71.08(1)(1) Imposition. If the tax imposed on a natural person, married couple filing jointly, trust or estate under s. 71.02, not considering the credits under ss. 71.07 (1), (2dd), (2de), (2di), (2dj), (2dL), (2dr), (2ds), (2fd), (3m), (6) and (9e), 71.28 (1dd), (1de), (1di), (1dj), (1dL), (1ds), (1fd) and (2m) and 71.47 (1dd), (1de), (1di), (1dj), (1dL), (1ds), (1fd) and (2m) and subchs. VIII and IX and payments to other states under s. 71.07 (7), is less than the tax under this section, there is imposed on that natural person, married couple filing jointly, trust or estate, instead of the tax under s. 71.02, an alternative minimum tax computed as follows:

71.08(1)(a) (a) Adjust the alternative minimum taxable income, as defined in section 55 (b) (2) of the internal revenue code, by the amounts under s. 71.05 (6) to (21), except s. 71.05 (6) (a) 13. and (b) 5. and (8), by the amounts needed to modify federal alternative tax net operating loss deductions to reflect differences between Wisconsin net operating loss deductions and federal net operating loss deductions for minimum tax purposes. The department of revenue shall by rule define Wisconsin net operating loss deductions for minimum tax purposes.

71.08(1)(bm)1. 1. At the time that the incentive stock option is included in alternative minimum taxable income under section 56 (b) (3) of the internal revenue code, subtract from the amount in par. (b) 20% of the amount included in federal alternative minimum taxable income under section 56 (b) (3) of the internal revenue code.

71.08(1)(bm)2. 2. At the time that the stock that was subject to subd. 1. is disposed of, add 20% of the gain or loss adjustment resulting from the basis adjustment made under section 56 (b) (3) of the internal revenue code to the amount in par. (b).

71.08(1)(c) (c) For nonresidents and part-year residents, adjust the amount under par. (bm) so that itemized deductions and personal exemptions are prorated on the basis of the ratio of Wisconsin adjusted gross income to federal adjusted gross income.

71.08(1)(d) (d) Subtract from the amount under par. (c) the appropriate amount under section 55 (d) (1) and (3) of the internal revenue code; except that surviving spouses shall be treated as single individuals; except that the amount under par. (c), not the federal alternative minimum taxable income, shall be used in calculating the phase-out and except that for nonresidents and part-year residents the amount under section 55 (d) (1) and (3) of the internal revenue code shall be prorated on the basis of the ratio of Wisconsin adjusted gross income to federal adjusted gross income.

71.08(2) (2) Joint liability. If the requirements under sub. (1) are applicable and the spouses file a joint income tax return, they shall file a joint minimum tax return and are jointly and severally liable for the tax imposed under sub. (1) and for the interest, penalties, fees, additions to tax and additional assessments with respect to the tax.

71.08(3) (3) Administration. The department of revenue shall have full power to impose, enforce and collect the minimum tax provided in this section and may take any action, conduct any proceeding and in all respects proceed as it is authorized in respect to income taxes imposed in this chapter. The income tax provisions in this chapter relating to assessments, refunds, appeals, collection, interest and penalties shall apply to the minimum tax.

71.08(4) (4) Tax benefit rule. The department of revenue shall promulgate rules to provide that the amount under sub. (1) may be reduced to prevent the inclusion of any amounts, except the federal standard deductions, itemized deductions and personal exemptions, that do not reflect a benefit in respect to the tax imposed under s. 71.02.

71.09(1) (1) Definitions. In this section:

71.09(1)(a) (a) "Farmers or fishers" are individuals, estates or trusts whose estimated gross income from farming or fishing for the taxable year is at least two-thirds of the total estimated gross income from all sources for the taxable year or individuals, estates or trusts whose gross income from farming or fishing for the preceding taxable year was at least two-thirds of the total gross income from all sources shown on that return. If a person files a joint return, the income of both that person and that person's spouse shall be considered in determining whether the person is a farmer or fisher.

71.09(1)(b) (b) "Tax shown on the return" and "tax for the taxable year" mean the net tax imposed under s. 71.02 after reduction for exemptions to, and credits against, that tax but before reduction by amounts withheld under subch. X and before reduction for amounts paid as estimated tax under this section for that tax plus the tax imposed under s. 71.08 before reduction for amounts paid as estimated tax under this section for that tax plus the surcharge imposed under s. 77.93 before reduction for amounts paid as estimated tax under this section for that surcharge.

71.09(2) (2) Who shall pay. Every individual, estate and trust deriving income subject to taxation under this chapter, other than wages as defined in s. 71.63 (6) upon which taxes are withheld by the individual's employer under subch. X, shall pay estimated income tax, the surcharge under s. 77.93 and alternative minimum tax. This section does not apply to any person on active duty with the U.S. armed forces while stationed outside the continental United States. This section does not apply to any taxable year ending before the date 2 years after the date of a decedent's death with respect to the estate of such decedent or any trust all of which is treated under subpart E of part I of subchapter J of chapter 1 of the internal revenue code as owned by the decedent and to which the residue of the decedent's estate will pass under his or her will. This section does not apply to any trust that is subject to tax under this chapter on unrelated business taxable income as defined under section 512 of the internal revenue code. Those trusts are subject to estimated tax payments under s. 71.29.

71.09(3) (3) Farmers or fishers. Payments of estimated income tax required by sub. (2) from farmers or fishers may be made at any time on or before the 15th day of the first month of the succeeding taxable year.

71.09(4) (4) Farmers or fishers exception. Except as provided in sub. (1) (am), if on or before the first day of the 3rd month of the succeeding taxable year a farmer or a fisher files a return for the taxable year, for which estimated taxes were required on or before the 15th day of the first month of the succeeding taxable year under sub. (3), and pays in full the amount computed on the return as payable, then that payment satisfies any required estimated tax instalments.

71.09(5) (5) Amount. The amount of the estimated income tax shall be the total estimated tax, including surtaxes, if any, reduced by the amount, if any, the individual, estate or trust determines will be withheld from wages pursuant to subch. X.

71.09(6) (6) Place of payment. All payments of estimated tax shall be made to the department at its offices in Madison unless the department, by rule, prescribes another place of payment.

71.09(7) (7) Refund carry-forward. If the taxpayer claims a refund on any tax return and, concurrent with or subsequent to the filing of the return upon which such refund is claimed, is required to pay an estimated tax, and at the time of paying that tax the refund has not been paid, he or she may deduct the amount of such refund from the first instalment of estimated taxes, and any excess from the succeeding instalments. If a refund is paid after the due date of the last instalment, its receipt shall be reflected on the income tax return covering the year. If the refund is disallowed in whole or in part after the due date of the last instalment, that disallowance must be reflected on the income tax return covering the year.

71.09(8) (8) Prepayments. Any instalment of the estimated tax under this section may be paid prior to the date prescribed for its payment.

71.09(9) (9) Short year. Application of this section to taxable years of less than 12 full months shall be made pursuant to rules of the department.

71.09(10) (10) Overpayment. When the amount of an instalment payment of estimated tax exceeds the amount determined to be the correct amount of such instalment payment, the overpayment shall be credited against the unpaid instalment, if any.