Silicon Valley has a new favorite wealth transfer strategy, and the IRS has noticed.
It’s called “trust stacking.” The idea is elegantly aggressive: use multiple layers of trusts — often across different jurisdictions, with interconnected ownership structures and valuation discounts at each level — to multiply the estate and gift tax exemption far beyond what Congress intended. One $15 million exemption becomes, in theory, two. Or three. Or more.
The IRS does not like it. And if you are a trustee administering a structure that looks anything like this, you need to understand what is coming.
What is trust stacking?
Trust stacking is not a single documented technique with a uniform definition. It is an umbrella term that has emerged in estate planning circles — particularly among tech entrepreneurs and the advisors who serve them — for strategies that use layered trust structures to amplify the federal estate and gift tax exemption.
Here is how a typical structure works in practice:
Layer 1: The grantor funds an irrevocable trust with $15 million — the current permanent federal estate and gift tax exemption. The trust purchases interests in a family entity (typically an LLC or limited partnership) at a discounted valuation. The discount might reflect lack of marketability, minority interest, or other fractional-ownership adjustments. A $15 million contribution buys, say, $20 million in underlying asset value after discounts.
Layer 2: The first trust distributes interests to a second trust — often in a different state with more favorable self-settled asset protection laws or more flexible directed trustee provisions. The second trust applies its own set of valuation discounts. The same underlying assets are now discounted again.
Layer 3: A third trust receives distributions from the second, often through a combination of GST-exempt structures, installment sales to grantor trusts, or leveraged gifting techniques. Each layer applies its own discount or exemption claim.
The result, on paper, is that a single $15 million exemption effectively shields many multiples of that amount. Some practitioners have marketed structures claiming to multiply exemption value three, four, or even five times.
That is the theory. In practice, the IRS views this as an abuse of the exemption system — not a creative interpretation of it.
Why the IRS is targeting trust stacking now
Several factors have converged to put trust stacking in the IRS crosshairs:
The Working Families Tax Cuts Act of 2025 permanently set the exemption at $15 million. Before the law changed, exemption levels were scheduled to sunset and there was political pressure to use aggressive planning before thresholds dropped. When Congress instead locked the exemption at $15 million per person (indexed for inflation), the rationale for extreme leveraging strategies weakened. The exemption is permanent. The urgency that drove some clients into aggressive structures was manufactured, not real — but the structures remain.
The IRS has rebuilt its enforcement capacity. After years of budget cuts that hollowed out the estate and gift tax examination function, the IRS has been rebuilding. The agency’s 2026 filing season processed nearly 139 million individual returns successfully, and the National Taxpayer Advocate’s mid-year report to Congress noted expanded enforcement capabilities across multiple divisions. Trust and estate examination is part of that rebuild.
Machine learning is now flagging patterns, not just returns. As we noted in our IRS trust audit triggers analysis, the IRS is using AI to detect behavioral anomalies in trust returns. Trust stacking creates a distinctive footprint: multiple related trusts filing separate Form 1041s, inter-trust distributions, recurring valuation discount claims on related-party transfers, and GST exemption allocations that appear to exceed the grantor’s available exemption when aggregated across structures. These are exactly the patterns that automated examination systems are designed to catch.
The Connelly decision changed the valuation landscape. In Connelly v. United States (2024), the Supreme Court held that life insurance proceeds payable to a corporation to fund a redemption obligation were included in the deceased shareholder’s gross estate. The decision sent shockwaves through the estate planning community because it rejected the argument that a redemption obligation offset the insurance proceeds for estate tax purposes. For trust stacking, the implications are significant: many stacked structures rely on life insurance-owned entities or cross-owned interests where the Connelly logic could apply to increase the taxable estate despite the trust layers. The IRS now has a Supreme Court precedent that undermines the “the trust owns it, not the estate” defense that stacked structures depend on.
The specific risks for trustees
If you are a trustee — whether you set up the structure or inherited it — trust stacking creates several distinct categories of risk:
1. Audit risk that extends to every layer
When the IRS examines a trust stacking structure, it does not look at one trust in isolation. It follows the chain. A Form 1041 filing for the first-layer trust triggers questions about distributions. Those questions lead to the second-layer trust’s returns. Those lead to the third. Each trust’s records, valuations, and exemption allocations are potentially exposed.
If you are the trustee of even one layer in a stacked structure, your records are now part of an examination you may not have known was coming. And if your records are the weakest link — missing valuations, undocumented distribution decisions, incomplete meeting minutes — the IRS will start there.
2. Valuation challenge risk
Trust stacking depends on valuation discounts at each layer. Each discount claim is independently challengeable. The IRS can attack any discount that lacks a contemporaneous, independent, qualified appraisal. And under the new fair value measurement standards, the documentation expectations for nonfinancial asset valuations have increased.
If your trust claimed a 35% lack-of-marketability discount on an LLC interest transfer in 2023 and you cannot produce the appraisal that supported it, the IRS can disallow the discount retroactively. That changes the economics of every downstream layer.
3. GST exemption allocation errors
Multiple recent private letter rulings — LTR 202625001, 202625006, and 202625016, all issued June 29, 2026 — granted extensions to allocate generation-skipping transfer (GST) tax exemption. This wave of rulings signals that practitioners are scrambling to correct GST allocations, and that the IRS is paying close attention to whether allocations were timely, properly computed, and correctly reported.
In a stacked structure, GST exemption is allocated at each layer. If one layer’s allocation was late, understated, or applied to the wrong trust, the entire GST-exempt status of the downstream structure may be compromised. A trust that was supposed to be fully GST-exempt could end up partially or fully subject to GST tax — a 40% tax on transfers to skip-generation beneficiaries.
