26 CFR § 1.6081-5 - Extensions of time in the case of certain partnerships, corporations and U.S. citizens and residents.
(a) An extension of time for filing returns of income and for paying any tax shown on the return is hereby granted to and including the fifteenth day of the sixth month following the close of the taxable year in the case of -
(1) [Reserved]. For further guidance, see § 1.6081-5T(a)(1);
(b) In order to qualify for the extension under this section -
(2) If a person described in paragraph (a) of this section requests additional time to file, the person must request the extension on or before the fifteenth day of the sixth month following the close of the taxable year and check the appropriate box on Form 4868, “Application for Automatic Extension of Time To File a U.S. Individual Income Tax Return,” or Form 7004, “Application for Automatic Extension of Time to File Certain Business Income Tax, Information, and Other Returns,” whichever is applicable, or in any other manner prescribed by the Commissioner.
(c) For purposes of paragraph (a)(5) of this section, whether a person is a United States resident will be determined in accordance with section 7701(b) of the Code. The term “tax home,” as used in paragraph (a)(5), will have the same meaning which it has for purposes of section 162(a)(2) (relating to travel expenses away from home). If a person does not have a regular or principal place of business, that person's tax home will be considered to be his regular place of abode in a real and substantial sense.
(d) In order to qualify for the extension under paragraph (a)(6), the assigned tour of duty outside the United States and Puerto Rico must be for a period that includes the entire due date of the return.
(e) A person otherwise qualifying for the extension under paragraph (a)(5) or paragraph (a)(6) shall not be disqualified because he is physically present in the United States or Puerto Rico at any time, including the due date of the return.