(a) For purposes of this chapter:
(1) “Resident of this state” means any natural person (A) who is domiciled in this state, unless (i) the person maintains no permanent place of abode in this state, maintains a permanent place of abode elsewhere and spends in the aggregate not more than thirty days of the taxable year in this state, or (ii) within any period of five hundred forty-eight consecutive days the person is present in a foreign country or countries for at least four hundred fifty days, and during such period of five hundred forty-eight consecutive days the person is not present in this state for more than ninety days and does not maintain a permanent place of abode in this state at which such person's spouse, unless such spouse is legally separated, or minor children are present for more than ninety days, and during the nonresident portion of the taxable year with or within which such period of five hundred forty-eight consecutive days begins and the nonresident portion of the taxable year with or within which such period ends, such person is present in this state for a number of days which does not exceed an amount which bears the same ratio to ninety as the number of days contained in such portion of the taxable year bears to five hundred forty-eight, or (B) who is not domiciled in this state but maintains a permanent place of abode in this state and is in this state for an aggregate of more than one hundred eighty-three days of the taxable year, unless such person, not being domiciled in this state, is in active service in the armed forces of the United States.
(2) “Nonresident of this state” means any natural person who is not a resident of this state for any portion of the taxable year.
(3) “Part-year resident of this state” means any natural person who is not either a resident of this state for the entire taxable year or a nonresident of this state for the entire taxable year.
(4) “Resident trust or estate” means (A) the estate of a decedent who at the time of his death was a resident of this state, (B) the estate of a person who, at the time of commencement of a case under Title 11 of the United States Code, was a resident of this state, (C) a trust, or a portion of a trust, consisting of property transferred by will of a decedent who at the time of his death was a resident of this state, and (D) a trust, or a portion of a trust, consisting of the property of (i) a person who was a resident of this state at the time the property was transferred to the trust if the trust was then irrevocable, (ii) a person who, if the trust was revocable at the time the property was transferred to the trust, and has not subsequently become irrevocable, was a resident of this state at the time the property was transferred to the trust or (iii) a person who, if the trust was revocable when the property was transferred to the trust but the trust has subsequently become irrevocable, was a resident of this state at the time the trust became irrevocable. For purposes of this chapter, if any trust or portion of a trust, other than a trust created by the will of a decedent, has one or more nonresident noncontingent beneficiaries, the Connecticut taxable income of the trust, as defined in subdivision (9) of this subsection, shall be modified as follows: The Connecticut taxable income of the trust shall be the sum of all such income derived from or connected with sources within this state and that portion of such income derived from or connected with all other sources which is derived by applying to all such income derived from or connected with all other sources a fraction the numerator of which is the number of resident noncontingent beneficiaries and the denominator of which is the total number of noncontingent beneficiaries. For purposes of section 12-700a , if any trust or portion of a trust, other than a trust created by the will of a decedent, has one or more nonresident noncontingent beneficiaries, its adjusted federal alternative minimum taxable income, as defined in section 12-700a shall be modified as follows: The adjusted federal alternative minimum taxable income of the trust shall be the sum of all such income derived from or connected with sources within this state and that portion of such income derived from or connected with all other sources which is derived by applying to all such income derived from or connected with all other sources a fraction, the numerator of which is the number of resident noncontingent beneficiaries and the denominator of which is the total number of noncontingent beneficiaries. As used in this subdivision, “noncontingent beneficiary” means a beneficiary whose interest is not subject to a condition precedent.
(5) “Nonresident trust or estate” means any trust or estate other than a resident trust or estate or a part-year resident trust.
(6) “Part-year resident trust” means any trust which is not either a resident trust or a nonresident trust for the entire taxable year.
(7) “Taxable year” means taxable year as determined in accordance with section 12-708 .
(8) “Connecticut taxable income of a resident” means the Connecticut adjusted gross income of a natural person with respect to any taxable year reduced by the amount of the exemption provided in section 12-702 .
(9) “Connecticut taxable income of a resident trust or estate” means the taxable income of the fiduciary of such trust or estate as determined for purposes of the federal income tax, to which (A) there shall be added or subtracted, as the case may be, the share of the trust or estate, as determined under section 12-716 , in the Connecticut fiduciary adjustment, and (B) with respect to any trust, there shall be added the amount of any includable gain, reduced by any deductions properly allocable thereto, upon which a tax is imposed for the taxable year pursuant to Section 644 of the Internal Revenue Code.
