IRS Grants Extension for Portability Election Under § 2010(c)(5)(A)

IRS Grants 120-Day Extension for Portability Election: What Estates Need to Know

The IRS has granted a 120-day extension to an estate seeking to make a portability election under § 2010(c)(5)(A), preserving the surviving spouse’s ability to claim the deceased spouse’s unused estate tax exemption (DSUE). Without this election, the surviving spouse risks losing the DSUE amount—potentially millions in unclaimed tax exemptions—depending on the size of the decedent’s estate. The IRS ruled that the estate has 120 days from the date of this letter to file a complete Form 706 and make the election, though the ruling is non-precedential and becomes null if the estate is later determined to be required to file under § 6018(a).

The $X Million Mistake: Why the Estate Missed the Portability Election Deadline

The decedent died on Date, survived by their spouse. At the time of death, the estate’s gross estate value—after accounting for any taxable gifts—fell below the § 6018(a) filing threshold, which in 2026 is $13.61 million (indexed for inflation). Because the estate was not required to file Form 706 under § 6018(a), the executor did not file the return and did not make the portability election to transfer the decedent’s unused applicable exclusion amount (DSUE) to the surviving spouse.

The decedent’s estate included an unused portion of their applicable exclusion amount, calculated under § 2010(c)(4) as the lesser of (A) the basic exclusion amount or (B) the excess of the decedent’s applicable exclusion amount over the amount with respect to which the tentative tax was determined under § 2001(b)(1). This unused exclusion—potentially millions in unclaimed tax exemptions—could have been preserved for the surviving spouse’s future estate or gift tax planning. However, because no Form 706 was filed within the nine-month deadline prescribed by § 20.2010-2(a)(1), the election was never made.

The oversight was discovered months later, prompting the estate to submit a request under § 301.9100-3 for an extension of time to make the portability election. Without this election, the surviving spouse loses the ability to use the decedent’s DSUE, which could significantly increase their own estate tax liability when they later pass away. The missed election is not merely a procedural error—it represents a $X million mistake, as the surviving spouse forfeits a critical tax planning tool that could shield future transfers from estate tax.

IRS’s Rationale: Why the Extension Was Granted Under § 301.9100-3

The IRS grounded its decision in § 301.9100-3, which grants the Commissioner discretion to extend regulatory election deadlines when three conditions are met: the taxpayer acted reasonably and in good faith, the government’s interests are not prejudiced, and the request is filed within the prescribed timeframe. The regulation explicitly applies to elections whose due dates are set by regulation—such as the portability election under § 20.2010-2(a)(1), which requires filing Form 706 within nine months of a decedent’s death (or the extended deadline). The IRS emphasized that § 301.9100-3 operates independently of § 2010(c)(5)(A), which mandates that the portability election be made on a timely filed estate tax return. The regulation’s purpose is to mitigate harsh results where taxpayers miss deadlines due to circumstances beyond their control, provided the government suffers no harm.

The IRS concluded that the estate satisfied the reasonable and good faith standard under § 301.9100-3. The estate’s submission included detailed representations explaining the failure to timely file, demonstrating that the omission was not due to willful neglect but rather to a misunderstanding of the filing requirement or reliance on professional advice. The IRS did not require proof of extraordinary circumstances; instead, it evaluated whether the estate’s conduct reflected an honest effort to comply with the law. The agency noted that the estate’s actions did not involve any attempt to manipulate tax liability or conceal information, which would have prejudiced the government’s interests.

Under § 301.9100-1(c), the Commissioner’s authority to grant extensions is discretionary and applies broadly to regulatory elections across the Internal Revenue Code, with limited exceptions. The IRS acknowledged that portability elections fall squarely within this framework because the deadline is set by regulation, not statute. The agency’s decision to grant a 120-day extension was explicitly tied to the estate’s ability to demonstrate compliance with § 301.9100-3’s requirements. The IRS cautioned, however, that the extension would be nullified retroactively if it were later determined that the estate was required to file Form 706 under § 6018(a)—meaning the gross estate exceeded the filing threshold. In such a case, the portability election would have been mandatory, and the late filing would not qualify for relief under § 301.9100-3.

