1 53 Credit for prior year minimum tax liability a Allowance of credit There shall be allowed as a credit against the tax imposed by this chapter for any taxable year an amount equal to the minimum tax credit for such taxable year b Minimum tax credit For purposes of subsection a the minimum tax credit for any taxable year is the excess if any of 1 the adjusted net minimum tax imposed for all prior taxable years beginning after 1986 over 2 the amount allowable as a credit under subsection a for such prior taxable years c Limitation The credit allowable under subsection a for any taxable year shall not exceed the excess if any of 1 the regular tax liability of the taxpayer for such taxable year reduced by the sum of the credits allowable under subparts A B D E and F of this part over 2 the tentative minimum tax for the taxable year d Definitions For purposes of this section 1 Net minimum tax A In general The term net minimum tax means the tax imposed by section 55 B Credit not allowed for exclusion preferences i Adjusted net minimum tax The adjusted net minimum tax for any taxable year is I the amount of the net minimum tax for such taxable year reduced by II the amount which would be the net minimum tax for such taxable year if the only adjustments and items of tax preference taken into account were those specified in clause ii ii Specified items The following are specified in this clause I the adjustments provided for in subsection b 1 of section 56 and II the items of tax preference described in paragraphs 1 5 and 7 of section 57 a iii Special rule The adjusted net minimum tax for the taxable year shall be increased by the amount of the credit not allowed under section 30 solely by reason of the application of section 30 b 3 B iv Credit allowable for exclusion preferences of corporations In the case of a corporation 2 I the preceding provisions of this subparagraph shall not apply and II the adjusted net minimum tax for any taxable year is the amount of the net minimum tax for such year increased in the manner provided in clause iii 2 Tentative minimum tax The term tentative minimum tax has the meaning given to such term by section 55 b e Special rule for individuals with long term unused credits 1 In general If an individual has a long term unused minimum tax credit for any taxable year beginning before January 1 2013 the amount determined under subsection c for such taxable year shall not be less than the AMT refundable credit amount for such taxable year 2 AMT refundable credit amount For purposes of paragraph 1 the term AMT refundable credit amount means with respect to any taxable year the amount not in excess of the long term unused minimum tax credit for such taxable year equal to the greater of A 50 percent of the long term unused minimum tax credit for such taxable year or B the amount if any of the AMT refundable credit amount determined under this paragraph for the taxpayer s preceding taxable year determined without regard to subsection f 2 3 Long term unused minimum tax credit A In general For purposes of this subsection the term long term unused minimum tax credit means with respect to any taxable year the portion of the minimum tax credit determined under subsection b attributable to the adjusted net minimum tax for taxable years before the 3rd taxable year immediately preceding such taxable year B First in first out ordering rule For purposes of subparagraph A credits shall be treated as allowed under subsection a on a first in first out basis 4 Credit refundable For purposes of this title other than this section the credit allowed by reason of this subsection shall be treated as if it were allowed under subpart C f Treatment of certain underpayments interest and penalties attributable to the treatment of incentive stock options 1 Abatement Any underpayment of tax outstanding on the date of the enactment of this subsection which is attributable to the application of section 56 b 3 for any taxable year ending before January 1 2008 and any interest or penalty with respect to such underpayment which is outstanding on such date of enactment is hereby abated The amount determined under subsection b 1 shall not include any tax abated under the preceding sentence 3 2 Increase in credit for certain interest and penalties already paid The AMT refundable credit amount and the minimum tax credit determined under subsection b for the taxpayer s first 2 taxable years beginning after December 31 2007 shall each be increased by 50 percent of the aggregate amount of the interest and penalties which were paid by the taxpayer before the date of the enactment of this subsection and which would but for such payment have been abated under paragraph 1 55 Alternative minimum tax imposed a General rule There is hereby imposed in addition to any other tax imposed by this subtitle a tax equal to the excess if any of 1 the tentative minimum tax for the taxable year over 2 the regular tax for the taxable year b Tentative minimum tax For purposes of this part 1 Amount of tentative tax A Noncorporate taxpayers i In general In the case of a taxpayer other than a corporation the tentative minimum tax for the taxable year is the sum of I 26 percent of so much of the taxable excess as does not exceed 175 000 plus II 28 percent of so much of the taxable excess as exceeds 175 000 The amount determined under the preceding sentence shall be reduced by the alternative minimum tax foreign tax credit for the taxable year ii Taxable excess For purposes of this subsection the term taxable excess means so much of the alternative minimum taxable income for the taxable year as exceeds the exemption amount iii Married individual filing separate return In the case of a married individual filing a separate return clause i shall be applied by substituting 87 500 for 175 000 each place it appears For purposes of the preceding sentence marital status shall be determined under section 7703 B Corporations In the case of a corporation the tentative minimum tax for the taxable year is i 20 percent of so much of the alternative minimum taxable income for the taxable year as exceeds the exemption amount reduced by 4 ii the alternative minimum tax foreign tax credit for the taxable year 2 Alternative minimum taxable income The term alternative minimum taxable income means the taxable income of the taxpayer for the taxable year A determined with the adjustments provided in section 56 and section 58 and B increased by