The IDGT Installment Sale Playbook: Freezing Estate Value, Burning Through Income Taxes, and Surviving Rev. Rul. 2023-2

Picture this scenario. A founder owns 40% of a fast-growing software company worth $20 million. Conservative projections show that stake hitting $80 million within a decade. Without planning, $60 million of pure appreciation will sit inside her taxable estate, exposed to a 40% federal estate tax — a $24 million bill her family will scramble to pay in cash within nine months of her death.

Now picture an alternative. She sells that same 40% stake today to an irrevocable trust she set up for her children, takes back a 9-year promissory note at the IRS-published interest rate, and pays the trust's income tax bill from her own checkbook for the rest of her life. A decade later, the company is worth $200 million. The note has been paid off. Her estate contains exactly the cash payments she received — nothing more. The other $128 million of growth sits inside the trust, outside her estate, ready to pass to her kids gift- and estate-tax free.

That is the Intentionally Defective Grantor Trust (IDGT) installment sale strategy in one paragraph. It is one of the most powerful — and most misunderstood — wealth transfer techniques in the U.S. tax code. It is also under more IRS scrutiny than ever, thanks to a 2023 Revenue Ruling that quietly killed a popular basis-step-up shortcut. Here is how it actually works, who it is for, and the traps that turn elegant planning into catastrophic results.

What "Intentionally Defective" Actually Means

The name sounds like a malpractice lawsuit waiting to happen. It is not. The "defect" is deliberate, and it is the entire point of the structure.

Two parallel tax systems govern transfers in the United States:

• The estate and gift tax system, which taxes wealth moving between generations.
• The income tax system, which taxes earnings each year.

Most trusts you hear about are treated the same way under both systems. A revocable living trust is part of your estate and you pay tax on its income. An ordinary irrevocable trust is outside your estate and pays its own income tax.

An IDGT splits the two. By drafting in specific powers — most commonly the "power to substitute property of equivalent value" under IRC §675(4)(C) — the trust is treated as owned by the grantor for income tax purposes but completed and outside the estate for transfer tax purposes. It is "defective" only relative to one tax regime; it is perfectly intact for the other.

The consequence: the grantor pays the trust's income tax every year, and those payments are not treated as additional gifts. They simply transfer wealth tax-free to the trust beneficiaries year after year. Estate planners call this the "tax burn." It is arguably the single most valuable feature of grantor trust planning.

The Sale Mechanic: Why You Sell Instead of Gift

If you simply gift assets to an irrevocable trust, the transfer counts against your lifetime gift tax exemption (currently $13.99 million per person in 2025, but scheduled to drop). Once you blow through the exemption, gifts trigger a 40% federal gift tax.

A sale to a grantor trust is treated very differently. Because the trust and the grantor are the same taxpayer for income tax purposes, the sale is effectively to yourself. No capital gain is recognized, and no gift is made — provided the trust pays you full and adequate consideration in the form of a promissory note bearing interest at least equal to the IRS Applicable Federal Rate (AFR) for the loan's term.

The economics depend on a single bet: will the asset appreciate faster than the AFR? If yes, every dollar of excess return accrues inside the trust, free of future estate tax. If no, you have created a slightly worse outcome than doing nothing. Given that long-term AFRs typically run a few percentage points below market expected returns for equity, real estate, and operating businesses, the strategy works in most realistic scenarios — but it is not free money.

The Five Components of an IDGT Sale

A textbook installment sale has five moving parts. Skip any one and the whole structure collapses.

