The timing was critical, as 2010 estate tax returns for decedents dying on or before 12/16/2010 were due Monday, September 19, 2011. Estate tax returns are normally due nine months after death, but there was an exception because of last year’s tax law flux.
Remember there was no estate tax for most of 2010. On December 17, 2010, the President signed a tax bill that reinstated the estate tax retroactively to January 1, 2010. That law set a 35% estate tax rate and provided an estate tax exemption of $5 million. The advantage to this scheme is that estate assets get “stepped-up” to their fair market value at the date of death. This means that the inheritors can (generally) sell the assets right away without incurring any income tax. To complicate matters, the bill also made this scheme an option for 2010. Estates of 2010 decedents could opt out of the new tax and use a modified basis carryover regime. There would be no estate tax, but the heirs received the same basis in assets as the decedent (with a $3 million exception for the surviving spouse and a $1.3 million exception for non-spousal beneficiaries). This opt-out required the beneficiaries to know the carryover basis in the assets inherited, so the IRS created a new form (Form 8939 - Allocation of Increase in Basis for Property Acquired From a Decedent). Opting-out of the estate tax is an irrevocable election.
As I write this, the IRS has not finalized Form 8939, although a draft version is available.
The IRS is providing the following filing relief: