((a)) ** General rule** In the case of returns under section 6012, 6013, or 6017 (relating to income tax under subtitle A), returns made on the basis of the calendar year shall be filed on or before the 15th day of April following the close of the calendar year and returns made on the basis of a fiscal year shall be filed on or before the 15th day of the fourth month following the close of the fiscal year, except as otherwise provided in the following subsections of this section.

((b)) ** Returns of partnerships and S corporations** Returns of partnerships under section 6031 and returns of S corporations under sections 6012 and 6037 made on the basis of the calendar year shall be filed on or before the 15th day of March following the close of the calendar year, and such returns made on the basis of a fiscal year shall be filed on or before the 15th day of the third month following the close of the fiscal year. Returns required for a taxable year by section 6011(c)(2) (relating to returns of a DISC) shall be filed on or before the fifteenth day of the ninth month following the close of the taxable year.

((c)) ** Returns by certain nonresident alien individuals and foreign corporations** Returns made by nonresident alien individuals (other than those whose wages are subject to withholding under chapter 24) and foreign corporations (other than those having an office or place of business in the United States or a former FSC (as defined in section 922 as in effect before its repeal by the FSC Repeal and Extraterritorial Income Exclusion Act of 2000)) under section 6012 on the basis of a calendar year shall be filed on or before the 15th day of June following the close of the calendar year and such returns made on the basis of a fiscal year shall be filed on or before the 15th day of the 6th month following the close of the fiscal year.

((d)) ** Returns of cooperative associations** In the case of an income tax return of—

((1)) an exempt cooperative association described in section 1381(a)(1), or

((2)) an organization described in section 1381(a)(2) which is under an obligation to pay patronage dividends (as defined in section 1388(a)) in an amount equal to at least 50 percent of its net earnings from business done with or for its patrons, or which paid patronage dividends in such an amount out of the net earnings from business done with or for patrons during the most recent taxable year for which it had such net earnings,

((e)) ** Organizations exempt from taxation under section 501(a)** In the case of an income tax return of an organization exempt from taxation under section 501(a) (other than an employees’ trust described in section 401(a)), a return shall be filed on or before the 15th day of the 5th month following the close of the taxable year.