(10) “Connecticut fiduciary adjustment” means the net positive or negative total of the following items relating to income, gain, loss or deduction of a trust or estate:
(A) There shall be added together:
(i) Any interest income from obligations issued by or on behalf of any state, political subdivision thereof, or public instrumentality, state or local authority, district or similar public entity, exclusive of such income from obligations issued by or on behalf of the state of Connecticut, any political subdivision thereof, or public instrumentality, state or local authority, district or similar public entity created under the laws of the state of Connecticut and exclusive of any such income with respect to which taxation by any state is prohibited by federal law;
(ii) Any exempt-interest dividends, as defined in Section 852(b)(5) of the Internal Revenue Code, exclusive of such exempt-interest dividends derived from obligations issued by or on behalf of the state of Connecticut, any political subdivision thereof, or public instrumentality, state or local authority, district or similar public entity created under the laws of the state of Connecticut and exclusive of such exempt-interest dividends derived from obligations, the income with respect to which taxation by any state is prohibited by federal law;
(iii) Any interest or dividend income on obligations or securities of any authority, commission or instrumentality of the United States that federal law exempts from federal income tax but does not exempt from state income taxes;
(iv) To the extent properly includable in determining the net gain or loss from the sale or other disposition of capital assets for federal income tax purposes, any loss from the sale or exchange of obligations issued by or on behalf of the state of Connecticut, any political subdivision thereof, or public instrumentality, state or local authority, district or similar public entity created under the laws of the state of Connecticut, in the income year such loss was recognized;
(v) To the extent deductible in determining federal taxable income prior to deductions relating to distributions to beneficiaries, any income taxes imposed by this state;
(vi) To the extent deductible in determining federal taxable income prior to deductions relating to distributions to beneficiaries, any interest on indebtedness incurred or continued to purchase or carry obligations or securities the interest on which is exempt from tax under this chapter;
(vii) Expenses paid or incurred during the taxable year for the production or collection of income which is exempt from tax under this chapter, or the management, conservation or maintenance of property held for the production of such income, and the amortizable bond premium for the taxable year on any bond the interest on which is exempt from taxation under this chapter, to the extent that such expenses and premiums are deductible in determining federal taxable income prior to deductions relating to distributions to beneficiaries;
(viii) To the extent deductible in determining federal taxable income prior to deductions relating to distributions to beneficiaries, the deduction allowable as qualified domestic production activities income, pursuant to Section 199 of the Internal Revenue Code; and
(ix) To the extent not includable in federal taxable income prior to deductions relating to distributions to beneficiaries, the total amount of a lump sum distribution for the taxable year.
(B) There shall be subtracted from the sum of such items:
(i) To the extent properly includable in gross income for federal income tax purposes, any income with respect to which taxation by any state is prohibited by federal law;
(ii) To the extent allowable under section 12-718 , exempt dividends paid by a regulated investment company;
(iii) With respect to any trust or estate that is a shareholder of an S corporation which is carrying on, or that has the right to carry on, business in this state, as said term is used in section 12-214 , the amount of such shareholder's pro rata share of such corporation's nonseparately computed items, as defined in Section 1366 of the Internal Revenue Code, that is subject to tax under chapter 208, in accordance with subsection (c) of section 12-217 multiplied by such corporation's apportionment fraction, if any, as determined in accordance with section 12-218 ;
(iv) To the extent properly includable in gross income for federal income tax purposes, any interest income from obligations issued by or on behalf of the state of Connecticut, any political subdivision thereof, or public instrumentality, state or local authority, district or similar public entity created under the laws of the state of Connecticut;
(v) To the extent properly includable in determining the net gain or loss from the sale or other disposition of capital assets for federal income tax purposes, any gain from the sale or exchange of obligations issued by or on behalf of the state of Connecticut, any political subdivision thereof, or public instrumentality, state or local authority, district or similar public entity created under the laws of the state of Connecticut, in the income year such gain was recognized;
(vi) Any interest on indebtedness incurred or continued to purchase or carry obligations or securities the interest on which is subject to tax under this chapter, but exempt from federal income tax, to the extent that such interest on indebtedness is not deductible in determining federal taxable income prior to deductions relating to distributions to beneficiaries;
(vii) Ordinary and necessary expenses paid or incurred during the taxable year for the production or collection of income that is subject to taxation under this chapter, but exempt from federal income tax, or the management, conservation or maintenance of property held for the production of such income, and the amortizable bond premium for the taxable year on any bond the interest on which is subject to tax under this chapter, but exempt from federal income tax, to the extent that such expenses and premiums are not deductible in determining federal taxable income prior to deductions relating to distributions to beneficiaries; and
(viii) The amount of any refund or credit for overpayment of income taxes imposed by this state, to the extent properly includable in gross income for federal income tax purposes for the taxable year and to the extent deductible in determining federal taxable income prior to deductions relating to distributions to beneficiaries for the preceding taxable year.
