26 CFR § 1.6016-1 - Declarations of estimated income tax by corporations.
(a) Requirement. For taxable years ending on or after December 31, 1955, a declaration of estimated tax shall be made by every corporation (including unincorporated business enterprises electing to be taxed as domestic corporations under section 1361), which is subject to taxation under section 11 or 1201(a), or subchapter L, chapter 1 of the Code (relating to insurance companies), if its income tax under such sections or such subchapter L for the taxable year can reasonably be expected to exceed the sum of $100,000 plus the amount of any estimated credits allowable under section 32 (relating to tax withheld at source on nonresident aliens and foreign corporations and on tax-free covenant bonds), section 33 (relating to taxes of foreign countries and possessions of the United States), and section 38 (relating to investment in certain depreciable property).
(b) Definition of estimated tax. The term “estimated tax”, in the case of a corporation, means the excess of the amount which such corporation estimates as its income tax liability for the taxable year under section 11 or 1201(a), or subchapter L, chapter 1 of the Code, over the sum of $100,000 and any estimated credits under sections 32, 33, and 38. However, for the rule with respect to the limitation upon the $100,000 exemption for members of certain electing affiliated groups, see section 243(b)(3)(C)(v) and the regulations thereunder.
(c) Examples. The application of this section may be illustrated by the following examples: