(1) (a) Except as provided in Subsections (2) through (5), the commission shall assess a tax under this chapter within three years after a taxpayer files a return. (b) Except as provided in Subsections (2) through (5), if the commission does not assess a tax under this chapter within the three-year period provided in Subsection (1)(a), the commission may not commence a proceeding to collect the tax.

(a) Except as provided in Subsections (2) through (5), the commission shall assess a tax under this chapter within three years after a taxpayer files a return.

(b) Except as provided in Subsections (2) through (5), if the commission does not assess a tax under this chapter within the three-year period provided in Subsection (1)(a), the commission may not commence a proceeding to collect the tax.

(2) The commission may assess a tax at any time if a taxpayer: (a) files a false or fraudulent return with intent to evade; or (b) does not file a return.

(a) files a false or fraudulent return with intent to evade; or

(b) does not file a return.

(3) The commission may extend the period to make an assessment or to commence a proceeding to collect the tax under this chapter if: (a) the three-year period under Subsection (1) has not expired; and (b) the commission and the taxpayer sign a written agreement: (i) authorizing the extension; and (ii) providing for the length of the extension.

(a) the three-year period under Subsection (1) has not expired; and

(b) the commission and the taxpayer sign a written agreement: (i) authorizing the extension; and (ii) providing for the length of the extension.

(i) authorizing the extension; and

(ii) providing for the length of the extension.

(4) If the commission delays an audit at the request of a taxpayer, the commission may make an assessment as provided in Subsection (5) if: (a) the taxpayer subsequently refuses to agree to an extension request by the commission; and (b) the three-year period under Subsection (1) expires before the commission completes the audit.

(a) the taxpayer subsequently refuses to agree to an extension request by the commission; and

(b) the three-year period under Subsection (1) expires before the commission completes the audit.

(5) An assessment under Subsection (4) shall be: (a) for the time period for which the commission could not make an assessment because of the expiration of the three-year period; and (b) in an amount equal to the difference between: (i) the commission's estimate of the amount of tax the taxpayer would have been assessed for the time period described in Subsection (5)(a); and (ii) the amount of tax the taxpayer actually paid for the time period described in Subsection (5)(a).

(a) for the time period for which the commission could not make an assessment because of the expiration of the three-year period; and

(b) in an amount equal to the difference between: (i) the commission's estimate of the amount of tax the taxpayer would have been assessed for the time period described in Subsection (5)(a); and (ii) the amount of tax the taxpayer actually paid for the time period described in Subsection (5)(a).

(i) the commission's estimate of the amount of tax the taxpayer would have been assessed for the time period described in Subsection (5)(a); and

(ii) the amount of tax the taxpayer actually paid for the time period described in Subsection (5)(a).

(6) (a) Except as provided in Subsection (6)(b), the commission may not make a credit or refund unless the taxpayer files a claim with the commission within three years of the date of overpayment. (b) The commission shall extend the period for a taxpayer to file a claim under Subsection (6)(a) if: (i) the three-year period under Subsection (6)(a) has not expired; and (ii) the commission and the taxpayer sign a written agreement: (A) authorizing the extension; and (B) providing for the length of the extension.

(a) Except as provided in Subsection (6)(b), the commission may not make a credit or refund unless the taxpayer files a claim with the commission within three years of the date of overpayment.

(b) The commission shall extend the period for a taxpayer to file a claim under Subsection (6)(a) if: (i) the three-year period under Subsection (6)(a) has not expired; and (ii) the commission and the taxpayer sign a written agreement: (A) authorizing the extension; and (B) providing for the length of the extension.

(i) the three-year period under Subsection (6)(a) has not expired; and

(ii) the commission and the taxpayer sign a written agreement: (A) authorizing the extension; and (B) providing for the length of the extension.

(A) authorizing the extension; and

(B) providing for the length of the extension.