If your business is worth $3 million today and you expect it to be worth $10 million in fifteen years, where does that extra $7 million of growth live for estate tax purposes? Under current law, if you do nothing, all of it sits inside your taxable estate, right alongside the $3 million you already have. A Spousal Lifetime Access Trust — a SLAT — is one of the few tools that can move that future growth out of your estate today, while still leaving your spouse with access to the money if you ever need it back.
For business owners whose net worth is concentrated in a single appreciating asset — a company, a real estate portfolio, a block of pre-IPO stock — that distinction between "value today" and "value at death" is where most of the estate tax exposure actually lives. This guide explains how a SLAT works, why the current exemption window makes 2026 a meaningful planning moment, and the mistakes that turn a good SLAT into an expensive one.
The problem a SLAT solves: growth you can't undo
Every taxpayer has a lifetime gift and estate tax exemption — the amount they can transfer, during life or at death, without triggering federal estate or gift tax. Thanks to the One Big Beautiful Bill Act, that exemption is set at $15 million per individual for 2026 ($30 million for a married couple), and it's now permanent with inflation adjustments starting in 2027, rather than reverting to a lower figure as prior law would have required.
That sounds like a lot of headroom. But the exemption shields the value of what you give away at the time you give it — not what it grows into. If you own a business that's compounding at 15–20% a year, the gap between "value at the time of a gift" and "value at your eventual death" can be enormous. A SLAT is designed to capture exactly that gap.
Here's the mechanic: one spouse (the "donor spouse") creates an irrevocable trust and funds it with assets — often a minority interest in the business, LLC units, or shares that are expected to appreciate substantially. The other spouse (the "beneficiary spouse") is named as a trust beneficiary, meaning they can receive distributions if the couple ever needs the money. Any future appreciation of those assets happens inside the trust, permanently outside both spouses' taxable estates. When the beneficiary spouse eventually dies, the remaining trust assets pass to the couple's children or other named beneficiaries — again, without being pulled back into either estate.
The donor spouse also typically keeps paying the income tax on the trust's earnings out of their own separate assets (a "grantor trust" structure). That's not a downside — it's a feature. Every dollar of tax the donor pays personally is effectively an additional tax-free gift to the trust, letting it compound faster than it otherwise would.
Why business owners specifically use this structure
A SLAT isn't a generic tax shelter — it's aimed at a specific situation: assets you don't need for daily living expenses, that are likely to appreciate meaningfully, and that you're comfortable permanently separating from your direct ownership. Business owners tend to check all three boxes at once.
You control the valuation moment. When you fund the SLAT, an independent appraisal sets the value of what's transferred — often a minority, non-controlling interest in the business, which can qualify for valuation discounts (for lack of control and lack of marketability) that reduce the amount charged against your exemption. Get the business into the trust at a conservative, well-supported valuation, and every dollar of growth above that number compounds tax-free from that point forward.
The couple keeps indirect access. Business owners are often reluctant to give away equity outright because they may need liquidity later — a bad year, an expansion that requires personal capital, an unexpected expense. Because the beneficiary spouse can receive distributions from the SLAT, the family isn't completely cut off from the wealth, even though it's outside the taxable estate. That's the core trade-off that makes SLATs more palatable than an outright gift to children.
Growth compounds where it can't be taxed again. A business interest that doubles or triples in value over 10–20 years builds all of that upside inside the trust. For a founder in the early-to-mid stages of growing a company, this is often where the majority of the estate tax savings comes from — not the initial transfer, but everything the transfer becomes.
The mechanics, step by step
- Draft the irrevocable trust. An estate planning attorney drafts the SLAT naming the beneficiary spouse (and often children or grandchildren as remainder beneficiaries), with specific terms for distributions, trustee powers, and how the trust winds down.
- Get an independent valuation. For a business interest, an outside appraiser values the specific interest being transferred — factoring in any applicable minority/marketability discounts. This valuation is the number that gets charged against the exemption, so it needs to be defensible; the IRS scrutinizes closely held business valuations more than almost anything else on a gift tax return.
