How to Address Inheritance in a Prenup (2026 Guide)

How do you address inheritance in a prenuptial agreement?

A prenup lets you and your partner define inherited assets as separate property in a written, enforceable contract, so state defaults and everyday financial decisions can't quietly erode that classification over years of marriage. Instead of relying on a legal presumption that may not survive a joint bank deposit or a home renovation, you put your shared intentions on paper.

The core of addressing inheritance in a prenup involves three things:

1. Identifying inherited assets by name, account, or description so they're designated as separate property from day one.
2. Setting usage rules that spell out how inherited funds can and cannot be mixed with marital finances.
3. Defining appreciation and income treatment so growth on inherited investments, real estate, or businesses follows a path you both agreed to.

This matters right now. Cerulli Associates' 2024 wealth-transfer projections estimate that $124 trillion in assets will transfer between generations by 2048. For many engaged couples, inheritance isn't a hypothetical. It's a planning conversation that belongs alongside budgets, housing, and career goals.

As Michael C. Cotugno, Esq., Managing Partner, Neptune Legal, puts it: "For conscious partners, wealth is not merely a collection of assets; it's a powerful tool with the potential for profound purpose."

Framing inheritance terms in a prenup is an act of alignment. You're deciding together how family wealth fits into your shared life, not hiding it.

Is inheritance automatically separate property when you marry?

Yes, in nearly every U.S. state, inheritance received before or during marriage is treated as the recipient's separate property by default. That classification is favorable, but it's also fragile.

In community property states like California, Family Code §770 explicitly classifies property acquired during marriage by gift, bequest, devise, or descent as the receiving spouse's separate property. In equitable distribution states like New York, inheritance falls under the separate property category as long as the recipient keeps it distinct from marital assets.

Here's the distinction that matters:

The default classification works in your favor, but it depends entirely on what you do with the inherited asset after you receive it. One financial decision, like depositing inherited funds into a shared checking account, can start the process of reclassification. A prenup reinforces the default by putting the classification in writing and adding rules that prevent accidental erosion. You're not overriding state law so much as building a stronger version of it.

How does commingling turn inherited assets into marital property?

Commingling happens when you mix inherited assets with marital property in ways that make it difficult (or impossible) for a court to tell them apart. Once that line blurs, a judge may treat some or all of the inherited asset as marital property subject to division.

The most common commingling triggers include:

• Depositing inherited money into a joint bank account used for everyday expenses
• Using inheritance funds to buy jointly titled property, like a home in both names
• Paying for renovations on a shared home with inherited money
• Retitling inherited property to include your spouse's name
• Mixing inherited funds with marital funds so thoroughly that the original inheritance can't be traced

Commingling doesn't require intent. You don't have to mean to convert separate property into marital property for it to happen. A well-meaning decision to combine finances "because we're married now" is often enough.

A prenup addresses this by setting agreed-upon rules for how inherited funds can and cannot be used. For example, a clause might state that depositing inherited money into a joint account for a specific, documented purpose (like a down payment) does not convert the underlying inheritance into marital property. Or it might require that inherited funds always remain in a separately titled account. These terms create a paper trail and a legal framework that survive the messiness of daily financial life.

Without a prenup, the burden of tracing inherited funds through years of joint transactions falls on the inheriting spouse, and that burden is both expensive and uncertain. New York's equitable distribution framework, for instance, places the responsibility of proving separate property status squarely on the spouse claiming it.

What can a prenup say about inherited appreciation and future inheritances?

A prenup can specify that both passive market-driven growth and active appreciation on inherited assets remain separate property. It can also cover inheritances you haven't received yet, including trust distributions, family business interests, and anticipated bequests.

Passive vs. active appreciation

This distinction drives more litigation than almost any other inheritance issue:

• Passive appreciation is growth driven by market forces or factors outside the marriage. An inherited stock portfolio that rises with the S&P 500 is a classic example. This generally stays separate property even without a prenup.
• Active appreciation is growth caused by either spouse's effort or the investment of marital funds. If you inherit a rental property and your spouse manages it, renovates units, and increases rental income, the resulting value increase may be classified as marital property.

