Many families focus on making their estate plan as efficient as possible. For married couples, a key consideration is whether your plan takes full advantage of the federal portability rule a provision that can make a multimillion-dollar difference in what you leave behind. With the 2025 federal estate tax exemption at $13.99 million per person, portability allows a surviving spouse to inherit any unused exemption from their deceased partner, potentially doubling the tax shelter up to $27.98 million as a couple.
What Is Portability in Estate Planning?
In simple terms, portability is a federal tax rule that lets a surviving spouse add their deceased spouse’s unused estate tax exemption to their lifetime exemption. This wasn’t always possible. The rule was introduced in 2010 and became a permanent fixture in U.S. estate law thanks to the American Taxpayer Relief Act of 2012.
How Portability Works
Portability isn’t automatic; it requires action. After the first spouse passes away, the survivor (or their estate representative) must file IRS Form 706, the U.S. Estate Tax Return, within nine months of death (or within 15 months with an extension) even if the estate is below the taxable threshold and no tax is due. Filing this form officially transfers the Deceased Spousal Unused Exclusion (DSUE) to the survivor. For smaller estates not technically required to file, the IRS currently allows a special late filing window: In 2025, as long as the portability-only estate tax return is filed within five years of the spouse’s death, you can still elect portability.
Why Portability Can Matter-A Lot
If your family wealth is substantial but not evenly distributed between spouses, or if most assets are held in one person’s name, portability can shield millions more from future estate taxes. This is especially important as the current federal exemption is set to potentially drop (projected to about $7 million per spouse in 2026 unless Congress acts). Relying on portability can offer a valuable safety net for families with appreciating investments or late-in-life asset growth.
Portability is also simpler for many families, often sidestepping the need for complex trust structures just to use both spouses’ exemptions. Another benefit: assets passed directly to a spouse, who later dies, receive a stepped-up tax basis; twice this can minimize capital gains taxes for your heirs down the road.
Portability’s Limitations & What to Watch Out For
While powerful, the portability rule isn’t a perfect fit for every estate:
Only the regular federal estate and gift tax exemption is portable. State-level estate taxes and the federal generation-skipping transfer (GST) exemption are typically not covered. The amount you receive from your spouse’s DSUE isn’t indexed for inflation it can lose value over time.
Filing Form 706 for portability triggers extended IRS audit rights for your estate, so careful preparation is essential.
If you remarry, only the most recent deceased spouse’s unused exemption is portable. Large or complex estates may still require trusts beyond what portability alone can achieve, especially to address state taxes, protect heirs in blended families, or maximize efficiency for families worth more than the combined federal exemption.
Is Your Estate Plan Taking Advantage of Portability? A Quick Test
Are you and your spouse both U.S. citizens or residents?
Was Form 706 filed, or is it planned for the spouse who passed away?
Was the DSUE election timely (within nine months or under a current extension or relief window)?
If you live in a state with its own estate tax, have you considered how it fits into your broader plan?
Do you have special concerns such as second marriages, blended families, or unique asset types (like closely held businesses)?
Real-World Examples
If a spouse with an $8 million estate passes but no Form 706 is filed, the survivor accidentally loses the ability to shelter an additional $5.99 million from future estate tax. Prompt filing means that the unused exemption is preserved for the survivor.
For high-net-worth couples (e.g., $25 million and up), portability alone may be insufficient. Trusts and advanced strategies could be essential to cover assets beyond the federal exemptions and to address generational or state tax issues.
Key Takeaways
Portability is one of the most impactful but often overlooked tools in estate planning for married couples. Done right, it can protect millions in family wealth from unnecessary taxes. But it’s not automatic, and it’s not always enough, especially for large, multigenerational, or complex estates.
Next Steps: Brought to You by Viscounte Financial
At Viscounte Financial, we know that the details matter when it comes to building a lasting financial legacy. Our team believes that with careful planning today, you can face tomorrow with confidence. We pride ourselves on building enduring relationships based on mutual respect and transparency, no matter where you begin your journey.
If you’re unsure whether your estate plan is making the most of the portability rule or if your plan is ready for tomorrow’s tax law changes, now is the time to act. Connect with our experienced advisors for a personalized review and clear, actionable guidance. Let Viscounte Financial help you instill confidence into preserving your family’s future, so you can focus on what matters most.
This information is not intended to be a substitute for specific individualized tax or legal advice. We suggest that you discuss your specific situation with a qualified tax or legal advisor.
