A survivor’s trust is the revocable portion of a married couple’s joint living trust that holds the surviving spouse’s share of the assets after the first spouse dies. It stays fully under the surviving spouse’s control, meaning they can spend, sell, reinvest, or redirect those assets however they want. The survivor’s trust is one half of what estate planners call an “AB trust” structure, where a single joint trust divides into two sub-trusts the moment the first spouse passes away.
How the Joint Trust Splits at the First Death
While both spouses are alive, their joint revocable living trust works as one entity. Either spouse can add assets, pull them out, or change the terms. When the first spouse dies, the trust document triggers a split into two sub-trusts, usually labeled Trust A and Trust B.
Trust A is the survivor’s trust. It holds the surviving spouse’s own share of the couple’s property and remains revocable. Trust B goes by several names: bypass trust, credit shelter trust, or decedent’s trust. It holds the deceased spouse’s share and becomes irrevocable the moment it comes into existence. The surviving spouse cannot rewrite Trust B, dissolve it, or change its beneficiaries.
Not every joint trust uses this two-trust split. Some couples, especially those with estates well below the federal estate tax threshold, choose simpler arrangements where everything passes directly to the surviving spouse. The AB structure remains the standard framework for couples who want to preserve tax benefits, protect assets for children from a prior marriage, or control how the deceased spouse’s wealth is eventually distributed.
What Goes Into the Survivor’s Trust
The survivor’s trust typically receives the surviving spouse’s half of community property or their separate property, plus any portion of the deceased spouse’s assets that the trust document directs to the survivor outright. The specific allocation depends on how the document was drafted and what the couple wanted.
Splitting assets between the two sub-trusts is one of the most important administrative steps after the first death, and the method matters for taxes. The two common approaches are pecuniary funding, which assigns a fixed dollar amount to one trust with the remainder going to the other, and fractional funding, which assigns each trust a percentage of the total estate. Fractional funding tends to be more tax-efficient because both trusts share proportionally in any gains or losses between the date of death and the date of distribution. Pecuniary funding can trigger capital gains tax on appreciated assets, because transferring them to satisfy a fixed-dollar amount is treated as a sale.
The trust document controls which method applies. Couples whose trust was drafted years ago should check this provision, because the wrong funding method can create an unexpected tax bill at the worst possible moment.
What the Surviving Spouse Can Do With It
The surviving spouse usually serves as trustee of the survivor’s trust and has broad authority over its contents. Because the trust remains revocable, the surviving spouse can sell property, reinvest proceeds, withdraw cash, and use trust funds for any purpose. Income earned by the trust’s assets flows through to the surviving spouse’s personal tax return, and no separate tax identification number is needed.
The surviving spouse can also rewrite the terms. That includes changing who inherits, adjusting distribution percentages, adding or removing beneficiaries, and dissolving the trust entirely to take the assets outright. This flexibility is one of the main things that sets the survivor’s trust apart from the bypass trust, where the terms are locked in.
Powers of Appointment
Some trust documents also give the surviving spouse a “power of appointment” over bypass trust assets, meaning legal authority to redirect who receives trust property. A general power of appointment is the broadest, allowing the surviving spouse to appoint assets to anyone, including themselves or their own estate. A limited power of appointment restricts the surviving spouse to a defined group, such as the couple’s descendants.
The type of power matters for taxes. A general power of appointment causes the affected assets to be included in the surviving spouse’s taxable estate. A limited power does not. For many families, a limited power over the bypass trust strikes the right balance: the surviving spouse gets some say in distribution without pulling those assets back into their own estate.
How It Differs From the Bypass Trust
The bypass trust holds the deceased spouse’s share of assets, up to the federal estate tax exemption amount. It becomes irrevocable at the first spouse’s death. The surviving spouse may be a beneficiary of the bypass trust and can receive income from it, but access to the principal is usually limited to distributions for health, education, maintenance, or support, a standard estate planners abbreviate as “HEMS.”
The core purpose of the bypass trust is in the name: its assets bypass the surviving spouse’s taxable estate. When the surviving spouse eventually dies, bypass trust assets pass directly to the named beneficiaries, usually the couple’s children, without being counted as part of the surviving spouse’s estate. For large estates, this can shield millions from estate tax.
