Estate planning for high-net-worth couples is entering a period of major transition. With the federal estate and gift tax exemption scheduled to drop by roughly half on January 1, 2026, many families are re-evaluating strategies to reduce future tax exposure while maintaining financial flexibility. One tool gaining renewed attention is the Spousal Lifetime Access Trust (SLAT)—an irrevocable trust that allows one spouse to transfer assets out of their taxable estate while still preserving indirect access to those assets through the other spouse.
A SLAT can be a powerful planning strategy, but it’s not a simple one. It comes with important tax considerations, risks, and structuring requirements. Understanding how these trusts work is essential before deciding whether they belong in your estate plan.
Below, we break down how SLATs function, why they’re increasingly relevant ahead of 2026, and what pitfalls to avoid if you’re considering one.
Table of Contents
- What is a spousal lifetime access trust?
- How a SLAT works
- Why high-net-worth couples use SLATs
- Key risks and mistakes to avoid
- When a SLAT may be a good fit
- How Harness tax advisors help with SLAT planning
What is a spousal lifetime access trust?
A Spousal Lifetime Access Trust (SLAT) is an irrevocable trust that allows one spouse (the donor spouse) to make a lifetime gift of assets for the benefit of the other spouse (the beneficiary spouse) and, in many cases, future generations. Once assets are transferred into the trust, they are removed from the donor’s taxable estate, and any future growth occurs outside the estate as well.
What makes a SLAT unique is that although the donor gives up direct control over the assets, the couple may still maintain indirect access through the beneficiary spouse. The beneficiary spouse can receive distributions under the trust’s terms, which can help support the household while the trust continues to grow outside the taxable estate.
SLATs have always been a valuable estate planning tool, but interest has accelerated as the federal estate and gift tax exemption is scheduled to drop significantly in 2026. Many high-net-worth couples are exploring ways to use the current higher exemption before it sunsets.
How a SLAT works
Before getting into the details, it’s helpful to look at how assets move into the trust and how each spouse interacts with it once created.
Funding the trust
The donor spouse creates and funds the SLAT using individually owned assets—assets owned jointly or as community property generally cannot be transferred without additional planning. Funding the trust is treated as a taxable gift, but the donor can apply part of their lifetime gift and estate tax exemption to reduce or eliminate gift tax. In many cases, the donor will need to file IRS Form 709 to report the transfer.
How distributions work
Even though the trust is irrevocable, the beneficiary spouse can request distributions for purposes such as health, education, maintenance, or support (often referred to as the HEMS standard). These distributions keep the trust’s tax benefits intact while still allowing the couple to benefit from the assets if needed.
What happens at the beneficiary spouse’s death
When the beneficiary spouse dies, the remaining trust assets typically pass to children, grandchildren, or other designated beneficiaries. These transfers may occur outright or through additional trusts, but either way, the assets generally avoid estate tax because they were removed from the taxable estate when the SLAT was originally funded.
Why high-net-worth couples use SLATs
Before exploring specific benefits, it’s important to understand why SLATs have become a focal point in modern estate planning. For many couples, these trusts offer a way to manage significant wealth transfers while preserving flexibility—something not always possible with other irrevocable trust structures.
Estate tax reduction
One of the primary reasons couples use SLATs is to reduce potential federal estate taxes. When the donor spouse transfers assets into the trust, those assets—and any future appreciation—are removed from the donor’s taxable estate. This can help preserve more wealth for future generations, especially for families expecting their estates to exceed the reduced exemption starting in 2026.
Removing future appreciation from the estate
Even if a couple’s current net worth is below the estate tax threshold, future growth can push them into taxable territory. A SLAT allows appreciating assets (such as business interests, real estate, or investment portfolios) to grow outside the estate, which can significantly reduce long-term tax exposure.
Maintaining indirect access to assets
Unlike many irrevocable trusts, a SLAT allows the couple to retain indirect access to funds through the beneficiary spouse. If the beneficiary spouse requests a distribution within the trust’s guidelines, the household may benefit while the trust structure continues to protect estate tax efficiency. This balance of access and asset protection is a key reason SLATs appeal to families who want tax advantages without feeling overcommitted or financially restricted.
Considering a SLAT but unsure whether it fits your long-term goals? Harness advisors specialize in estate and tax planning for complex households, including strategies involving trusts, equity, and privately held assets. We help you evaluate whether a SLAT makes sense for your situation and how it fits into your broader wealth strategy.
Key risks and mistakes to avoid
Before setting up a SLAT, it’s important to understand the potential pitfalls that can affect the trust’s long-term success. While SLATs can be highly effective, they require careful planning and ongoing coordination to avoid tax or legal issues. Keeping the following risks in mind can help ensure the trust functions as intended.
Divorce or premature death
A SLAT’s benefits rely on the marriage remaining intact. If the couple divorces or the beneficiary spouse dies, the donor spouse loses indirect access to the trust assets. For couples using SLATs as part of long-term planning, it’s essential to consider the stability of the marital relationship and the beneficiary spouse’s life expectancy.