4. Fiduciary liability for imprudent structures
Here is the risk most trustees underestimate. If you are administering a trust that was designed as part of a stacking strategy and the IRS challenges the structure, your beneficiaries will look to you — the fiduciary — for answers. If the challenge results in additional tax, penalties, or interest, beneficiaries may argue that the trustee should have:
- Questioned the structure’s sustainability before accepting the trusteeship
- Sought independent counsel to evaluate the stacking strategy
- Documented the fiduciary’s review of the estate tax positions
- Recommended unwinding or simplifying the structure when audit risk increased
- Preserved and produced the valuation support that the structure depended on
A trustee who passively administers a stacked structure without questioning its tax positions is exposed to the same kind of surcharge risk we have seen courts expand over the past year. The standard is not whether the trustee created the problem. It is whether the trustee took reasonable steps to identify and mitigate it.
5. State-level scrutiny
Several states have begun examining whether trust stacking structures that use self-settled asset protection trusts (particularly in South Dakota, Nevada, and Delaware) are being used to evade state estate or inheritance taxes. A structure that passes federal muster may still trigger state-level challenges, especially where the grantor, trustee, and beneficiaries are in a state with an estate tax that does not conform to the federal $15 million exemption.
Connecticut, for example, has an active estate and gift tax with a much lower effective exemption. New York’s estate tax has its own cliff provision. If a stacked structure was designed for federal exemption multiplication but ignored state-level consequences, the trustee may face a state audit that the federal structure was never designed to withstand.
What trustees should do now
If you administer a trust that might be part of a stacked structure — or a trust with layered discounts, inter-trust distributions, or multiple related entities — here is the practical action plan:
Step 1: Map the full structure
Do not look at your trust in isolation. Trace every distribution, every entity ownership interest, and every related trust. Build a diagram that shows the complete ownership chain from the original grantor contribution through every trust layer, entity, and downstream beneficiary. If you cannot build this map from existing records, that itself is a red flag.
Step 2: Verify every valuation
For each trust layer that claimed a valuation discount, locate the contemporaneous appraisal. Confirm it was prepared by a qualified, independent appraiser. Check that the appraisal methodology would withstand IRS challenge under current standards. If the appraisal is missing, stale, or was prepared by a related party, flag it for remediation.
Step 3: Audit GST exemption allocations
Pull the Form 709 gift tax returns and check that GST exemption was allocated correctly at each layer. Verify that allocations were timely (within the allowable period) and that the allocated amounts match the actual transfers. If any allocation appears incorrect or late, consult with estate tax counsel about whether a late allocation election or ruling request is available.
Step 4: Evaluate whether to simplify
Some stacked structures can be unwound or simplified before an audit hits. If the economic benefit of the stacking is marginal relative to the audit risk, a trustee’s duty of prudence may actually require simplification. Document the analysis: what the structure was designed to achieve, what it is actually achieving, what the audit risk is, and what the cost of unwinding would be. That documentation is your fiduciary armor if anyone later asks why you did or did not act.
Step 5: Bring your documentation to audit-ready standards
This is where most trustees are most exposed. A stacked structure multiplies documentation requirements. Each trust layer needs its own:
- Form 1041 filings, reconciled with trust accounting records
- Distribution decisions documented with the level of formality that survives audit
- Valuation support for every related-party transfer
- GST allocation records traceable to the gift tax returns
- Inter-trust correspondence showing the basis for each distribution direction
- Trustee meeting minutes that reflect consideration of the tax positions
If your records are scattered across email threads, Word documents, and filing cabinets, you do not have documentation. You have a collection of notes. The difference matters when the IRS is sitting across the table.
How TrustOffice helps
Trust stacking creates a governance problem that no spreadsheet can solve. When a structure spans multiple trusts, multiple entities, and multiple valuation events, the documentation requirements exceed what any individual trustee can track manually.
TrustOffice gives trustees a single system of record for the entire structure. Map every trust, every entity, every distribution, and every valuation in one place. Link inter-trust transfers so a distribution from Layer 1 to Layer 2 is documented on both sides simultaneously. Attach valuations, appraisals, and exemption allocations directly to the transactions they support.
TrustOffice’s audit trail is built for exactly this scenario. Every decision, every document, every communication is timestamped and attributable. When the IRS asks who approved the distribution, what valuation was relied upon, and when the GST allocation was made, the answer is one click away — not a search through five years of email.
TrustOffice’s compliance workflows keep GST allocations, Form 1041 filings, and distribution documentation aligned. Set reminders for allocation deadlines. Flag distributions that lack valuation support. Require approval workflows for inter-trust transfers. The system enforces the discipline that trust stacking structures demand but that most trustees apply inconsistently.
TrustOffice’s beneficiary communication tools create the record that protects you. When beneficiaries ask why the trust is structured this way, the answer should be documented. When you recommend simplification, the recommendation should be logged. When you seek independent counsel’s review, the engagement and conclusions should be preserved. TrustOffice makes that the default, not an afterthought.
The bottom line
Trust stacking was designed to multiply exemptions. The IRS is now designing enforcement to catch it. If you are a trustee in a stacked structure, you are standing in the gap between an aggressive planning strategy and a rebuilding enforcement apparatus.
The trustees who will weather this are the ones who can prove — with contemporaneous, organized, defensible records — that they understood the structure, evaluated the risk, documented their decisions, and acted prudently throughout. The ones who will not are the ones who assumed the structure would never be examined and kept records accordingly.
The IRS has the tools. The precedent is building. The question is whether your documentation is ready.
Start with a structure review. Map your trust’s position in any stacked arrangement. Verify your valuations. Check your GST allocations. Then ask whether the complexity is worth the risk — and document the answer either way.
Request a TrustOffice demo to see how integrated trust governance, compliance tracking, and audit-ready documentation can protect you across every layer of your trust structure.
