A marital trust is revocable while both spouses are alive and becomes irrevocable the moment the first spouse dies. That shift answers the question of whether a marital trust is revocable or irrevocable: it is both, at different stages. The change is not a flaw in the design. It is the mechanism that lets the trust qualify for the federal marital deduction, which defers estate tax until the surviving spouse’s death.
While Both Spouses Are Alive
During the couple’s joint lifetime, a marital trust usually sits inside a revocable living trust. Either spouse can amend the terms, add or remove assets, change beneficiaries, or dissolve the trust entirely. Many couples use an A-B structure where everything stays in a single pool until the first death. No estate tax deduction has been claimed yet, so federal law has no reason to lock anything down.
For income tax purposes, a revocable trust is essentially invisible. The couple keeps reporting income on their personal returns using their existing Social Security numbers, and no separate trust return is required.
What Changes When the First Spouse Dies
At the first death, the trust splits. The portion set aside for the surviving spouse, often called the A Trust or marital trust, converts to irrevocable. The surviving spouse cannot rewrite or dissolve that portion. Whatever terms the deceased spouse put in place become permanent, which is what protects the distribution plan for children, grandchildren, or other final beneficiaries.
This conversion is what qualifies the trust for the federal marital deduction. A decedent can pass an unlimited amount of property to a surviving spouse free of estate tax, but only if the transfer meets specific requirements, and for trust-based transfers one of those is that the arrangement cannot be undone after death.1Office of the Law Revision Counsel. 26 USC 2056 – Bequests, Etc., to Surviving Spouse The deduction postpones the estate tax bill until the surviving spouse dies, at which point the remaining trust assets fall into the survivor’s taxable estate.
For 2026, the federal estate tax exemption is $15,000,000 per person, or $30,000,000 for a married couple, following the permanent increase enacted by the One Big Beautiful Bill Act.2Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026 Estates above that threshold are taxed at a top rate of 40%.3Office of the Law Revision Counsel. 26 USC 2001 – Imposition and Rate of Tax The marital deduction lets the first estate avoid that tax entirely by passing qualifying property to the survivor, but it does not erase the tax, it only moves it to the second death.
Steps the Trustee Must Take Once the Trust Is Irrevocable
Several administrative tasks need to happen quickly after conversion. The IRS requires the now-irrevocable trust to obtain its own Employer Identification Number, because it can no longer use the deceased grantor’s Social Security number for tax reporting.4Internal Revenue Service. When to Get a New EIN You can apply online at IRS.gov and typically receive the number the same day.
The trustee or personal representative should also file Form 56 to notify the IRS that a fiduciary is now managing the trust.5Internal Revenue Service. Survivors, Executors, and Administrators From that point forward, the irrevocable trust files its own annual income tax return on Form 1041. Most states also require the trustee to notify beneficiaries within a set window after the trust becomes irrevocable, typically 30 to 60 days, though the exact deadline varies by state.
How Much Control the Surviving Spouse Keeps
Irrevocable does not mean the same thing in every marital trust. The two forms that qualify for the marital deduction give the surviving spouse very different levels of access.
QTIP Trusts
A Qualified Terminable Interest Property trust is the most common form. Federal law requires that the surviving spouse receive all income the trust produces, paid at least annually, and that no one other than the surviving spouse receive distributions during the survivor’s lifetime.1Office of the Law Revision Counsel. 26 USC 2056 – Bequests, Etc., to Surviving Spouse The executor activates QTIP treatment by making an election on Schedule M of IRS Form 706, and that election is irrevocable once filed.6Internal Revenue Service. Instructions for Form 706
The trade-off for the tax benefit is control after death. The surviving spouse does not decide where the trust assets go when they die. The deceased spouse’s trust document names the final beneficiaries, often children from a prior marriage, which is why QTIPs are common in blended families.
Access to the trust principal depends on the document. Many QTIP trusts let the trustee distribute principal for the surviving spouse’s health, education, maintenance, or support, a standard known as HEMS. Others restrict the spouse to income only. The language of the specific trust controls.
General Power of Appointment Trusts
A general power of appointment trust also requires annual income distributions and is irrevocable after the first death, but the surviving spouse holds a general power of appointment, meaning the legal authority to direct the trust assets to anyone, including themselves, their estate, or their creditors.7Office of the Law Revision Counsel. 26 USC 2056 – Bequests, Etc., to Surviving Spouse – Section (b)(5) In practice, the surviving spouse can withdraw principal, redirect assets to new beneficiaries, or spend the trust down entirely. The trust still exists as a separate legal entity for tax purposes, so the “irrevocable” label is real, but it does not restrict the survivor the way a QTIP does.
One consequence of that broader power: because the surviving spouse can exercise it in favor of their own creditors, trust assets may be reachable by those creditors under state law.8eCFR. 26 CFR 20.2041-1 – Powers of Appointment; In General A QTIP generally provides stronger creditor protection, and couples worried about lawsuits or claims often prefer that structure for the same reason.
What Happens at the Second Death
The marital deduction defers estate tax, it does not eliminate it. When the surviving spouse dies, the full value of the marital trust is included in their gross estate, whether the trust is a QTIP or a GPA.9Office of the Law Revision Counsel. 26 USC 2044 – Certain Property for Which Marital Deduction Was Previously Allowed If the survivor’s own assets plus the trust exceed the federal exemption, the excess is taxed at rates up to 40%.
For a QTIP, the trust document controls where the assets go next, usually to the first spouse’s chosen beneficiaries. For a GPA trust, the surviving spouse may have already redirected the assets using their power of appointment. If they did not exercise it, the trust’s default beneficiaries take what remains.
One Boundary: Non-Citizen Surviving Spouses
The unlimited marital deduction does not apply when the surviving spouse is not a U.S. citizen. To defer estate tax in that situation, the assets must pass into a Qualified Domestic Trust (QDOT) with at least one trustee who is a U.S. citizen or a domestic corporation, and that trustee must have the right to withhold estate tax from any principal distribution.10Office of the Law Revision Counsel. 26 USC 2056A – Qualified Domestic Trust Unlike a standard marital trust, a QDOT triggers estate tax on every lifetime principal distribution to the surviving spouse, not just at the second death. If the surviving spouse becomes a U.S. citizen before the estate tax return deadline, the QDOT requirement may be waived.