What Is the Marital Deduction?

The marital deduction is a key provision in U.S. tax law that allows spouses to transfer unlimited amounts of assets to each other during life or at death without incurring federal estate or gift taxes. Established under the Internal Revenue Code, the marital deduction is an essential component of estate and gift tax planning for married couples. It helps delay taxation on assets transferred between spouses, providing flexibility in how wealth is passed on and often helping to preserve family estates across generations.

Legal Basis and Purpose

The marital deduction was introduced in 1948 to equalize the tax treatment of married couples and to recognize the economic unit formed by marriage. It is primarily governed by Internal Revenue Code (IRC) § 2056 for estate tax purposes and IRC § 2523 for gift tax purposes.

The central idea is that transfers between spouses should not be taxed while both are living or upon the first spouse’s death, because the surviving spouse is still part of the same economic unit. Taxation is deferred until the surviving spouse either makes gifts to someone else or passes away, at which point estate or gift taxes may apply unless other exemptions are available.

Requirements for the Marital Deduction

To qualify for the marital deduction, several criteria must be met:

• Legal marriage: The spouses must be legally married under federal law. This includes same-sex marriages recognized by the U.S. government.
• Citizenship: The recipient spouse must be a U.S. citizen to receive the unlimited deduction. If the spouse is not a U.S. citizen, special rules apply (see below).
• Outright transfer or qualifying trust: The transferred property must go directly to the spouse or into a specially designed trust that qualifies for the deduction, such as a Qualified Terminable Interest Property (QTIP) trust.
• No terminable interest: In general, the deduction does not apply if the surviving spouse’s interest in the property ends upon a specific event, such as remarriage or a certain number of years passing. However, this rule has exceptions, most notably for QTIP trusts.

Marital Deduction and Estate Planning

In estate planning, the marital deduction is often used in combination with the federal estate tax exemption, which allows a certain amount of wealth to pass tax-free to non-spouse beneficiaries. In 2025, for example, the exemption is $13.99 million per individual. If a person leaves everything to their spouse, the entire estate qualifies for the marital deduction, and no estate tax is due at the first spouse’s death. However, this can lead to missed opportunities to use the exemption at the first death, which is why many estate plans incorporate credit shelter trusts to make use of both spouses' exemptions while still preserving the marital deduction.

Proper use of the marital deduction can effectively double the amount a married couple can transfer tax-free to heirs by combining their exemptions. This is known as portability, where the unused portion of the first spouse’s exemption can be transferred to the surviving spouse.

Non-Citizen Spouse Rules

If the recipient spouse is not a U.S. citizen, the unlimited marital deduction is not available, even if they are a permanent resident. This restriction exists because the IRS cannot ensure it will eventually collect estate taxes when the non-citizen spouse dies, especially if they relocate outside the U.S.

To address this, a Qualified Domestic Trust (QDOT) can be established. A QDOT allows the estate of the deceased U.S. citizen spouse to claim the marital deduction while placing restrictions on the distribution of assets to the non-citizen spouse. The trustee of the QDOT must be a U.S. citizen or U.S. bank, and certain rules must be followed to ensure eventual estate tax compliance.

Qualified Terminable Interest Property (QTIP) Trusts

A QTIP trust is often used when the first spouse wants to provide income or support to the surviving spouse while preserving control over how the remaining assets are distributed after the second spouse dies. This is particularly common in blended families or second marriages.

A QTIP trust qualifies for the marital deduction even though the surviving spouse does not receive full ownership of the assets. The trust must provide all income to the surviving spouse for life, and no other person can access the principal during that time. Upon the surviving spouse’s death, the trust assets are included in their estate for tax purposes.

Limitations and Considerations

While the marital deduction defers estate and gift tax liability, it does not eliminate it entirely. The second spouse’s estate may be significantly larger, and without proper planning, the deferred taxes could become substantial. Additionally, using the marital deduction without coordinating with other estate planning strategies can lead to inefficiencies, particularly for couples with taxable estates.

It’s also important to note that the deduction only applies to transfers that meet strict criteria. Improper titling of assets, vague trust language, or failure to comply with QDOT or QTIP requirements can disqualify a transfer, leading to unintended tax consequences.

The Bottom Line

The marital deduction is a powerful tool in estate and gift tax planning, allowing married couples to transfer assets between themselves without immediate tax consequences. While it offers flexibility and defers taxation until the second spouse's death, it should be used thoughtfully, in coordination with other estate planning strategies. Understanding its requirements — particularly when it involves non-citizen spouses or trusts — is essential to preserving wealth and achieving long-term planning goals.