Generation-Skipping Tax Exemption: 2026 Amount, Allocation, and Inclusion Ratio

The generation-skipping tax exemption lets you move up to $15 million in 2026 to grandchildren or more distant generations without triggering the 40% federal generation-skipping transfer tax.¹² That figure is per person, so a married couple can shelter up to $30 million combined. The number is only half the story, though. The exemption generally has to be claimed on a tax return to work, it isn’t portable between spouses the way the estate tax exemption is, and the amount of exemption a transfer consumes depends on when you allocate it.

What the Exemption Protects Against

The generation-skipping transfer tax (GST tax) is a separate 40% federal tax that applies on top of the gift and estate tax. Congress added it so wealthy families couldn’t skip the tax that would normally hit as wealth passed through the children’s generation by leaving assets directly to grandchildren instead.

The tax applies to transfers reaching a “skip person,” meaning someone two or more generations below you. Children are not skip persons. Grandchildren and great-grandchildren are. For people outside your family, the test is age: anyone born more than 37½ years after you counts as a skip person.³

One important carve-out: if your child dies before you, that child’s children move up a generation for GST purposes. Transfers to those grandchildren are no longer generation-skipping, and no GST tax applies. The rule exists so families aren’t penalized when a generation is lost to early death.³

The 2026 Amount and Why It’s Permanent Now

Each individual’s GST exemption for 2026 is $15 million.¹ It’s unified with the gift and estate tax exemption, so the same $15 million covers all three. Spend some of it on a lifetime gift and you have less left for your estate; use some to shelter a transfer to a trust for grandchildren and you’ve used both gift and GST exemption at once.⁴

The exemption had been scheduled to drop by roughly half after December 31, 2025, when the Tax Cuts and Jobs Act doubling was set to expire. The One Big Beautiful Bill Act, signed on July 4, 2025, removed that sunset. The $15 million amount is now permanent, with inflation adjustments starting in 2027.¹

The Exemption Is Not Portable Between Spouses

This catches more families off guard than any other feature of the rules. The ordinary estate tax exclusion is portable: if the first spouse to die doesn’t use all of it, the survivor can inherit the leftover. The GST exemption works differently. Any portion the first spouse doesn’t use is lost at death.⁵

For a couple with $30 million in combined wealth, leaving the first spouse’s GST exemption unused can mean giving up $15 million of GST-free transfer capacity. Estate planners work around this in two main ways. The couple can fund separate trusts during life so each spouse’s exemption gets used. Alternatively, the first spouse’s estate plan can direct assets into a trust that uses that spouse’s GST exemption. A common tool is the reverse QTIP election, which lets the executor treat the first spouse as the transferor of a marital trust for GST purposes while the property still qualifies for the marital deduction.⁶

How to Actually Claim the Exemption

Having the exemption and applying it to a specific transfer are two different things. The exemption attaches to a transfer only when it’s allocated, and the rules differ depending on how you give.

Automatic Allocation

Some transfers get exemption applied without you doing anything. Direct outright gifts to a skip person (a direct skip) automatically draw exemption unless you file to opt out. Transfers to a trust that qualifies as a “GST trust,” generally any trust that could eventually benefit skip persons, also get automatic allocation. The automatic rules exist because forgetting to allocate is one of the most expensive mistakes in estate planning. If you don’t want the automatic allocation (for example, because the trust is unlikely to actually make skip transfers), you have to opt out on a timely gift tax return.⁷

Allocating on Form 709

For transfers that don’t trigger automatic allocation, you claim exemption on Form 709, the federal gift tax return, due April 15 of the year following the gift.⁸ Timely allocation is valuable because the property is valued at the date of transfer. Put $2 million into a trust in March, let it grow to $3 million before you file in April, and $2 million of exemption still covers the whole transfer.

At death, the executor allocates any remaining GST exemption on Form 706, the federal estate tax return. The executor can also clean up lifetime transfers the decedent never properly covered.⁷

The Cost of a Late Allocation

Miss the deadline and you can still allocate, but the property is valued on the date you make the late allocation. If the trust assets have grown from $2 million to $5 million since the original transfer, you now need $5 million of exemption to fully cover them. The appreciation your early allocation would have sheltered for free now costs you $3 million of exemption.

