§ 163. Interest

(a) General rule
There shall be allowed as a deduction all interest paid or accrued within the taxable year on indebtedness.
(b) Installment purchases where interest charge is not separately stated
(1) General rule
If personal property or educational services are purchased under a contract—
(A) which provides that payment of part or all of the purchase price is to be made in installments, and
(B) in which carrying charges are separately stated but the interest charge cannot be ascertained,
then the payments made during the taxable year under the contract shall be treated for purposes of this section as if they included interest equal to 6 percent of the average unpaid balance under the contract during the taxable year. For purposes of the preceding sentence, the average unpaid balance is the sum of the unpaid balance outstanding on the first day of each month beginning during the taxable year, divided by 12. For purposes of this paragraph, the term “educational services” means any service (including lodging) which is purchased from an educational organization described in section 170 (b)(1)(A)(ii) and which is provided for a student of such organization.
(2) Limitation
In the case of any contract to which paragraph (1) applies, the amount treated as interest for any taxable year shall not exceed the aggregate carrying charges which are properly attributable to such taxable year.
(c) Redeemable ground rents
For purposes of this subtitle, any annual or periodic rental under a redeemable ground rent (excluding amounts in redemption thereof) shall be treated as interest on an indebtedness secured by a mortgage.
(d) Limitation on investment interest
(1) In general
In the case of a taxpayer other than a corporation, the amount allowed as a deduction under this chapter for investment interest for any taxable year shall not exceed the net investment income of the taxpayer for the taxable year.
(2) Carryforward of disallowed interest
The amount not allowed as a deduction for any taxable year by reason of paragraph (1) shall be treated as investment interest paid or accrued by the taxpayer in the succeeding taxable year.
(3) Investment interest
For purposes of this subsection—
(A) In general
The term “investment interest” means any interest allowable as a deduction under this chapter (determined without regard to paragraph (1)) which is paid or accrued on indebtedness properly allocable to property held for investment.
(B) Exceptions
The term “investment interest” shall not include—
(i) any qualified residence interest (as defined in subsection (h)(3)), or
(ii) any interest which is taken into account under section 469 in computing income or loss from a passive activity of the taxpayer.
(C) Personal property used in short sale
For purposes of this paragraph, the term “interest” includes any amount allowable as a deduction in connection with personal property used in a short sale.
(4) Net investment income
For purposes of this subsection—
(A) In general
The term “net investment income” means the excess of—
(i) investment income, over
(ii) investment expenses.
(B) Investment income
The term “investment income” means the sum of—
(i) gross income from property held for investment (other than any gain taken into account under clause (ii)(I)),
(ii) the excess (if any) of—
(I) the net gain attributable to the disposition of property held for investment, over
(II) the net capital gain determined by only taking into account gains and losses from dispositions of property held for investment, plus
(iii) so much of the net capital gain referred to in clause (ii)(II) (or, if lesser, the net gain referred to in clause (ii)(I)) as the taxpayer elects to take into account under this clause.
Such term shall include qualified dividend income (as defined in section 1 (h)(11)(B)) only to the extent the taxpayer elects to treat such income as investment income for purposes of this subsection.
(C) Investment expenses
The term “investment expenses” means the deductions allowed under this chapter (other than for interest) which are directly connected with the production of investment income.
(D) Income and expenses from passive activities
Investment income and investment expenses shall not include any income or expenses taken into account under section 469 in computing income or loss from a passive activity.
(E) Reduction in investment income during phase-in of passive loss rules
Investment income of the taxpayer for any taxable year shall be reduced by the amount of the passive activity loss to which section 469 (a) does not apply for such taxable year by reason of section 469 (m). The preceding sentence shall not apply to any portion of such passive activity loss which is attributable to a rental real estate activity with respect to which the taxpayer actively participates (within the meaning of section 469 (i)(6)) during such taxable year.
(5) Property held for investment
For purposes of this subsection—
(A) In general
The term “property held for investment” shall include—
(i) any property which produces income of a type described in section 469 (e)(1), and
(ii) any interest held by a taxpayer in an activity involving the conduct of a trade or business—
(I) which is not a passive activity, and
(II) with respect to which the taxpayer does not materially participate.