- Fund the trust. The donor spouse transfers the interest into the trust. This is a completed gift, reported on IRS Form 709 (the federal gift tax return), and it uses up that portion of the donor's lifetime exemption.
- The trust operates, and grows. The trust may hold the business interest for years or decades. Distributions to the beneficiary spouse are possible under the terms of the trust, but they need to be genuinely discretionary and not a rubber-stamp "give it back whenever asked" arrangement, or the IRS may argue the transfer was never complete.
- Assets pass to the next generation, tax-free. When the beneficiary spouse dies (or per the trust's terms), the remaining assets — original value plus all the growth — pass to descendants without additional estate tax.
The mistake that undoes the whole structure: reciprocal trusts
The single most common SLAT mistake among business-owning couples is building two SLATs that mirror each other — one spouse creates a SLAT for the other, and vice versa, with the same assets, the same terms, funded around the same time. It's an intuitive instinct: "if one SLAT is good, two must be better, and it's only fair that we each get access."
That instinct runs straight into the reciprocal trust doctrine. If the IRS concludes that two trusts are functionally interchangeable — economically, each spouse is right back where they started, just with a different name on the paperwork — it can "uncross" the trusts and treat each spouse as the owner of the trust that was nominally created for them. That pulls both trusts back into both estates, defeating the entire purpose and potentially triggering penalties.
There's no statutory safe harbor that guarantees a pair of SLATs will survive this scrutiny. The practical approach estate planners use is to make the two trusts meaningfully different on multiple dimensions:
- Different funding times — spouse A funds their SLAT this year; spouse B funds theirs eighteen months to two years later, not the same week.
- Different beneficiaries or terms — one trust benefits the spouse and descendants; the other benefits descendants only, or uses a different distribution standard.
- Different trustees — avoid using the same trustee (or each other) across both trusts.
- Different assets and amounts — funding both trusts with identical business interests in identical proportions is exactly the pattern that draws scrutiny.
If you're a couple who both want SLAT-style planning, treat it as two separate, independently designed trusts — not a matched set.
Other risks worth planning around
Divorce. The beneficiary spouse's access to the trust is a function of the marriage. If the couple divorces, the donor spouse typically loses all indirect access to those assets — the trust's terms determine what happens, and not every SLAT accounts for this cleanly. Some trusts include a "floating spouse" provision or terminate the ex-spouse's beneficial interest on divorce; this needs to be decided explicitly at drafting, not left ambiguous.
Death of the beneficiary spouse. If the beneficiary spouse dies before the donor, the donor permanently loses indirect access to the trust assets — there's no way to reverse that. This is why advisors generally recommend only funding a SLAT with assets the family can genuinely live without.
Valuation scrutiny. Because SLATs are frequently used to transfer discounted business interests, the IRS pays close attention to how those discounts were calculated. A thin or unsupported appraisal is one of the most common reasons a gift tax return gets audited. Budget for a qualified, independent valuation — it's not the place to cut corners.
Is a SLAT the right move for your business?
SLATs make the most sense for owners who (1) have assets, income, or other business interests they don't need for living expenses, (2) expect meaningful appreciation in the assets being transferred, and (3) are comfortable with the asset being legally outside their direct control, even with indirect spousal access. If your business's future growth is genuinely uncertain, or your estate is well under the exemption threshold with little expectation of crossing it, the complexity and cost of a SLAT may not be worth it yet.
This is not a DIY project. A SLAT sits at the intersection of trust law, gift tax rules, and business valuation — it requires an estate planning attorney to draft the trust, a qualified appraiser to value what's transferred, and a CPA to handle the gift tax return and ongoing income tax treatment. Getting any one of those wrong can unwind the tax benefit entirely.
Keep the Underlying Numbers Clean
Whatever your estate plan ends up looking like, none of it works without an accurate, well-documented picture of what your business actually owns and what it's worth — the valuation an appraiser relies on is only as good as the books behind it. Beancount.io provides plain-text accounting that gives you a transparent, version-controlled record of your business's financial position, so when it's time to bring in an estate planning attorney or an appraiser, your numbers are already in order. Get started for free and keep your business's financial history as auditable as the rest of your plan.