Relief for Missed Allocations

If you or your advisor simply forgot, the IRS provides a path to fix it under Section 2642(g). You have to show you acted reasonably and in good faith, and that relief wouldn’t prejudice the government. The IRS looks at whether contemporaneous documents show allocation was intended, whether a qualified tax professional was involved, and whether you’re trying to cherry-pick the trusts that happened to appreciate the most.⁹

There’s also a straightforward automatic six-month extension if you filed the return on time but left out the GST allocation. You file a supplemental return within six months, mark it as filed pursuant to the relief regulation, and pay no user fee. Beyond that window you’re into private letter ruling territory, with detailed affidavits and a filing fee.⁹

Transfers That Don’t Use Your Exemption

Not every gift to a grandchild eats into the $15 million. Gifts within the annual gift tax exclusion ($19,000 per recipient in 2026) are treated as fully GST-exempt when made as outright direct skips, so you can give each grandchild $19,000 a year with no GST tax and no exemption consumed.¹

Payments made directly to a school for tuition or to a medical provider for someone’s care are excluded from both gift tax and GST tax, with no dollar cap.

Annual exclusion gifts to a trust are trickier. The trust only gets the automatic GST exclusion if it benefits one single grandchild during their lifetime and the remaining assets are included in that grandchild’s estate if they die before the trust ends. Trusts with multiple grandchildren as beneficiaries, or discretionary pots, don’t qualify, and gifts to those trusts will consume GST exemption.¹⁰

What Allocating Exemption Actually Does: The Inclusion Ratio

When you allocate exemption to a trust or transfer, you’re setting its “inclusion ratio,” which determines the GST tax rate on every future transfer from that property. Divide the exemption allocated by the fair market value transferred to get the applicable fraction; one minus that fraction is the inclusion ratio.¹¹ GST tax on any future distribution from that property equals 40% times that ratio.

Three outcomes are possible. An inclusion ratio of zero means you allocated enough exemption to cover the full transfer, and every future distribution to skip persons is GST-free forever, including appreciation. This is why planners allocate exemption to trusts holding the assets with the most growth potential: $5 million in exemption used today can shelter a trust worth $50 million decades later. An inclusion ratio of one means no exemption was allocated and the full 40% applies on every generation-skipping transfer. A fractional ratio sits in between and creates a trust with a split tax identity that complicates every distribution. The usual fix is a qualified severance, dividing the trust into one wholly exempt trust and one wholly non-exempt trust with the same beneficiary terms.¹²

What Missing a Deadline Costs

When GST tax does come due, the payment deadline is firm. The failure-to-pay penalty is 0.5% of the unpaid balance per month or partial month, up to 25%, with interest running from the original due date. If the IRS issues a notice of intent to levy and you still don’t pay within 10 days, the monthly rate jumps to 1%.¹³ Extensions through Form 7004 give you more time to file but not more time to pay.¹⁴

At a 40% rate on seven- or eight-figure sums, the cost of getting allocation wrong eclipses almost any planning fee. Allocating on time, at today’s value, with both spouses’ exemptions used, is where the real money is saved.

1
Internal Revenue Service. What’s New – Estate and Gift Tax
2
eCFR. 26 CFR 26.2641-1 – Applicable Rate of Tax
3
Office of the Law Revision Counsel. 26 USC 2651 – Generation Assignment
4
Office of the Law Revision Counsel. 26 USC 2631 – GST Exemption
5
Congress.gov. The Generation-Skipping Transfer Tax (GSTT)
6
eCFR. 26 CFR 26.2652-2 – Special Election for Qualified Terminable Interest Property
7
Office of the Law Revision Counsel. 26 USC 2632 – Special Rules for Allocation of GST Exemption
8
Internal Revenue Service. Instructions for Form 709 (2025)
9
Federal Register. Relief Provisions Respecting Timely Allocation of GST Exemption and Certain GST Elections
10
Office of the Law Revision Counsel. 26 USC 2642 – Inclusion Ratio – Section 2642(c)
11
Office of the Law Revision Counsel. 26 USC 2642 – Inclusion Ratio
12
eCFR. 26 CFR 26.2642-6 – Qualified Severance
13
Internal Revenue Service. Failure to Pay Penalty
14
eCFR. 26 CFR 26.6081-1 – Automatic Extension of Time for Filing Generation-Skipping Transfer Tax Returns