(B) Investment expenses
In the case of property described in subparagraph (A)(i), expenses shall be allocated to such property in the same manner as under section 469.
(C) Terms
For purposes of this paragraph, the terms “activity”, “passive activity”, and “materially participate” have the meanings given such terms by section 469.
(6) Phase-in of disallowance
In the case of any taxable year beginning in calendar years 1987 through 1990—
(A) In general
The amount of interest paid or accrued during any such taxable year which is disallowed under this subsection shall not exceed the sum of—
(i) the amount which would be disallowed under this subsection if—
(I) paragraph (1) were applied by substituting “the sum of the ceiling amount and the net investment income” for “the net investment income”, and
(II) paragraphs (4)(E) and (5)(A)(ii) did not apply, and
(ii) the applicable percentage of the excess of—
(I) the amount which (without regard to this paragraph) is not allowable as a deduction under this subsection for the taxable year, over
(II) the amount described in clause (i).
The preceding sentence shall not apply to any interest treated as paid or accrued during the taxable year under paragraph (2).
(B) Applicable percentage
For purposes of this paragraph, the applicable percentage shall be determined in accordance with the following table:

 
In the case of taxable years beginning in: The applicable percentage is:
1987 35  
1988 60  
1989 80  
1990 90.

(C) Ceiling amount
For purposes of this paragraph, the term “ceiling amount” means—
(i) $10,000 in the case of a taxpayer not described in clause (ii) or (iii),
(ii) $5,000 in the case of a married individual filing a separate return, and
(iii) zero in the case of a trust.
(e) Original issue discount
(1) In general
In the case of any debt instrument issued after July 1, 1982, the portion of the original issue discount with respect to such debt instrument which is allowable as a deduction to the issuer for any taxable year shall be equal to the aggregate daily portions of the original issue discount for days during such taxable year.
(2) Definitions and special rules
For purposes of this subsection—
(A) Debt instrument
The term “debt instrument” has the meaning given such term by section 1275 (a)(1).
(B) Daily portions
The daily portion of the original issue discount for any day shall be determined under section 1272 (a) (without regard to paragraph (7) thereof and without regard to section 1273 (a)(3)).
(C) Short-term obligations
In the case of an obligor of a short-term obligation (as defined in section 1283 (a)(1)(A)) who uses the cash receipts and disbursements method of accounting, the original issue discount (and any other interest payable) on such obligation shall be deductible only when paid.
(3) Special rule for original issue discount on obligation held by related foreign person
(A) In general
If any debt instrument having original issue discount is held by a related foreign person, any portion of such original issue discount shall not be allowable as a deduction to the issuer until paid. The preceding sentence shall not apply to the extent that the original issue discount is effectively connected with the conduct by such foreign related person of a trade or business within the United States unless such original issue discount is exempt from taxation (or is subject to a reduced rate of tax) pursuant to a treaty obligation of the United States.
(B) Special rule for certain foreign entities
(i) In general In the case of any debt instrument having original issue discount which is held by a related foreign person which is a controlled foreign corporation (as defined in section 957) or a passive foreign investment company (as defined in section 1297), a deduction shall be allowable to the issuer with respect to such original issue discount for any taxable year before the taxable year in which paid only to the extent such original issue discount is includible (determined without regard to properly allocable deductions and qualified deficits under section 952 (c)(1)(B)) during such prior taxable year in the gross income of a United States person who owns (within the meaning of section 958 (a)) stock in such corporation.
(ii) Secretarial authority The Secretary may by regulation exempt transactions from the application of clause (i), including any transaction which is entered into by a payor in the ordinary course of a trade or business in which the payor is predominantly engaged.
(C) Related foreign person
For purposes of subparagraph (A), the term “related foreign person” means any person—
(i) who is not a United States person, and
(ii) who is related (within the meaning of section 267 (b)) to the issuer.
(4) Exceptions
This subsection shall not apply to any debt instrument described in—
(A) subparagraph (D) of section 1272 (a)(2) (relating to obligations issued by natural persons before March 2, 1984), and
(B) subparagraph (E) of section 1272 (a)(2) (relating to loans between natural persons).