(11) “Estimated tax” means the amount which the individual estimates to be his income tax under this chapter for the taxable year less the amount which such individual estimates to be the sum of any credits allowable for tax withheld.
(12) “Required annual payment” means the lesser of (A) ninety per cent of the tax shown on the return for the taxable year, or, if no return is filed, ninety per cent of the tax for such year, or (B) if the preceding taxable year was a taxable year of twelve months and the individual filed a return for the preceding taxable year, one hundred per cent of the tax shown on the return of the individual for such preceding taxable year.
(13) “Regulated investment company” means a regulated investment company as defined in Section 851 of the Internal Revenue Code.
(14) “Exempt dividends” means any dividend or part thereof, other than a capital gain dividend, paid by a regulated investment company and designated by it as an exempt dividend, in accordance with section 12-718 , in a written notice mailed to its shareholders not later than sixty days after the close of its taxable year.
(15) “Taxpayer” means any person, trust or estate subject to the tax imposed under this chapter.
(16) “Internal Revenue Code” means the Internal Revenue Code of 1986, or any subsequent corresponding internal revenue code of the United States, as from time to time amended.
(17) “S corporation” means any corporation which is an S corporation for federal income tax purposes.
(18) “Person” means a person as defined in section 12-1 , but shall not include any corporation or association which is taxable as a corporation for the purposes of chapter 208, provided, for purposes of sections 12-735 , 12-736 and 12-737 , the term “person” shall include an individual, corporation or partnership and any officer or employee of any corporation, including a dissolved corporation, and a member or employee of any partnership who, as such officer, employee or member, is under a duty to perform the act in respect of which the violation occurs.
(19) “Adjusted gross income” means the adjusted gross income of a natural person with respect to any taxable year, as determined for federal income tax purposes and as properly reported on such person's federal income tax return.
(20) “Connecticut adjusted gross income” means adjusted gross income, with the following modifications:
(A) There shall be added thereto:
(i) To the extent not properly includable in gross income for federal income tax purposes, any interest income from obligations issued by or on behalf of any state, political subdivision thereof, or public instrumentality, state or local authority, district or similar public entity, exclusive of such income from obligations issued by or on behalf of the state of Connecticut, any political subdivision thereof, or public instrumentality, state or local authority, district or similar public entity created under the laws of the state of Connecticut and exclusive of any such income with respect to which taxation by any state is prohibited by federal law;
(ii) Any exempt-interest dividends, as defined in Section 852(b)(5) of the Internal Revenue Code, exclusive of such exempt-interest dividends derived from obligations issued by or on behalf of the state of Connecticut, any political subdivision thereof, or public instrumentality, state or local authority, district or similar public entity created under the laws of the state of Connecticut and exclusive of such exempt-interest dividends derived from obligations, the income with respect to which taxation by any state is prohibited by federal law;
(iii) Any interest or dividend income on obligations or securities of any authority, commission or instrumentality of the United States which federal law exempts from federal income tax but does not exempt from state income taxes;
(iv) To the extent included in gross income for federal income tax purposes for the taxable year, the total taxable amount of a lump sum distribution for the taxable year deductible from such gross income in calculating federal adjusted gross income;
(v) To the extent properly includable in determining the net gain or loss from the sale or other disposition of capital assets for federal income tax purposes, any loss from the sale or exchange of obligations issued by or on behalf of the state of Connecticut, any political subdivision thereof, or public instrumentality, state or local authority, district or similar public entity created under the laws of the state of Connecticut, in the income year such loss was recognized;
(vi) To the extent deductible in determining federal adjusted gross income, any income taxes imposed by this state;
(vii) To the extent deductible in determining federal adjusted gross income, any interest on indebtedness incurred or continued to purchase or carry obligations or securities the interest on which is exempt from tax under this chapter;
