Estate Planning · Haute Lawyer Network
What Is Portability of the Estate Tax Exemption?
Last reviewed: June 2026
Portability is a federal estate tax provision that allows a surviving spouse to use the deceased spouse's unused estate tax exemption — the Deceased Spousal Unused Exclusion (DSUE). Without portability, any unused exemption of the first spouse to die would simply be lost.
With portability, the surviving spouse can add the deceased spouse's unused exemption to their own, potentially sheltering up to $27.22 million from federal estate tax (using both the surviving spouse's $13.61 million exemption and the DSUE from the deceased spouse) in 2026.
To use portability, the deceased spouse's executor must timely elect portability on a federal estate tax return — Form 706 — within nine months of death (or 15 months with an extension), even if no estate tax is owed. Failing to file this return forfeits portability — permanently.
Frequently Asked Questions
Does portability apply to state estate taxes?
No. Portability is a federal provision only. States with their own estate taxes do not generally allow portability — each spouse's state exemption is used independently.
Is portability better than a bypass trust?
Both accomplish the goal of using both spouses' exemptions. Portability is simpler — no trust required. A bypass trust provides asset protection from the surviving spouse's creditors, locks in the exemption amount (protecting against future exemption reductions), and provides additional planning flexibility. Many estate planners recommend both strategies together.
What if the first spouse had already used some of their exemption through lifetime gifts?
The DSUE is the deceased spouse's remaining unused exemption after accounting for taxable gifts during their lifetime.
What if the surviving spouse remarries?
If the surviving spouse remarries and the second spouse predeceases them, the surviving spouse can only use the DSUE from the most recently deceased spouse — the DSUE from the first deceased spouse is forfeited upon remarriage and second predeceased spouse.
Do I need to file an estate tax return even if the deceased spouse's estate is below the exemption?
Yes — specifically to elect portability. The return does not have to report estate tax liability, but must be filed to preserve the DSUE for the surviving spouse's estate.
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