(5) Special rules for original issue discount on certain high yield obligations
(A) In general
In the case of an applicable high yield discount obligation issued by a corporation—
(i) no deduction shall be allowed under this chapter for the disqualified portion of the original issue discount on such obligation, and
(ii) the remainder of such original issue discount shall not be allowable as a deduction until paid.
For purposes of this paragraph, rules similar to the rules of subsection (i)(3)(B) shall apply in determining the amount of the original issue discount and when the original issue discount is paid.
(B) Disqualified portion treated as stock distribution for purposes of dividend received deduction
(i) In general Solely for purposes of sections 243, 245, 246, and 246A, the dividend equivalent portion of any amount includible in gross income of a corporation under section 1272 (a) in respect of an applicable high yield discount obligation shall be treated as a dividend received by such corporation from the corporation issuing such obligation.
(ii) Dividend equivalent portion For purposes of clause (i), the dividend equivalent portion of any amount includible in gross income under section 1272 (a) in respect of an applicable high yield discount obligation is the portion of the amount so includible—
(I) which is attributable to the disqualified portion of the original issue discount on such obligation, and
(II) which would have been treated as a dividend if it had been a distribution made by the issuing corporation with respect to stock in such corporation.
(C) Disqualified portion
(i) In general For purposes of this paragraph, the disqualified portion of the original issue discount on any applicable high yield discount obligation is the lesser of—
(I) the amount of such original issue discount, or
(II) the portion of the total return on such obligation which bears the same ratio to such total return as the disqualified yield on such obligation bears to the yield to maturity on such obligation.
(ii) Definitions For purposes of clause (i), the term “disqualified yield” means the excess of the yield to maturity on the obligation over the sum referred to [1] subsection (i)(1)(B) plus 1 percentage point, and the term “total return” is the amount which would have been the original issue discount on the obligation if interest described in the parenthetical in section 1273 (a)(2) were included in the stated redemption price at maturity.
(D) Exception for S corporations
This paragraph shall not apply to any obligation issued by any corporation for any period for which such corporation is an S corporation.
(E) Effect on earnings and profits
This paragraph shall not apply for purposes of determining earnings and profits; except that, for purposes of determining the dividend equivalent portion of any amount includible in gross income under section 1272 (a) in respect of an applicable high yield discount obligation, no reduction shall be made for any amount attributable to the disqualified portion of any original issue discount on such obligation.
(F) Suspension of application of paragraph
(i) Temporary suspension This paragraph shall not apply to any applicable high yield discount obligation issued during the period beginning on September 1, 2008, and ending on December 31, 2009, in exchange (including an exchange resulting from a modification of the debt instrument) for an obligation which is not an applicable high yield discount obligation and the issuer (or obligor) of which is the same as the issuer (or obligor) of such applicable high yield discount obligation. The preceding sentence shall not apply to any obligation the interest on which is interest described in section 871 (h)(4) (without regard to subparagraph (D) thereof) or to any obligation issued to a related person (within the meaning of section 108 (e)(4)).
(ii) Successive application Any obligation to which clause (i) applies shall not be treated as an applicable high yield discount obligation for purposes of applying this subparagraph to any other obligation issued in exchange for such obligation.
(iii) Secretarial authority to suspend application The Secretary may apply this paragraph with respect to debt instruments issued in periods following the period described in clause (i) if the Secretary determines that such application is appropriate in light of distressed conditions in the debt capital markets.
(G) Cross reference
For definition of applicable high yield discount obligation, see subsection (i).
(6) Cross references
For provision relating to deduction of original issue discount on tax-exempt obligation, see section 1288.
For special rules in the case of the borrower under certain loans for personal use, see section 1275 (b).
(f) Denial of deduction for interest on certain obligations not in registered form
(1) In general
Nothing in subsection (a) or in any other provision of law shall be construed to provide a deduction for interest on any registration-required obligation unless such obligation is in registered form.
(2) Registration-required obligation
For purposes of this section—
(A) In general
The term “registration-required obligation” means any obligation (including any obligation issued by a governmental entity) other than an obligation which—
(i) is issued by a natural person,
(ii) is not of a type offered to the public,
(iii) has a maturity (at issue) of not more than 1 year, or
(iv) is described in subparagraph (B).