(viii) Expenses paid or incurred during the taxable year for the production or collection of income which is exempt from taxation under this chapter or the management, conservation or maintenance of property held for the production of such income, and the amortizable bond premium for the taxable year on any bond the interest on which is exempt from tax under this chapter to the extent that such expenses and premiums are deductible in determining federal adjusted gross income;
(ix) For property placed in service after September 27, 2017, any additional allowance for depreciation under subsection (k) of Section 168 of the Internal Revenue Code, to the extent deductible in determining federal adjusted gross income;
(x) To the extent deductible in determining federal adjusted gross income, the deduction allowable as qualified domestic production activities income, pursuant to Section 199 of the Internal Revenue Code;
(xi) To the extent not properly includable in gross income for federal income tax purposes for the taxable year, any income from the discharge of indebtedness, in taxable years ending after December 31, 2008, in connection with any reacquisition, after December 31, 2008, and before January 1, 2011, of an applicable debt instrument or instruments, as those terms are defined in Section 108 of the Internal Revenue Code, as amended by Section 1231 of the American Recovery and Reinvestment Act of 2009, the inclusion of which income in federal gross income for the taxable year is deferred, as provided by said Section 1231;
(xii) To the extent not properly includable in gross income for federal income tax purposes, an amount equal to (I) any distribution from a manufacturing reinvestment account not used in accordance with subdivision (3) of subsection (c) of section 32-9zz to the extent that a contribution to such account was subtracted from federal adjusted gross income pursuant to clause (xix) of subparagraph (B) of this subdivision in computing Connecticut adjusted gross income for the current or a preceding taxable year, and (II) any return of money from a manufacturing reinvestment account pursuant to subsection (d) of section 32-9zz to the extent that a contribution to such account was subtracted from federal adjusted gross income pursuant to clause (xix) of subparagraph (B) of this subdivision in computing Connecticut adjusted gross income for the current or a preceding taxable year;
(xiii) To the extent not properly includable in gross income for federal income tax purposes, an amount equal to any compensation required to be recognized under Section 457A of the Internal Revenue Code that is attributable to services performed within this state; and
(xiv) For taxable years commencing on or after January 1, 2018, eighty per cent of any deduction claimed for federal purposes under Section 179 of the Internal Revenue Code.
(B) There shall be subtracted therefrom:
(i) To the extent properly includable in gross income for federal income tax purposes, any income with respect to which taxation by any state is prohibited by federal law;
(ii) To the extent allowable under section 12-718 , exempt dividends paid by a regulated investment company;
(iii) To the extent properly includable in gross income for federal income tax purposes, the amount of any refund or credit for overpayment of income taxes imposed by this state, or any other state of the United States or a political subdivision thereof, or the District of Columbia;
(iv) To the extent properly includable in gross income for federal income tax purposes and not otherwise subtracted from federal adjusted gross income pursuant to clause (x) of this subparagraph in computing Connecticut adjusted gross income, any tier 1 railroad retirement benefits;
(v) To the extent any additional allowance for depreciation under Section 168(k) of the Internal Revenue Code for property placed in service after September 27, 2017, was added to federal adjusted gross income pursuant to subparagraph (A)(ix) of this subdivision in computing Connecticut adjusted gross income, twenty-five per cent of such additional allowance for depreciation in each of the four succeeding taxable years;
(vi) To the extent properly includable in gross income for federal income tax purposes, any interest income from obligations issued by or on behalf of the state of Connecticut, any political subdivision thereof, or public instrumentality, state or local authority, district or similar public entity created under the laws of the state of Connecticut;
(vii) To the extent properly includable in determining the net gain or loss from the sale or other disposition of capital assets for federal income tax purposes, any gain from the sale or exchange of obligations issued by or on behalf of the state of Connecticut, any political subdivision thereof, or public instrumentality, state or local authority, district or similar public entity created under the laws of the state of Connecticut, in the income year such gain was recognized;
(viii) Any interest on indebtedness incurred or continued to purchase or carry obligations or securities the interest on which is subject to tax under this chapter but exempt from federal income tax, to the extent that such interest on indebtedness is not deductible in determining federal adjusted gross income and is attributable to a trade or business carried on by such individual;
