The IRS released new final estate and gift tax regulations that include guidance on taxpayers seeking so-called “portability” elections to carry over the lifetime exclusion from the first spouse to die to the second spouse.  The new rules require a formal private letter ruling request under Section 9100 to request permission of the IRS to waive the missed election that would have been filed on the estate tax return of the first spouse to die. The relief is only applicable if no estate tax return was required on the death of the first spouse.  The new rules replace the simplified portability election relief found in Rev. Proc. 2014-18.