(B) Certain obligations not included
An obligation is described in this subparagraph if—
(i) there are arrangements reasonably designed to ensure that such obligation will be sold (or resold in connection with the original issue) only to a person who is not a United States person, and
(ii) in the case of an obligation not in registered form—
(I) interest on such obligation is payable only outside the United States and its possessions, and
(II) on the face of such obligation there is a statement that any United States person who holds such obligation will be subject to limitations under the United States income tax laws.
(C) Authority to include other obligations
Clauses (ii) and (iii) of subparagraph (A), and subparagraph (B), shall not apply to any obligation if—
(i) in the case of—
(I) subparagraph (A), such obligation is of a type which the Secretary has determined by regulations to be used frequently in avoiding Federal taxes, or
(II) subparagraph (B), such obligation is of a type specified by the Secretary in regulations, and
(ii) such obligation is issued after the date on which the regulations referred to in clause (i) take effect.
(3) Book entries permitted, etc.
For purposes of this subsection, rules similar to the rules of section 149 (a)(3) shall apply.
(g) Reduction of deduction where section 25 credit taken
The amount of the deduction under this section for interest paid or accrued during any taxable year on indebtedness with respect to which a mortgage credit certificate has been issued under section 25 shall be reduced by the amount of the credit allowable with respect to such interest under section 25 (determined without regard to section 26).
(h) Disallowance of deduction for personal interest
(1) In general
In the case of a taxpayer other than a corporation, no deduction shall be allowed under this chapter for personal interest paid or accrued during the taxable year.
(2) Personal interest
For purposes of this subsection, the term “personal interest” means any interest allowable as a deduction under this chapter other than—
(A) interest paid or accrued on indebtedness properly allocable to a trade or business (other than the trade or business of performing services as an employee),
(B) any investment interest (within the meaning of subsection (d)),
(C) any interest which is taken into account under section 469 in computing income or loss from a passive activity of the taxpayer,
(D) any qualified residence interest (within the meaning of paragraph (3)),
(E) any interest payable under section 6601 on any unpaid portion of the tax imposed by section 2001 for the period during which an extension of time for payment of such tax is in effect under section 6163, and
(F) any interest allowable as a deduction under section 221 (relating to interest on educational loans).
(3) Qualified residence interest
For purposes of this subsection—
(A) In general
The term “qualified residence interest” means any interest which is paid or accrued during the taxable year on—
(i) acquisition indebtedness with respect to any qualified residence of the taxpayer, or
(ii) home equity indebtedness with respect to any qualified residence of the taxpayer.
For purposes of the preceding sentence, the determination of whether any property is a qualified residence of the taxpayer shall be made as of the time the interest is accrued.
(B) Acquisition indebtedness
(i) In general The term “acquisition indebtedness” means any indebtedness which—
(I) is incurred in acquiring, constructing, or substantially improving any qualified residence of the taxpayer, and
(II) is secured by such residence.
 Such term also includes any indebtedness secured by such residence resulting from the refinancing of indebtedness meeting the requirements of the preceding sentence (or this sentence); but only to the extent the amount of the indebtedness resulting from such refinancing does not exceed the amount of the refinanced indebtedness.
(ii) $1,000,000 limitation The aggregate amount treated as acquisition indebtedness for any period shall not exceed $1,000,000 ($500,000 in the case of a married individual filing a separate return).
(C) Home equity indebtedness
(i) In general The term “home equity indebtedness” means any indebtedness (other than acquisition indebtedness) secured by a qualified residence to the extent the aggregate amount of such indebtedness does not exceed—
(I) the fair market value of such qualified residence, reduced by
(II) the amount of acquisition indebtedness with respect to such residence.
(ii) Limitation The aggregate amount treated as home equity indebtedness for any period shall not exceed $100,000 ($50,000 in the case of a separate return by a married individual).
(D) Treatment of indebtedness incurred on or before October 13, 1987
(i) In general In the case of any pre-October 13, 1987, indebtedness—
(I) such indebtedness shall be treated as acquisition indebtedness, and
(II) the limitation of subparagraph (B)(ii) shall not apply.
(ii) Reduction in $1,000,000 limitation The limitation of subparagraph (B)(ii) shall be reduced (but not below zero) by the aggregate amount of outstanding pre-October 13, 1987, indebtedness.
(iii) Pre-October 13, 1987, indebtedness The term “pre-October 13, 1987, indebtedness” means—
(I) any indebtedness which was incurred on or before October 13, 1987, and which was secured by a qualified residence on October 13, 1987, and at all times thereafter before the interest is paid or accrued, or
(II) any indebtedness which is secured by the qualified residence and was incurred after October 13, 1987, to refinance indebtedness described in subclause (I) (or refinanced indebtedness meeting the requirements of this subclause) to the extent (immediately after the refinancing) the principal amount of the indebtedness resulting from the refinancing does not exceed the principal amount of the refinanced indebtedness (immediately before the refinancing).
(iv) Limitation on period of refinancing Subclause (II) of clause (iii) shall not apply to any indebtedness after—
(I) the expiration of the term of the indebtedness described in clause (iii)(I), or
(II) if the principal of the indebtedness described in clause (iii)(I) is not amortized over its term, the expiration of the term of the 1st refinancing of such indebtedness (or if earlier, the date which is 30 years after the date of such 1st refinancing).
(E) Mortgage insurance premiums treated as interest
(i) In general Premiums paid or accrued for qualified mortgage insurance by a taxpayer during the taxable year in connection with acquisition indebtedness with respect to a qualified residence of the taxpayer shall be treated for purposes of this section as interest which is qualified residence interest.
(ii) Phaseout The amount otherwise treated as interest under clause (i) shall be reduced (but not below zero) by 10 percent of such amount for each $1,000 ($500 in the case of a married individual filing a separate return) (or fraction thereof) that the taxpayer’s adjusted gross income for the taxable year exceeds $100,000 ($50,000 in the case of a married individual filing a separate return).
(iii) Limitation Clause (i) shall not apply with respect to any mortgage insurance contracts issued before January 1, 2007.
(iv) Termination Clause (i) shall not apply to amounts—
(I) paid or accrued after December 31, 2011, or
(II) properly allocable to any period after such date.
(4) Other definitions and special rules
For purposes of this subsection—
(A) Qualified residence
(i) In general The term “qualified residence” means—
(I) the principal residence (within the meaning of section 121) of the taxpayer, and
(II) 1 other residence of the taxpayer which is selected by the taxpayer for purposes of this subsection for the taxable year and which is used by the taxpayer as a residence (within the meaning of section 280A (d)(1)).
(ii) Married individuals filing separate returns If a married couple does not file a joint return for the taxable year—
(I) such couple shall be treated as 1 taxpayer for purposes of clause (i), and
(II) each individual shall be entitled to take into account 1 residence unless both individuals consent in writing to 1 individual taking into account the principal residence and 1 other residence.
(iii) Residence not rented For purposes of clause (i)(II), notwithstanding section 280A (d)(1), if the taxpayer does not rent a dwelling unit at any time during a taxable year, such unit may be treated as a residence for such taxable year.
(B) Special rule for cooperative housing corporations
Any indebtedness secured by stock held by the taxpayer as a tenant-stockholder (as defined in section 216) in a cooperative housing corporation (as so defined) shall be treated as secured by the house or apartment which the taxpayer is entitled to occupy as such a tenant-stockholder. If stock described in the preceding sentence may not be used to secure indebtedness, indebtedness shall be treated as so secured if the taxpayer establishes to the satisfaction of the Secretary that such indebtedness was incurred to acquire such stock.
(C) Unenforceable security interests
Indebtedness shall not fail to be treated as secured by any property solely because, under any applicable State or local homestead or other debtor protection law in effect on August 16, 1986, the security interest is ineffective or the enforceability of the security interest is restricted.
(D) Special rules for estates and trusts
For purposes of determining whether any interest paid or accrued by an estate or trust is qualified residence interest, any residence held by such estate or trust shall be treated as a qualified residence of such estate or trust if such estate or trust establishes that such residence is a qualified residence of a beneficiary who has a present interest in such estate or trust or an interest in the residuary of such estate or trust.
(E) Qualified mortgage insurance
The term “qualified mortgage insurance” means—
(i) mortgage insurance provided by the Veterans Administration, the Federal Housing Administration, or the Rural Housing Administration, and
(ii) private mortgage insurance (as defined by section 2 of the Homeowners Protection Act of 1998 (12 U.S.C. 4901), as in effect on the date of the enactment of this subparagraph).
(F) Special rules for prepaid qualified mortgage insurance
Any amount paid by the taxpayer for qualified mortgage insurance that is properly allocable to any mortgage the payment of which extends to periods that are after the close of the taxable year in which such amount is paid shall be chargeable to capital account and shall be treated as paid in such periods to which so allocated. No deduction shall be allowed for the unamortized balance of such account if such mortgage is satisfied before the end of its term. The preceding sentences shall not apply to amounts paid for qualified mortgage insurance provided by the Veterans Administration or the Rural Housing Administration.
(5) Phase-in of limitation
In the case of any taxable year beginning in calendar years 1987 through 1990, the amount of interest with respect to which a deduction is disallowed under this subsection shall be equal to the applicable percentage (within the meaning of subsection (d)(6)(B)) of the amount which (but for this paragraph) would have been so disallowed.
(i) Applicable high yield discount obligation
(1) In general
For purposes of this section, the term “applicable high yield discount obligation” means any debt instrument if—
(A) the maturity date of such instrument is more than 5 years from the date of issue,
(B) the yield to maturity on such instrument equals or exceeds the sum of—
(i) the applicable Federal rate in effect under section 1274 (d) for the calendar month in which the obligation is issued, plus
(ii) 5 percentage points, and
(C) such instrument has significant original issue discount.
For purposes of subparagraph (B)(i), the Secretary may by regulation (i) permit a rate to be used with respect to any debt instrument which is higher than the applicable Federal rate if the taxpayer establishes to the satisfaction of the Secretary that such higher rate is based on the same principles as the applicable Federal rate and is appropriate for the term of the instrument, or (ii) permit, on a temporary basis, a rate to be used with respect to any debt instrument which is higher than the applicable Federal rate if the Secretary determines that such rate is appropriate in light of distressed conditions in the debt capital markets.
(2) Significant original issue discount
For purposes of paragraph (1)(C), a debt instrument shall be treated as having significant original issue discount if—
(A) the aggregate amount which would be includible in gross income with respect to such instrument for periods before the close of any accrual period (as defined in section 1272 (a)(5)) ending after the date 5 years after the date of issue, exceeds—
(B) the sum of—
(i) the aggregate amount of interest to be paid under the instrument before the close of such accrual period, and
(ii) the product of the issue price of such instrument (as defined in sections 1273 (b) and 1274 (a)) and its yield to maturity.
(3) Special rules
For purposes of determining whether a debt instrument is an applicable high yield discount obligation—
(A) any payment under the instrument shall be assumed to be made on the last day permitted under the instrument, and
(B) any payment to be made in the form of another obligation of the issuer (or a related person within the meaning of section 453 (f)(1)) shall be assumed to be made when such obligation is required to be paid in cash or in property other than such obligation.
Except for purposes of paragraph (1)(B), any reference to an obligation in subparagraph (B) of this paragraph shall be treated as including a reference to stock.
(4) Debt instrument
For purposes of this subsection, the term “debt instrument” means any instrument which is a debt instrument as defined in section 1275 (a).
(5) Regulations
The Secretary shall prescribe such regulations as may be appropriate to carry out the purposes of this subsection and subsection (e)(5), including—
(A) regulations providing for modifications to the provisions of this subsection and subsection (e)(5) in the case of varying rates of interest, put or call options, indefinite maturities, contingent payments, assumptions of debt instruments, conversion rights, or other circumstances where such modifications are appropriate to carry out the purposes of this subsection and subsection (e)(5), and
(B) regulations to prevent avoidance of the purposes of this subsection and subsection (e)(5) through the use of issuers other than C corporations, agreements to borrow amounts due under the debt instrument, or other arrangements.
(j) Limitation on deduction for interest on certain indebtedness
(1) Limitation
(A) In general
If this subsection applies to any corporation for any taxable year, no deduction shall be allowed under this chapter for disqualified interest paid or accrued by such corporation during such taxable year. The amount disallowed under the preceding sentence shall not exceed the corporation’s excess interest expense for the taxable year.