Parties Can Enter into Post Nuptial Agreements Regarding Ownership of Assets and Spousal Support and Change Ownership from Community to Separate Property
California Postnuptial and Transmutation Agreements: What They Can—and Cannot—Do
Most people understand the basic purpose of a prenuptial agreement. Far fewer people know that a California postnuptial agreement can establish or change property rights after the couple is already married.
California spouses can also enter into agreements after marriage. These agreements are commonly called postnuptial agreements, postmarital agreements, or marital property agreements.
A carefully prepared postnuptial agreement can identify separate and community property, change the character of existing property, establish rules for future earnings and acquisitions, allocate responsibility between the spouses for particular debts, and address how property may be divided if the marriage ends.
But a postnuptial agreement is not automatically enforceable merely because both spouses signed it. Married spouses owe each other fiduciary duties of the highest good faith and fair dealing. A postnuptial agreement also does not necessarily prevent an existing or future creditor from reaching property that would otherwise be liable for a debt.
Those limitations are particularly important when one spouse wants to start a business or borrow a substantial amount of money.
A common question about business debt
Consider this question:
My spouse and I live in California. I am the primary income earner, although my spouse also works. My spouse wants to borrow a substantial amount of money to start a business. I do not support the plan and do not want the assets and income I have accumulated exposed to the business risk.
Can we sign an agreement that separates our bank accounts, home equity, investments and future earnings so that my spouse takes the business risk without putting my property at risk?
The short answer
A postnuptial or marital property agreement may be part of a solution, but the answer is not as simple as signing a document that says, “Your debts are yours and my assets are mine.”
The spouses may agree to change the character of property between themselves. Whether the agreement protects property from a bank, judgment creditor, landlord, vendor or other third party is a different question.
The analysis should include:
- The present character of each asset;
- Whether the proposed loan already exists or is only being considered;
- Which spouse will sign or guarantee the debt;
- Whether community property will secure the loan;
- Whether either spouse will personally guarantee the business obligations;
- Whether jointly titled real property will be pledged;
- Whether a proposed transfer could prejudice an existing or reasonably anticipated creditor;
- How future earnings and newly acquired property will be characterized; and
- Whether additional business entities, contracts or insurance should be used.
A family lawyer can address marital property ownership. Depending on the circumstances, the spouses may also need advice from a business, tax, estate-planning or bankruptcy attorney.
What is a transmutation?
A transmutation is an agreement or transfer that changes the legal character of marital property.
California Family Code section 850 permits married spouses to:
- Change community property into the separate property of either spouse;
- Change one spouse’s separate property into community property; or
- Change one spouse’s separate property into the other spouse’s separate property.
Examples might include:
- Changing a community-property residence into one spouse’s separate property;
- Changing a separately owned residence into community property;
- Converting a community investment account into separate property;
- Giving one spouse a separate-property interest in a business; or
- Defining how future earnings or future acquisitions will be characterized.
A transmutation may be included in a broader postnuptial agreement, but the terms are not necessarily interchangeable. A postnuptial agreement may establish several financial rules, while a transmutation specifically changes the character or ownership of particular property.
What does California Family Code section 852 require?
For real or personal property, Family Code section 852 generally requires:
- A writing;
- An express declaration changing the property’s character or ownership; and
- The signature, consent, joinder or acceptance of the spouse whose property interest is adversely affected.
The document must communicate the change directly. Language that merely suggests an intention to make a gift or refers generally to estate planning may be insufficient.
In Estate of MacDonald, the California Supreme Court concluded that the writing itself must expressly state that the characterization or ownership of the property is being changed. Outside evidence ordinarily cannot supply an intention that is missing from the document.
The California Supreme Court reinforced the importance of these formalities in In re Marriage of Valli. In that case, community funds were used to purchase a life insurance policy titled in one spouse’s name. The title did not by itself satisfy California’s transmutation requirements. The policy remained community property because there was no qualifying express written declaration.
