to 25% thereof. One or more such determinations may be made for one or for more than one period. When a business is discontinued a determination may be made at any time thereafter, within the periods specified in sub. (3) , as to liability arising out of that business.
(9m) If the department determines that a liability exists under this subchapter and that the liability may be owed by more than one person, the department may assess the entire amount to each person, specifying that it is assessing in the alternative. If the department determines that a liability exists under this subchapter and that the liability may be for either sales taxes or use taxes, the department may make an assessment for both taxes, specifying that it is assessing in the alternative.
(10) As used in this section, "tax" or "taxes" include penalties and interest.