§ 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) Credit allowable for exclusion preferences of corporations In the case of a corporation—
(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.
(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.
(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).