The practical lesson is important: putting an asset in one spouse’s name does not necessarily make it that spouse’s separate property.
Does a transmutation protect property from business creditors?
Not necessarily.
California Family Code section 910 generally provides that the community estate is liable for a debt incurred by either spouse during marriage, regardless of which spouse incurred the debt or which spouse manages the property.
Family Code section 913 generally provides that one spouse’s separate property is not liable for a debt incurred solely by the other spouse. There are exceptions, including certain debts for the necessities of life.
A valid agreement that changes community property into separate property may therefore affect which assets are available to satisfy a future debt. But several important restrictions apply:
- A private agreement between spouses does not automatically alter a creditor’s contractual rights.
- A spouse who signs or guarantees a loan may remain personally liable.
- Property pledged as collateral remains exposed to the secured debt.
- A transmutation is subject to fraudulent-transfer law under Family Code section 851.
- A transfer made to hinder, delay or defraud a creditor may be attacked.
- An agreement generally cannot remove a preexisting lien.
- A transmutation of real property is not effective against third parties without notice unless it is properly recorded.
- Property may remain exposed if the spouses do not properly retitle or administer it after signing the agreement.
A transmutation can therefore be one component of legitimate financial planning, but it should not be marketed or treated as a guaranteed asset-protection device.
Can spouses keep future earnings separate?
California’s default rule is that property acquired during marriage while the spouses are domiciled in California is community property. That ordinarily includes employment earnings received before the date of separation.
Family Code section 1500 permits spouses to alter statutory property rights through a marital property agreement. A carefully drafted agreement may establish that future earnings and property acquired with those earnings will be the earning spouse’s separate property.
The document should address more than the paychecks themselves. It should explain how the spouses will treat:
- Bonuses and commissions;
- Retirement contributions and benefits;
- Business income and appreciation;
- Investments purchased with earnings;
- Joint household expenses;
- Jointly titled accounts;
- Income taxes;
- Mortgage payments and home improvements; and
- Property purchased with both separate and community funds.
The spouses must then follow the agreement. Repeatedly mixing separate funds into joint accounts or using jointly owned funds without adequate records can create tracing and enforcement problems.
Why fiduciary duties matter
A postnuptial agreement is negotiated after the parties are already married. That makes it different from an ordinary arm’s-length contract.
Under Family Code section 721, spouses owe each other the highest duty of good faith and fair dealing. Neither spouse may take unfair advantage of the other. They must provide truthful information concerning material financial facts and allow meaningful access to relevant records.
When an interspousal transaction gives one spouse an unfair advantage, a presumption of undue influence may arise. Depending on the nature of the transaction, the spouse receiving the advantage may have to prove that the agreement was:
- Entered freely and voluntarily;
- Made with knowledge of the relevant facts; and
- Signed with a complete understanding of its purpose and legal effect.
California courts have enforced postmarital agreements when the evidence established informed, voluntary and fair negotiations. They have also rejected or set aside interspousal transactions when those protections were absent.
Must the spouses disclose every asset and debt?
The original version of this article stated categorically that all assets and debts “must” be disclosed and that the entire agreement could otherwise be invalid.
A more precise explanation is that California’s fiduciary rules require full disclosure of material financial information relevant to the transaction. Formal divorce disclosure forms are not automatically required merely because married spouses negotiate a postnuptial agreement while they remain married.
Nevertheless, the best drafting practice is usually to attach detailed financial schedules identifying:
- Real property;
- Bank and investment accounts;
- Retirement plans;
- Businesses and professional practices;
- Vehicles and valuable personal property;
- Separate-property claims;
- Loans, credit cards and tax liabilities;
- Current income;
- Material contingent liabilities; and
- Reasonable estimates of value.
Each spouse should acknowledge receiving and reviewing the information. If an exact value is unknown, the agreement should identify that fact rather than create a false appearance of precision.
Should each spouse have a separate lawyer?
Independent counsel is strongly recommended.
One attorney ordinarily should not advise both spouses about an agreement that changes their competing property or support rights. The attorney preparing the document can represent one spouse. The other spouse should have sufficient time to obtain independent advice from a different attorney.
Separate representation helps establish that each spouse:
- Understood the default California property rules;
- Understood the rights being retained, transferred or waived;
- Had an opportunity to request additional information;
- Was not rushed or pressured;
- Understood the foreseeable consequences; and
- Made an informed and voluntary decision.
Independent counsel is especially important when the proposed agreement substantially favors one spouse, transfers an interest in a residence or business, addresses future earnings, or limits potential spousal support.
Can a postnuptial agreement address spousal support?
A postnuptial agreement may address potential spousal support, including a limitation or waiver, but enforceability is highly fact-specific.
California courts closely examine how such provisions were negotiated, whether each spouse was represented, whether the financial information was adequate, whether the agreement was voluntary, and whether enforcement would be unconscionable or contrary to public policy.
No attorney should promise that a future court will automatically enforce a spousal-support waiver simply because it appears in a signed postnuptial agreement.
The way to ‘bullet proof’ your postnuptial agreement concerning spousal support is to ensure the agreement is “fair.” Obviously “fair” is subjective. But as U.S. Supreme Court Justice Potter Stewart famously wrote in a case concerning whether a French movie was too obscene and should be banned in the U.S. he wrote that he could not easily define hard-core pornography, but added: “I know it when I see it, California Bench Officers will know it when they see an unfair spousal support clause in a California Postnuptual Agreement or a California Prenuptial Agreement.
What cannot be conclusively decided in a postnuptial agreement?
Spouses should not rely on a postnuptial agreement to predetermine future child custody or child support.
Custody decisions must be based on the child’s best interests when the issue is presented to the court. A child’s right to support cannot be eliminated by an agreement between the parents.
An agreement also cannot enforce provisions that violate criminal law or public policy.
A practical process for creating a postnuptial agreement
A careful process ordinarily includes the following steps:
- Identify each spouse’s goals.
- Determine the present character of every significant asset and debt.
- Gather supporting records and valuations.
- Prepare written financial disclosures.
- Identify existing and reasonably anticipated creditors.
- Determine whether specific property will be transmuted.
- Draft direct, asset-specific language.
- Allow the other spouse adequate time to review the proposal.
- Encourage independent legal representation.
- Revise the agreement through documented negotiations.
- Execute the agreement with the appropriate formalities.
- Record documents affecting real property when appropriate.
- Retitle accounts and other assets as required.
- Coordinate the agreement with tax, business and estate-planning documents.
- Maintain records showing that the spouses followed the agreement.
When might a postnuptial agreement make sense?
A postnuptial agreement may be worth considering when:
- One spouse intends to start or purchase a business;
- One spouse plans to incur significant investment risk;
- The spouses disagree about borrowing or financial management;
- One spouse receives or expects a substantial inheritance;
- Family members are providing money for a residence or business;
- The spouses want to clarify ownership of a home;
- One spouse leaves the workforce to care for children;
- The couple wants to modify an existing prenuptial agreement;
- Separate and community funds have been mixed;
- The spouses want to clarify future earnings and retirement contributions; or
- The couple wants financial certainty while working to preserve the marriage.
Speak with a Woodland Hills postnuptial-agreement attorney; your strategy session is free and without obligation.
Postnuptial and transmutation agreements require more than a downloaded form. The language must fit the particular assets, debts, risks and objectives of the spouses. The negotiation and disclosure process can be just as important as the final document.
Top-rated Woodland Hills attorney Galen Gentry has more than 30 years of experience handling California family-law and marital-property matters. Galen Gentry Law Group assists clients with drafting, reviewing, negotiating and evaluating prenuptial and postnuptial agreements.
If you are considering a postnuptial agreement—or your spouse has asked you to sign one—call (310) 282-7521 or contact Galen Gentry Law Group online to schedule a free, no-obligation strategy session.
This article was published November 21, 2022 and updated on July 24, 2026 by Attorney Galen Gentry