Forbes.com: On September 13, 2011, the IRS released Notice 2011-76, which gives executors of estates of 2010 decedents more time to make an informed decision about whether to stay in the default estate tax regime for 2010 or opt out of the estate tax entirely.

The estate tax was repealed for most of 2010. But on December 17, 2010, President Obama signed a law that reinstated the estate tax retroactive to January 1, 2010. This law set the estate tax at a rate of 35% and provided an estate tax exemption of $5 million.

In a move that helped wealthy beneficiaries, including the beneficiaries of some billionaires, lawmakers made the estate tax in 2010 an optional, default regime. Executors of the estates of 2010 decedents can opt out of the estate tax by filing a special form—Form 8939 (Allocation of Increase in Basis for Property Acquired From a Decedent).