Without a prenup, the active appreciation question invites expensive litigation about exactly how much growth came from market forces versus a spouse's effort. A prenup can assign all appreciation (passive and active) to the inheriting partner, or it can split active appreciation by a formula you both agree to. Either way, the terms are settled before emotions run high.

Future inheritances

You don't have to wait for an inheritance to arrive before addressing it. A prenup can include clauses covering:

• Anticipated inheritances from parents, grandparents, or other family members
• Trust distributions you're already named as a beneficiary of, or expect to be
• Family business interests that may transfer during the marriage
• Income generated from inherited assets, such as dividends, rent, or business profits

For couples whose families use trusts for estate planning, coordinating the prenup language with the trust terms is important. An experienced attorney can draft clauses that align with existing trust structures so the prenup doesn't accidentally contradict or weaken the trust's intent. If your family hasn't finalized their estate documents, this is a good moment to coordinate. Neptune's prenup and estate planning approach pairs couples with attorneys who handle both.

What a prenup can and cannot do for inherited assets

A prenup can waive a surviving spouse's statutory right to claim a share of the estate (known as the "elective share" in most states), but it cannot waive federal survivor benefits on 401(k)s and pensions. That's a limitation many couples miss.

Coverage comparison

The ERISA limitation is significant. Under federal law, your spouse has an automatic right to survivor benefits on qualified retirement plans. A prenup signed before marriage can't waive that right because your partner isn't yet a "spouse" under ERISA at the time of signing. The workaround is a spousal waiver signed after the wedding, which the plan administrator typically provides. Your attorney and financial planner should flag this during the prenup process so it doesn't fall through the cracks.

Blended families and second marriages

For couples entering a second marriage, or where one or both partners have children from a prior relationship, these overlapping tools become even more important. Without a prenup and coordinated estate documents, a surviving spouse may have a legal claim to assets you intended for your children. In most states, a surviving spouse can claim an elective share (often one-third to one-half of the estate) regardless of what the will says. A prenup that waives this right, paired with a trust directing assets to your children, creates the alignment many blended families need.

A framework for planning inheritance terms with your partner

Building inheritance terms into a prenup works best as a structured, collaborative process. Here's a step-by-step framework:

Step 1: Inventory inherited and expected assets

Make a list of every inherited asset you've already received and every inheritance you reasonably expect. Include bank accounts, investment portfolios, real estate, trust interests, family business stakes, and personal property like heirlooms. Be specific: account numbers, property addresses, approximate values with dates.

Step 2: Decide on usage rules together

Talk through scenarios. Can inherited money be used for a down payment on a shared home? If so, does the inheriting partner retain a dollar-for-dollar claim, or does it become a gift to the marriage? What about using inherited funds for a child's education? These conversations are the substance of a prenup, not legal technicalities.

Step 3: Address appreciation and income

Decide how passive and active appreciation will be treated. If one partner inherits a family business and the other contributes to running it, how will that growth be handled? Will income from inherited investments (dividends, rent, interest) stay separate or become marital? There's no single right answer. The right answer is the one you both agree to.

Step 4: Coordinate with estate planning documents

A prenup that addresses inheritance should align with wills, trusts, and beneficiary designations. If your prenup waives the elective share but your will doesn't account for that waiver, there's a gap. If your parents' trust distributes assets to you but the prenup doesn't reference trust distributions, there's another gap. Working with an attorney who handles both prenups and estate planning closes these gaps.

Step 5: Ensure enforceability

For a prenup addressing inheritance to hold up in court, it generally must be:

• In writing and signed by both partners
• Entered voluntarily, without coercion or undue pressure
• Supported by full financial disclosure from both sides
• Fair and reasonable at the time of signing (and in some states, at the time of enforcement)

Independent counsel for each partner is highly recommended for an enforceable prenup. Courts look much more favorably on agreements where both parties had their own attorney review and explain the terms.

Step 6: Bring it all together

The most effective approach connects the prenup to the broader financial plan. Tax implications, estate documents, and retirement accounts all interact with inheritance clauses. Neptune's Blueprint helps couples organize these decisions in one place, pairing you with experienced attorneys, CFPs, and CPAs who coordinate the prenup with estate and tax planning from start to finish.

You don't have to figure this out in isolation. Working through inheritance planning as a team, with qualified professionals guiding the process, turns a potentially uncomfortable topic into shared clarity about your financial future together.