1. A properly drafted IDGT. Must be irrevocable for transfer tax purposes but contain at least one grantor trust trigger from IRC §§671–679. Power of substitution is the most common and least intrusive choice.
2. A seed gift. The trust needs equity of its own — typically at least 10% of the value of assets being sold — before any installment sale is layered on top. Without seed equity, the IRS can argue the "loan" is really a retained interest under §2036, dragging everything back into the estate.
3. The asset being sold. Often closely-held business interests, FLP/LLC units, or appreciating real estate. Discounted entities (FLPs and LLCs) are popular because lack-of-marketability and lack-of-control discounts can shave 25–35% off the price the trust pays.
4. A promissory note at the appropriate AFR. Short-term (≤3 years), mid-term (3–9 years), or long-term (>9 years), each with its own published rate. The note must be commercially reasonable: amortization schedule, payment dates, and remedies for default.
5. Documented, observed formalities. Real notes, real bank accounts, real payments. The grantor must actually receive interest payments. Trust must keep books. If you treat the structure casually, the IRS will treat it as a sham.

The Math, Walked Through

Assume an asset worth $10 million today, expected to grow at 8% per year, and a 9-year mid-term AFR of 4.5%.

• Seed gift: $1 million in cash (uses $1 million of lifetime gift exemption).
• Sale: $10 million of the asset, payable via 9-year interest-only note at 4.5% with a balloon at maturity. Annual interest payment from trust to grantor: $450,000.
• At year 9: Trust receives 9 years of 8% growth on $10 million minus $450,000/year of interest cash flow. Asset value inside trust grows to roughly $20 million. Trust pays the $10 million balloon, leaving roughly $10 million plus the seeded $1 million plus interest cash retained — call it $11–12 million of net wealth that has moved outside the estate.
• In the grantor's estate: The note has been retired. The estate contains the cumulative interest payments and the balloon payoff — assets the grantor still owns, taxed normally. But none of the $10 million of appreciation in excess of the AFR is in the estate.

At a 40% federal estate tax rate, that excess appreciation alone represents $4 million of avoided estate tax. Add the tax burn — the grantor paying, say, $300,000/year of trust income tax for nine years out of personal funds — and another roughly $1.1 million of additional wealth has moved to beneficiaries gift-tax-free.

The Rev. Rul. 2023-2 Trap

For decades, practitioners debated whether assets in a grantor trust qualified for a stepped-up basis under IRC §1014 when the grantor died. Some argued that because the grantor "owned" the trust for income tax purposes, the trust assets should be treated as owned by the grantor at death and receive a basis adjustment to fair market value — wiping out built-in capital gains.

In April 2023, the IRS slammed that door shut. Revenue Ruling 2023-2 flatly states: if the assets of an irrevocable grantor trust are not included in the grantor's gross estate, they do not receive a basis step-up at death. The trust takes the grantor's carryover basis, and beneficiaries who eventually sell will owe capital gains tax on every dollar of appreciation since the original purchase.

For IDGT planning, this means three things:

• Asset selection matters more than ever. Transfer high-basis assets — recently purchased real estate, newly-issued private stock, freshly-repurchased shares — into the IDGT. Keep low-basis legacy holdings inside the estate so they get the §1014 step-up at death.
• The "asset swap" technique becomes critical. Because the grantor retains the §675(4)(C) power of substitution, they can later swap appreciated trust assets for cash or high-basis personal assets of equal value. This pulls low-basis assets back into the estate (where they get a step-up) and pushes high-basis assets into the trust (where step-up is no longer needed). Done correctly, this captures the best of both regimes.
• Tracking basis is now non-negotiable. Beneficiaries of the trust will need detailed records of the grantor's original cost basis in every asset transferred. If those records are sloppy, the IRS will assume basis is zero and tax 100% of the eventual sale proceeds as gain.

IDGT vs. GRAT: Choosing the Right Estate Freeze

The IDGT installment sale is one of two dominant freeze techniques. The other is the Grantor Retained Annuity Trust (GRAT). Choosing between them is a function of mortality risk, liquidity, and asset character.

Practitioners frequently use both for the same client: GRATs for short-term, volatile, marketable security plays and IDGT sales for long-duration freezes of operating business interests where multi-generational planning (and GST allocation) is the goal.