Choosing the right trustee
The beneficiary spouse can serve as trustee, but their discretion must be limited to the HEMS standard—health, education, maintenance, or support. If the beneficiary spouse has broader authority, the IRS may argue the trust assets should be included in their taxable estate. To avoid this, many couples appoint an independent co-trustee or use a corporate trustee.
Avoiding the reciprocal trust doctrine
Some couples want to create SLATs for each other, but this can trigger the “reciprocal trust doctrine” if the two trusts are too similar. If the IRS determines the trusts mirror each other, they may unwind the structure and treat each spouse as though they retained control. To reduce this risk, advisors typically vary the trust terms, timing, beneficiaries, or funding sources.
Gift tax considerations
Funding a SLAT uses part of the donor spouse’s lifetime gift and estate tax exemption. Overfunding the trust—or misunderstanding how gifts are split—may create unexpected gift tax liability. In many cases, the donor must file IRS Form 709 to report the gift.
Funding with the right assets
The type of assets placed in the SLAT can affect both tax efficiency and long-term performance. Appreciating assets typically provides the greatest estate tax benefit. However, the donor generally cannot transfer assets held jointly with the spouse or as community property without additional steps, which may complicate planning.
No step-up in basis
Assets transferred into a SLAT do not receive a step-up in basis at the donor spouse’s death. Beneficiaries who later sell those assets may owe higher capital gains taxes. This tradeoff between estate tax reduction and potential capital gains exposure should be evaluated carefully.
When a SLAT may be a good fit
Before deciding whether to create a SLAT, it’s helpful to understand the situations where this type of trust aligns well with a family’s goals. While no single strategy works for everyone, SLATs tend to be most effective for couples with substantial assets, long-term planning objectives, and a desire for both tax efficiency and financial flexibility.
Couples expecting to exceed the future estate tax exemption
With the federal estate and gift tax exemption scheduled to drop in 2026, many families who are currently under the threshold may find themselves in taxable territory. A SLAT allows couples to use today’s higher exemption before it potentially shrinks, removing significant assets—and future appreciation—from their estates.
Families who want to preserve long-term control and protection
For families who want to pass wealth to future generations while also creating guardrails, SLATs can offer more protection than outright gifts. Assets held in the trust can be shielded from creditors, divorce settlements, and financial mismanagement, depending on how the trust is structured.
How Harness tax advisors help with SLAT planning
Estate planning is rarely a one-decision moment—it’s an ongoing process that touches taxes, investments, family dynamics, and long-term goals all at once. That kind of coordination is exactly where having the right team makes the biggest difference.
Harness connects you with a curated network of vetted financial and tax advisors who specialize in serving high-net-worth households, founders, and equity-compensated professionals. Beyond evaluating individual strategies like SLATs, your advisor looks at your full financial picture—coordinating estate planning with tax projections, investment management, charitable giving, and the major life decisions that shape generational wealth. As tax laws and your circumstances evolve, your plan can evolve with them.
If you’re thinking through a SLAT or any other complex planning strategy, the most valuable next step is getting matched with an expert who knows the terrain.
Get started with a Harness Tax Advisor
Meet the Authors
David Snider
David Snider is the Founder & CEO of Harness, a platform to power entrepreneurial tax advisors & their clients. Harness was recognized by Inc Magazine as one of the 200 fastest growing companies in the U.S. David incubated Harness as an executive-in-residence at Bain Capital Ventures. Previously he served as COO & CFO of Compass, a real estate tech company that he helped grow from pre-launch to a valuation of $1.8 billion. David was an investor at Bain Capital private equity, where he completed investments worth over $2 billion as well as the IPO of Sensata on the NYSE. He is the author of Money Makers, published by Macmillan.
Disclaimer:
Tax related products and services provided through Harness Tax LLC. Harness Tax LLC is affiliated with Harness Wealth Advisers LLC, collectively referred to as “Harness Wealth”. Harness Wealth Advisers LLC is a paid promoter, internet registered investment adviser. Registration does not imply a certain level of skill or training. This article should not be considered tax or legal advice and is provided for informational purposes only. Please consult a tax and/or legal professional for advice specific to your individual circumstances. This article is a product of Harness Tax LLC.
Content was prepared by a third-party provider and not the adviser. Content should not be regarded as a complete analysis of the subjects discussed. Although we believe the content is reliable, it is not guaranteed as to accuracy and does not purport to be complete nor is it intended to be the primary basis for financial or tax decisions.
This blog contains links to other web sites as a convenience to the reader. These include links to web sites operated by one or more of the following: government agencies, nonprofit organizations and/or private businesses. When you use any of these links, you are no longer viewing our material, and our Privacy Notice will not apply. When you link to another web site, you are subject to the privacy policy of that new site. When you follow a link to one of these sites neither Harness, nor any agent, officer, or employee of Harness warrants the accuracy, reliability or timeliness of any information published by these external sites, nor endorses any content, viewpoints, products, or services linked from these systems, and cannot be held liable for any losses caused by reliance on the accuracy, reliability or timeliness of their information. Portions of such information may be incorrect or not current. Any person or entity that relies on any information obtained from those web sites does so at her or his own risk.