The trade-off is rigidity. The surviving spouse cannot change beneficiaries, cannot dissolve the trust, and faces real restrictions on withdrawals. The trustee must also keep separate records for the bypass trust and file an annual fiduciary income tax return on Form 1041, which adds ongoing administrative cost. None of that applies to the survivor’s trust.
Estate Tax, Portability, and the Step-Up in Basis
The federal estate tax exemption for 2026 is $15 million per individual, or $30 million for a married couple.1Office of the Law Revision Counsel. 26 U.S. Code 2010 – Unified Credit Against Estate Tax Estates below that threshold owe no federal estate tax, so most families will never face a federal estate tax bill. Families with significant wealth or appreciating assets still need to plan carefully.
Portability lets a surviving spouse claim the deceased spouse’s unused estate tax exemption on top of their own. If the first spouse to die used none of their $15 million exemption, the surviving spouse could potentially shelter up to $30 million. Portability is not automatic. The executor of the deceased spouse’s estate must file IRS Form 706 within nine months of the death (with a possible six-month extension), even if the estate owes no tax at all.2Internal Revenue Service. Instructions for Form 706 Miss that deadline and the unused exemption is gone for good. This is one of the most commonly overlooked steps in trust administration, and it can cost a family millions.
Portability has reduced the urgency of bypass trust planning for many couples. If both spouses’ exemptions can simply be stacked, there’s less reason to lock assets in an irrevocable trust just to preserve the first exemption. Bypass trusts still serve purposes beyond federal estate tax. They shield assets from the surviving spouse’s creditors, protect inheritances if the surviving spouse remarries, and in the roughly dozen states that impose their own estate tax with lower exemption thresholds, they can shelter assets at the state level where portability does not apply.
There’s also the step-up in basis to consider. When someone dies, assets in their taxable estate generally receive a step-up in cost basis to fair market value at the date of death. Assets in the survivor’s trust will get a step-up when the surviving spouse dies, because those assets are part of their taxable estate. Assets in the bypass trust generally do not get a second step-up, because the whole point of the bypass trust is to exclude its contents from that estate. If bypass trust assets have appreciated significantly between the two deaths, the beneficiaries can face a larger capital gains bill when they sell. For families whose total estate falls well within the combined exemption, keeping everything in the survivor’s trust can produce a better tax outcome than the AB split, because the second step-up eliminates capital gains that would exceed any estate tax saved.
Administrative Steps After the First Spouse Dies
Splitting the joint trust is not just a legal formality. It requires concrete action, and delays can cause problems.
- Every asset in the joint trust must be valued as of the date the first spouse died. That means real estate appraisals, account statements, and valuations of any business interests. These numbers drive the allocation between the two sub-trusts.
- Assets must be retitled. A brokerage account held by “John and Jane Smith, Trustees of the Smith Family Trust” now needs to be split, with some holdings titled under Trust A and others under Trust B.
- The bypass trust needs its own Employer Identification Number from the IRS, because it is a separate taxpaying entity. The survivor’s trust continues using the surviving spouse’s Social Security number.
- Form 706 must be filed within nine months of the first death if the family wants to preserve portability, even when no estate tax is owed.2Internal Revenue Service. Instructions for Form 706
- The bypass trust must file Form 1041 every year for as long as it exists. The survivor’s trust has no separate filing requirement.
What Happens When the Surviving Spouse Dies
At the surviving spouse’s death, the survivor’s trust becomes irrevocable and its remaining assets go to the final beneficiaries named in the document, typically the couple’s children or other heirs. Because the survivor’s trust assets were part of the surviving spouse’s taxable estate, they receive a step-up in basis to fair market value, which can significantly reduce the capital gains the beneficiaries would otherwise pay on sale.
The bypass trust distributes its assets at this point too, but those assets have been outside the surviving spouse’s estate all along. The beneficiaries receive them without additional estate tax, though they take the assets at the stepped-up basis from the first spouse’s death rather than a refreshed one.
Both trusts distribute outside of probate, so the beneficiaries avoid the delays, legal fees, and public disclosure that come with court-supervised administration. The trust document controls everything, and a successor trustee named in the document handles the actual distributions. For most families, this wraps up in weeks or months rather than the year or more probate can take.