Bookkeeping: The Boring Part That Saves the Strategy

Talk to any estate planning attorney who has defended an IDGT in audit and the same lament emerges: "The plan was fine. The records were a disaster."

The IRS does not need to attack the underlying tax theory to unwind an IDGT. It only needs to argue that the formalities were ignored — that interest payments were not actually made, that the trust commingled funds with the grantor, that the "loan" was really a retained interest under §2036(a)(1). Each of those arguments turns on documentation.

What proper bookkeeping for an IDGT actually requires:

• A separate bank account in the trust's name with its own EIN.
• A general ledger tracking every asset, liability, contribution, distribution, and intercompany transfer.
• Annual schedules showing the outstanding promissory note balance, accrued interest, and payment history.
• Cost basis records for every asset transferred in, swapped out, or distributed.
• Annual reconciliation between the trust's books and the grantor's personal books for amounts owed and tax payments made on the trust's behalf.

Plain-text accounting works extraordinarily well for trust administration precisely because every entry is auditable, version-controlled, and survives software vendor changes. A trust set up in 2026 may need to produce records in 2056 to settle a beneficiary dispute. A spreadsheet from 2026 in a defunct cloud product may be unreadable. A plain-text ledger checked into a Git repository will not be.

Common Mistakes That Sink IDGT Sales

Even sophisticated planners get burned. The same mistakes show up over and over:

1. Insufficient seed. A trust funded with $50,000 cannot credibly support a $10 million installment note. The IRS will recharacterize the entire arrangement as a retained interest, dragging the assets back into the estate.
2. Ignoring the AFR at the right month. AFRs are published monthly. Lock in the rate the month the sale closes, document it in the note, and never mix terms (a 5-year note must use the mid-term AFR, not the short-term rate).
3. No actual interest payments. "We'll catch up later" is the surest way to lose at audit. Pay the interest on time, every time, from the trust's bank account.
4. Stale appraisals. Discounted FLP/LLC interests need a defensible, contemporaneous valuation report. An appraisal done two years before the sale will not survive scrutiny.
5. Forgetting to switch off grantor status before death. When grantor status terminates (intentionally, or because the grantor dies), the trust becomes a separate taxpayer. If a substantial note is still outstanding, the deemed transfer can trigger gain recognition under the Madorin v. Commissioner line of cases. Many practitioners pay off or forgive the note before the grantor's expected death — but forgiveness is itself a gift, so timing matters.
6. Putting low-basis assets in the trust pre-Rev. Rul. 2023-2 thinking. If the strategy was set up before 2023 and never revisited, the asset mix may be exactly wrong for current law.

Who Should Actually Do This

IDGT sales are not for everyone. Realistically, the technique pays off when:

• Total estate value exceeds the lifetime exemption (or is expected to within the planning horizon, especially with the post-2025 sunset reducing the exemption).
• The grantor has assets that are likely to appreciate substantially faster than the AFR — operating businesses, concentrated equity positions, real estate in growth markets.
• The grantor has sufficient liquidity outside the trust to pay income tax on trust earnings comfortably for decades. The tax burn is a feature only if it does not crush the grantor's lifestyle.
• The grantor is comfortable making an irrevocable transfer. There is no take-back option.

If any of those conditions fails, simpler tools — annual exclusion gifts, 529 plans, life insurance trusts, charitable remainder trusts — usually deliver better risk-adjusted outcomes.

Keep Your Estate Plan's Records as Durable as the Plan Itself

An IDGT installment sale is a 30-to-50-year arrangement. The accounting records have to last just as long, survive multiple software platforms, and remain auditable by attorneys, accountants, and beneficiaries who may not exist yet. Beancount.io provides plain-text accounting that gives you complete transparency and version control over your trust and personal books — no proprietary database, no vendor lock-in, no risk that a discontinued cloud product takes your records with it. Get started for free and see why families and their advisors are switching to plain-text accounting for multi-generational planning.