The IRS issued Notice 2011-76 on September 13, 2011, extending the due date for Form 8939 from November 15, 2011 to January 17, 2012. This form must be filed by Estates of 2010 decedents electing out of the estate tax system and into the carryover basis system.
The IRS also noted that estates of 2010 decedents may file Form 4768 to extend the due date for the Form 706 from September 19, 2011 to March 19, 2012, and that no penalties will be imposed for late payment of tax before that date. Interest will still be assessed on late payments of tax, but the penalties will not apply.
See Notice 2011-76 for more details.