(ix) Ordinary and necessary expenses paid or incurred during the taxable year for the production or collection of income which is subject to taxation under this chapter but exempt from federal income tax, or the management, conservation or maintenance of property held for the production of such income, and the amortizable bond premium for the taxable year on any bond the interest on which is subject to tax under this chapter but exempt from federal income tax, to the extent that such expenses and premiums are not deductible in determining federal adjusted gross income and are attributable to a trade or business carried on by such individual;
(x) (I) For taxable years commencing prior to January 1, 2019, for a person who files a return under the federal income tax as an unmarried individual whose federal adjusted gross income for such taxable year is less than fifty thousand dollars, or as a married individual filing separately whose federal adjusted gross income for such taxable year is less than fifty thousand dollars, or for a husband and wife who file a return under the federal income tax as married individuals filing jointly whose federal adjusted gross income for such taxable year is less than sixty thousand dollars or a person who files a return under the federal income tax as a head of household whose federal adjusted gross income for such taxable year is less than sixty thousand dollars, an amount equal to the Social Security benefits includable for federal income tax purposes;
(II) For taxable years commencing prior to January 1, 2019, for a person who files a return under the federal income tax as an unmarried individual whose federal adjusted gross income for such taxable year is fifty thousand dollars or more, or as a married individual filing separately whose federal adjusted gross income for such taxable year is fifty thousand dollars or more, or for a husband and wife who file a return under the federal income tax as married individuals filing jointly whose federal adjusted gross income from such taxable year is sixty thousand dollars or more or for a person who files a return under the federal income tax as a head of household whose federal adjusted gross income for such taxable year is sixty thousand dollars or more, an amount equal to the difference between the amount of Social Security benefits includable for federal income tax purposes and the lesser of twenty-five per cent of the Social Security benefits received during the taxable year, or twenty-five per cent of the excess described in Section 86(b)(1) of the Internal Revenue Code;
(III) For the taxable year commencing January 1, 2019, and each taxable year thereafter, for a person who files a return under the federal income tax as an unmarried individual whose federal adjusted gross income for such taxable year is less than seventy-five thousand dollars, or as a married individual filing separately whose federal adjusted gross income for such taxable year is less than seventy-five thousand dollars, or for a husband and wife who file a return under the federal income tax as married individuals filing jointly whose federal adjusted gross income for such taxable year is less than one hundred thousand dollars or a person who files a return under the federal income tax as a head of household whose federal adjusted gross income for such taxable year is less than one hundred thousand dollars, an amount equal to the Social Security benefits includable for federal income tax purposes; and
(IV) For the taxable year commencing January 1, 2019, and each taxable year thereafter, for a person who files a return under the federal income tax as an unmarried individual whose federal adjusted gross income for such taxable year is seventy-five thousand dollars or more, or as a married individual filing separately whose federal adjusted gross income for such taxable year is seventy-five thousand dollars or more, or for a husband and wife who file a return under the federal income tax as married individuals filing jointly whose federal adjusted gross income from such taxable year is one hundred thousand dollars or more or for a person who files a return under the federal income tax as a head of household whose federal adjusted gross income for such taxable year is one hundred thousand dollars or more, an amount equal to the difference between the amount of Social Security benefits includable for federal income tax purposes and the lesser of twenty-five per cent of the Social Security benefits received during the taxable year, or twenty-five per cent of the excess described in Section 86(b)(1) of the Internal Revenue Code;
(xi) To the extent properly includable in gross income for federal income tax purposes, any amount rebated to a taxpayer pursuant to section 12-746 ;
(xii) To the extent properly includable in the gross income for federal income tax purposes of a designated beneficiary, any distribution to such beneficiary from any qualified state tuition program, as defined in Section 529(b) of the Internal Revenue Code, established and maintained by this state or any official, agency or instrumentality of the state;