The IRS’s analysis hinged on the distinction between estates required to file Form 706 and those electing to file solely for portability. For estates below the § 6018(a) threshold, the portability election is optional, and the IRS’s discretionary relief under § 301.9100-3 provides a safety net for those who miss the deadline. The agency’s willingness to grant the extension reflects a policy favoring substantive compliance over technical defaults, provided the taxpayer meets the regulation’s conditions. This approach aligns with broader IRS guidance, including Rev. Proc. 2022-32, which expanded relief for late portability elections to five years in certain cases, underscoring the agency’s flexibility where no prejudice to the government exists.

How to Comply: Filing Requirements and Next Steps for the Estate

The IRS granted a 120-day extension under § 301.9100-3 to file the portability election, but the estate must now meet strict filing requirements to preserve the relief. The election must be made by submitting a complete and properly prepared Form 706—the U.S. Estate Tax Return—along with a copy of this Private Letter Ruling (PLR-119656-25) within 120 days of the letter’s date. The IRS explicitly stated that a Form 706 filed by this deadline "will be considered to be timely filed" for portability purposes, provided the estate meets the conditions of § 301.9100-3.

The filing must be sent to the Kansas City IRS Service Center at: Department of the Treasury, Internal Revenue Service Center, Kansas City, MO 64999

Crucially, the IRS warned that if the estate’s gross estate plus adjusted taxable gifts exceeds the filing threshold under § 6018(a)—currently $13.61 million for 2026—the Commissioner lacks authority to grant the extension, rendering it "null and void." The estate must therefore ensure its Form 706 is accurate and complete, including all required schedules and the portability election statement, to avoid disqualification. Any omission or error could result in the IRS deeming the extension ineffective, leaving the surviving spouse without access to the deceased spouse’s unused exemption.

Implications for Other Estates: When Can Taxpayers Rely on This Ruling?

The IRS’s grant of a 120-day extension under § 301.9100-3 in this ruling offers temporary relief for estates in similar circumstances, but it does not create binding precedent. Section 6110(k)(3) explicitly states that Private Letter Rulings (PLRs) may not be cited or relied upon as precedent by other taxpayers. The IRS’s decision in this case was based on the estate’s specific facts and representations, including the submission of a penalty of perjury statement. Other estates cannot assume identical treatment unless they present identical circumstances to the IRS for a new ruling.

The IRS also emphasized that the Deceased Spousal Unused Exclusion (DSUE) amount remains subject to substantiation and audit. The agency noted that any claimed DSUE amount will only be included in the surviving spouse’s applicable exclusion amount "to the extent that Spouse can substantiate such amount" and will be "subject to determination by the Director’s office upon audit of relevant Federal gift or estate tax returns." This means estates relying on this ruling must maintain comprehensive records of the deceased spouse’s estate tax calculations, valuations, and supporting documentation to withstand potential IRS scrutiny.

Estates that assume they are not required to file Form 706 under § 6018(a)—even when the gross estate falls below the filing threshold—risk losing the portability election entirely. The IRS’s position in this ruling underscores that portability is not automatic; it requires an explicit election on a properly filed Form 706. The estate in this case sought an extension because it initially believed it was exempt from filing, only to later discover that the absence of a timely election forfeited the DSUE benefit. This highlights a critical risk: misjudging filing requirements can result in irreversible tax consequences for surviving spouses.

To avoid similar pitfalls, estates should adopt proactive compliance practices. Consulting with a tax professional familiar with estate tax filings is essential, particularly when the estate’s value hovers near the § 6018(a) threshold. Executors must also closely review IRS instructions for Form 706, ensuring the portability election statement is included and accurate. Even estates below the filing threshold should consider voluntary filing to preserve the DSUE, as the IRS has confirmed in recent guidance that such filings are permissible solely for portability purposes.

The broader lesson is clear: timely estate tax planning is not optional. The IRS’s willingness to grant relief in this case should not be interpreted as an invitation to delay critical filings. With the applicable exclusion amount set to sunset in 2026, estates must act decisively to secure their tax planning objectives before legislative changes take effect. Failure to do so risks leaving surviving spouses without access to a valuable tax benefit—one that, once lost, cannot be recovered.