26 U.S.C. § 316: Dividend defined

out of its earnings and profits accumulated after February 28, 1913 , or out of its earnings and profits of the taxable year (computed as of the close of the taxable year without diminution by reason of any distributions made during the taxable year), without regard to the amount of the earnings and profits at the time the distribution was made. The definition in subsection (a) shall not apply to the term “dividend” as used in subchapter L in any case where the reference is to dividends of insurance companies paid to policyholders as such. under the law applicable to the taxable year in which the distribution is made, is a personal holding company (as defined in section 542), or for the taxable year in respect of which the distribution is made under section 563(b) (relating to dividends paid after the close of the taxable year), or section 547 (relating to deficiency dividends), or the corresponding provisions of prior law, is a personal holding company under the law applicable to such taxable year, only to the extent of the amounts distributed to distributees other than corporate shareholders, and only to the extent that the corporation designates such amounts as a dividend distribution and duly notifies such distributees of such designation, under regulations prescribed by the Secretary, but not in excess of the sum of such distributees’ allocable share of the undistributed personal holding company income for such year, computed without regard to this subparagraph or section 562(b). The term “dividend” also means any distribution of property (whether or not a dividend as defined in subsection (a)) which constitutes a “deficiency dividend” as defined in section 860(f). In the case of a regulated investment company that has a taxable year other than a calendar year, if the distributions by the company with respect to any class of stock of such company for the taxable year exceed the company’s current and accumulated earnings and profits which may be used for the payment of dividends on such class of stock, the company’s current earnings and profits shall, for purposes of subsection (a), be allocated first to distributions with respect to such class of stock made during the portion of the taxable year which precedes January 1. The amendments made by this section [enacting section 1022, redesignating former section 1022 as 1023, amending this section and sections 331, 333, 381, 541, 542, 543, 544, 545, 551, 553, 554, 562, 856, 1016, 1361, 6501, and the analysis preceding section 1011, and enacting provisions set out as a note under section 333 of this title ] (other than by subsections (c)(1), (f), (g), and (j) [enacting section 1022, redesignating former section 1022 as 1023, amending this section and sections 331, 333, 542, 551, 562, 1016, and the analysis preceding section 1011 of this title ]) shall apply to taxable years beginning after December 31, 1963 . The amendment made by subsection (c)(1) [amending section 542 of this title ] shall apply to taxable years beginning after October 16, 1962 . The amendments made by subsections (f) and (g) [amending this section and sections 331, 333, 551, and 562 of this title] shall apply to distributions made in any taxable year of the distributing corporation beginning after December 31, 1963 . The amendments made by subsection (j) [enacting section 1022, redesignating former section 1022 as 1023, and amending section 1016 and the analysis preceding section 1011 of this title ] shall apply in respect of decedents dying after December 31, 1963 . Subsection (h) [set out as a note under section 333 of this title ] shall apply to taxable years beginning after December 31, 1963 .”