Procedures for requesting an extension of time for filing the return. A request for an extension of time to file the return required by section 6018 must be made by filing Form 4768, “Application for Extension of Time To File a Return and/or Pay U.S. Estate (and Generation-Skipping Transfer) Taxes.” Form 4768 must be filed with the Internal Revenue Service office designated in the application's instructions (except as provided in § 301.6091-1(b) of this chapter for hand-carried documents). Form 4768 must include an estimate of the amounts of estate and generation-skipping transfer tax liabilities with respect to the estate.

Automatic extension. An estate will be allowed an automatic 6-month extension of time beyond the date prescribed in section 6075(a) to file Form 706, “United States Estate (and Generation-Skipping Transfer) Tax Return,” if Form 4768 is filed on or before the due date for filing Form 706 and in accordance with the procedures under paragraph (a) of this section.

Extension for good cause shown. In its discretion, the Internal Revenue Service may, upon the showing of good and sufficient cause, grant an extension of time to file the return required by section 6018 in certain situations. Such an extension may be granted to an estate that did not request an automatic extension of time to file Form 706 prior to the due date under paragraph (b) of this section, to an estate or person that is required to file forms other than Form 706, or to an executor who is abroad and is requesting an additional extension of time to file Form 706 beyond the 6-month automatic extension. Unless the executor is abroad, the extension of time may not be for more than 6 months beyond the filing date prescribed in section 6075(a). To obtain such an extension, Form 4768 must be filed in accordance with the procedures under paragraph (a) of this section and must contain a detailed explanation of why it is impossible or impractical to file a reasonably complete return by the due date. Form 4768 should be filed sufficiently early to permit the Internal Revenue Service time to consider the matter and reply before what otherwise would be the due date of the return. Failure to file Form 4768 before that due date may indicate negligence and constitute sufficient cause for denial of the extension. If an estate did not request an automatic extension of time to file Form 706 under paragraph (b) of this section, Form 4768 must also contain an explanation showing good cause for not requesting the automatic extension.

Filing the return. A return as complete as possible must be filed before the expiration of the extension period. The return thus filed will be the return required by section 6018(a), and any tax shown on the return will be the amount determined by the executor as the tax referred to in section 6161(a)(2), or the amount shown as the tax by the taxpayer upon the taxpayer's return referred to in section 6211(a)(1)(A). The return cannot be amended after the expiration of the extension period although supplemental information may subsequently be filed that may result in a finally determined tax different from the amount shown as the tax on the return.

Payment of the tax. An extension of time for filing a return does not operate to extend the time for payment of the tax. See § 20.6151-1 for the time for payment of the tax, and §§ 20.6161-1 and 20.6163-1 for extensions of time for payment of the tax. If an extension of time to file a return is obtained, but no extension of time for payment of the tax is granted, interest will be due on the tax not paid by the due date and the estate will be subject to all applicable late payment penalties.

Effective date. This section applies to estates of decedents dying after August 16, 1954, except for paragraph (b) of this section which applies to estate tax returns due after July 25, 2001.