(xiii) To the extent allowable under section 12-701a , contributions to accounts established pursuant to any qualified state tuition program, as defined in Section 529(b) of the Internal Revenue Code, established and maintained by this state or any official, agency or instrumentality of the state;
(xiv) To the extent properly includable in gross income for federal income tax purposes, the amount of any Holocaust victims' settlement payment received in the taxable year by a Holocaust victim;
(xv) To the extent properly includable in the gross income for federal income tax purposes of a designated beneficiary, as defined in section 3-123aa , interest, dividends or capital gains earned on contributions to accounts established for the designated beneficiary pursuant to the Connecticut Homecare Option Program for the Elderly established by sections 3-123aa to 3-123ff , inclusive;
(xvi) To the extent properly includable in gross income for federal income tax purposes, any income received from the United States government as retirement pay for a retired member of (I) the Armed Forces of the United States, as defined in Section 101 of Title 10 of the United States Code, or (II) the National Guard, as defined in Section 101 of Title 10 of the United States Code;
(xvii) To the extent properly includable in gross income for federal income tax purposes for the taxable year, any income from the discharge of indebtedness in connection with any reacquisition, after December 31, 2008, and before January 1, 2011, of an applicable debt instrument or instruments, as those terms are defined in Section 108 of the Internal Revenue Code, as amended by Section 1231 of the American Recovery and Reinvestment Act of 2009, to the extent any such income was added to federal adjusted gross income pursuant to subparagraph (A)(xi) of this subdivision in computing Connecticut adjusted gross income for a preceding taxable year;
(xviii) To the extent not deductible in determining federal adjusted gross income, the amount of any contribution to a manufacturing reinvestment account established pursuant to section 32-9zz in the taxable year that such contribution is made;
(xix) To the extent properly includable in gross income for federal income tax purposes, (I) for the taxable year commencing January 1, 2015, ten per cent of the income received from the state teachers' retirement system, (II) for the taxable years commencing January 1, 2016, to January 1, 2020, inclusive, twenty-five per cent of the income received from the state teachers' retirement system, and (III) for the taxable year commencing January 1, 2021, and each taxable year thereafter, fifty per cent of the income received from the state teachers' retirement system or, for a taxpayer whose federal adjusted gross income does not exceed the applicable threshold under clause (xx) of this subparagraph, the percentage pursuant to said clause of the income received from the state teachers' retirement system, whichever deduction is greater;
(xx) To the extent properly includable in gross income for federal income tax purposes, except for retirement benefits under clause (iv) of this subparagraph and retirement pay under clause (xvi) of this subparagraph, for a person who files a return under the federal income tax as an unmarried individual whose federal adjusted gross income for such taxable year is less than seventy-five thousand dollars, or as a married individual filing separately whose federal adjusted gross income for such taxable year is less than seventy-five thousand dollars, or as a head of household whose federal adjusted gross income for such taxable year is less than seventy-five thousand dollars, or for a husband and wife who file a return under the federal income tax as married individuals filing jointly whose federal adjusted gross income for such taxable year is less than one hundred thousand dollars, (I) for the taxable year commencing January 1, 2019, fourteen per cent of any pension or annuity income, (II) for the taxable year commencing January 1, 2020, twenty-eight per cent of any pension or annuity income, (III) for the taxable year commencing January 1, 2021, forty-two per cent of any pension or annuity income, and (IV) for the taxable years commencing January 1, 2022, and January 1, 2023, one hundred per cent of any pension or annuity income;
(xxi) To the extent properly includable in gross income for federal income tax purposes, except for retirement benefits under clause (iv) of this subparagraph and retirement pay under clause (xvi) of this subparagraph, any pension or annuity income for the taxable year commencing on or after January 1, 2024, and each taxable year thereafter, in accordance with the following schedule, for a person who files a return under the federal income tax as an unmarried individual whose federal adjusted gross income for such taxable year is less than one hundred thousand dollars, or as a married individual filing separately whose federal adjusted gross income for such taxable year is less than one hundred thousand dollars, or as a head of household whose federal adjusted gross income for such taxable year is less than one hundred thousand dollars: