1990—Subsecs. (i), (j). Pub. L. 101–508 redesignated subsec. (j) as (i) and struck out former subsec. (i) which related to deduction of certain pre-1970 exploration expenditures.

1988—Subsec. (j). Pub. L. 100–647 substituted “section 59(e)” for “section 58(i)”.

1986—Subsec. (d)(5). Pub. L. 99–514, § 413(b), added par. (5).

Subsec. (h). Pub. L. 99–514, § 411(b)(2)(B), amended subsec. (h) generally, substituting provisions relating to special rules for foreign exploration for provisions relating to limitations.

1982—Subsec. (h)(3)(B). Pub. L. 97–248, § 224(c)(8), inserted “338,” after “334(b),”.

Subsec. (j). Pub. L. 97–248, § 201(d)(9)(D), formerly § 201(c)(9)(D), added subsec. (j).

1976—Subsec. (a)(2)(A). Pub. L. 94–455, § 1906(b)(13)(A), struck out “or his delegate” after “Secretary”.

Subsec. (a)(2)(B). Pub. L. 94–455, §§ 1901(a)(89), 1906(b)(13)(A), substituted “may not be revoked unless” for “may not be revoked after the last day of the third month following the month in which the final regulations issued under the authority of this subsection are published in the Federal Register, unless”, and struck out “or his delegate” after “Secretary”.

Subsec. (b)(2)(A). Pub. L. 94–455, § 1906(b)(13)(A), struck out “or his delegate” after “Secretary”.

Subsec. (d)(1). Pub. L. 94–455, § 1901(b)(3)(K), substituted “ordinary income” for “gain from the sale or exchange of property which is neither a capital asset nor property described in section 1231”.

Subsecs. (d)(2), (e)(2), (g)(2). Pub. L. 94–455, § 1906(b)(13)(A), struck out “or his delegate” after “Secretary”.

Subsec. (h)(1). Pub. L. 94–455, § 1901(b)(21)(C), substituted “and subsection (a) of section 615 (as in effect before the enactment of the Tax Reform Act of 1976)” for “and section 615(a) and the amounts which are or have been treated as deferred expenses under section 615(b)”.

Subsec. (h)(3). Pub. L. 94–455, § 1901(b)(21)(D), struck out “and all amounts treated as deferred expenses which were paid or incurred” after “amounts deducted” in introductory provisions, redesignated subpar. (C) as (B), and in subpar. (B) as so redesignated, substituted “374(b)(1)” for “373(b)(1)”. Former subpar. (B), which related to the application of par. (2)(B) where the taxpayer would be entitled under section 381(c)(10) to deduct expenses deferred under section 615(b) had the distributor or transferor corporation elected to defer such expenses, was struck out.

Subsec. (i). Pub. L. 94–455, § 1901(b)(21)(E), added subsec. (i).

1969—Pub. L. 91–172, § 504(b)(1), substituted “Deduction and recapture of certain mining exploration expenditures” for “Additional exploration expenditures in the case of domestic mining” in heading.

Subsec. (a)(1). Pub. L. 91–172, § 504(b)(2), struck out reference to United States, the Outer Continental Shelf and the Outer Continental Shelf Lands Act from general rule dealing with allowance of deductions for expenditures in ascertaining the existence, location, extent, or quality of any deposit of ore or other mineral.

Subsec. (h). Pub. L. 91–172, § 504(b)(3), substituted provisions imposing limitations on the operation of this section for provision making cross reference to subsecs. (f) and (g) of section 615.

Amendment by Pub. L. 100–647 effective, except as otherwise provided, as if included in the provision of the Tax Reform Act of 1986, Pub. L. 99–514, to which such amendment relates, see section 1019(a) of Pub. L. 100–647, set out as a note under section 1 of this title.

Amendment by section 411(b)(2)(B) of Pub. L. 99–514 applicable to costs paid or incurred after Dec. 31, 1986, in taxable years ending after such date, with transition rule, see section 411(c) of Pub. L. 99–514 set out as a note under section 263 of this title.

Amendment by section 413(b) of Pub. L. 99–514 applicable to any disposition of property placed in service by taxpayer after Dec. 31, 1986, but inapplicable if such property was acquired pursuant to written contract entered into before Sept. 26, 1985, and binding at all times thereafter, see section 413(c) of Pub. L. 99–514, set out as a note under section 1254 of this title.

Amendment by section 201(d)(9)(D) of Pub. L. 97–248 applicable to taxable years beginning after Dec. 31, 1982, see section 201(e)(1) of Pub. L. 97–248, set out as a note under section 5 of this title.

Amendment by section 224(c)(8) of Pub. L. 97–248 applicable to any target corporation with respect to which the acquisition date occurs after Aug. 31, 1982, with special rules for certain acquisitions before Sept. 1, 1982, and certain acquisitions of financial institutions in which there was a binding contract on July 22, 1982, to acquire control, see section 224(d) of Pub. L. 97–248, set out as an Effective Date note under section 338 of this title.

Amendment by section 1901(a)(89), (b)(3)(K), (21)(C)–(E) of Pub. L. 94–455 effective for taxable years beginning after Dec. 31, 1976, see section 1901(d) of Pub. L. 94–455, set out as a note under section 2 of this title.

Amendment by Pub. L. 91–172 applicable with respect to exploration expenditures paid or incurred after Dec. 31, 1969, and for purposes of this section, elections under section 615(e) of this title, effective with respect to exploration expenditures paid or incurred before Jan. 1, 1970, to be treated as an election under subsec. (a) of this section with respect to exploration expenditures paid or incurred after Dec. 31, 1969, see section 504(d) of Pub. L. 91–172, set out as a note under section 243 of this title.

Pub. L. 89–570, § 3, Sept. 12, 1966, 80 Stat. 764, provided that: “The amendments made by this Act [enacting this section and amending sections 170, 301, 312, 341, 453, 615, 703, and 751 of this title] shall apply to taxable years ending after the date of the enactment of this Act [Sept. 12, 1966] but only in respect of expenditures paid or incurred after such date.”

For provisions that nothing in amendment by Pub. L. 101–508 be construed to affect treatment of certain transactions occurring, property acquired, or items of income, loss, deduction, or credit taken into account prior to Nov. 5, 1990, for purposes of determining liability for tax for periods ending after Nov. 5, 1990, see section 11821(b) of Pub. L. 101–508, set out as a note under section 45K of this title.