Each person has a lifetime exemption from estate and gift tax. When the first spouse in a couple dies, their exemption may be largely unused — everything passed to the surviving spouse, which is generally not taxable.
Portability lets the survivor claim that unused amount, effectively doubling their own exemption. It is valuable, straightforward in principle, and requires an affirmative election that families frequently fail to make.
What changed in 2026
- The scheduled exemption reduction stayed prominent. A future decrease in the exemption amount increased the value of preserving every available portion.
- The extended filing window remained available. Relief for estates not otherwise required to file continued, within limits.
- Awareness stayed inconsistent. Missed elections continued to occur, particularly where no professional was involved.
- The generation-skipping gap persisted. That exemption remained non-portable, which continued to catch families.
The election requirement
The unused exemption does not transfer automatically. It transfers only if an estate tax return is filed for the deceased spouse and the election is made on it.
That is the part that gets missed. An estate below the filing threshold has no obligation to file — so the family, quite reasonably, does not. And the unused exemption is forfeited.
The loss can be very large, and it becomes apparent only years later when the survivor's estate is settled and the doubled exemption is not available.
There is relief: an extended window exists for estates that were not otherwise required to file, allowing a late election. It is limited in duration and subject to conditions, so it is a safety net rather than a plan.
The practical rule: when the first spouse dies, consider filing to elect portability even if no filing is required. The cost of preparing the return is small relative to the exemption at stake.
What portability does and does not cover
|
Portable? |
| Unused estate and gift tax exemption |
Yes, with election |
| Generation-skipping transfer exemption |
No |
| State-level exemptions |
Varies by state; frequently not |
| Exemption already used by lifetime gifts |
Only the unused portion transfers |
The generation-skipping gap matters for families planning transfers to grandchildren. That exemption is separate, and it is not portable — an unused generation-skipping exemption simply disappears when the first spouse dies.
Families with multi-generational plans therefore may need trust structures to use the first spouse's generation-skipping exemption rather than relying on portability, which does nothing for it.
State treatment varies too. Some states with their own estate tax do not recognise portability, so a trust structure may still be needed for state purposes even where federal portability suffices.
Portability versus trusts
Before portability, the standard approach used a trust at the first death to capture the exemption. Portability made simpler arrangements viable for many families.
Trusts still offer things portability does not:
Growth outside the estate. Assets in a properly structured trust grow outside the survivor's estate, so appreciation escapes tax. A ported exemption is a fixed amount that does not grow.
Control over the eventual disposition. A trust can direct where assets go after the survivor's death, which matters in blended families.
Creditor and remarriage protection for the survivor's benefit.
Generation-skipping exemption use, which portability cannot provide.
Portability offers simplicity, a full basis step-up at the second death on assets in the survivor's estate, and no trust administration.
Which is better depends on the size of the estate, expected growth, family structure, and state rules — a genuine planning question rather than a default.
Common mistakes
- Not filing to elect portability. The dominant and most expensive error.
- Assuming a small estate means no action. Filing may still be worthwhile.
- Relying on portability for generation-skipping. It does not apply.
- Ignoring state-level rules. They may not follow federal portability.
- Missing the extended relief window. It is limited.
- Assuming the ported amount grows. It is fixed at the first death.
- Not revisiting the plan after remarriage. It affects which exemption is available.
FAQ
How long do I have to elect?
An estate tax return is normally due within months of death with extension available. For estates not otherwise required to file, an extended window for a late portability election exists. Do not rely on it as a plan.
What if the survivor remarries?
The ported amount is generally tied to the last deceased spouse, so remarriage and a subsequent death can change what is available. Worth reviewing on remarriage.
Does the ported amount grow with inflation?
No — it is fixed at the first spouse's death. The survivor's own exemption continues to adjust; the ported portion does not. That is a meaningful argument for trust structures in growing estates.
Is this relevant if our estate is well below the exemption?
The exemption is scheduled to reduce, and estates grow. Preserving the amount costs a filing; forfeiting it is irreversible.
Where to go next
For lifetime transfers that use the exemption, read gift splitting. For the basis consequences at death, step-up basis explained, and for beneficiary designations that pass outside the estate, beneficiary audit.
This is general information, not legal or tax advice. Estate rules vary by state and are scheduled to change; consult a qualified professional.