Postnuptial Agreements and Asset Protection in Florida

A postnuptial agreement is a contract between spouses, signed after the wedding, that overrides Florida’s default equitable distribution rules. For married couples who did not sign a prenuptial agreement before the ceremony, a postnuptial agreement does the same work. It does not require a divorce to be pending.

Florida’s exemptions (homestead, tenancy by the entirety) protect assets from third-party creditors, but the family court has broad discretion to divide marital property regardless of those exemptions. A postnuptial agreement sets enforceable terms that the court must follow when dividing property, provided the agreement meets Florida’s enforceability requirements under the Casto v. Casto standard.

How Does Florida Law Treat Postnuptial Agreements Differently Than Prenups?

Prenuptial agreements in Florida fall under the Uniform Premarital Agreement Act, codified at § 61.079. Postnuptial agreements do not. Florida has no statute governing postnuptial agreements, so courts apply common law principles established by the Florida Supreme Court in Casto v. Casto, 508 So. 2d 330 (Fla. 1987).

Postnuptial agreements face stricter judicial scrutiny. Under the UPAA, unfairness by itself does not defeat a prenuptial agreement. Section 61.079(7)(a) lets the challenging spouse show that the agreement was not executed voluntarily, or that it was unconscionable when signed, with no adequate disclosure and no written waiver. Fraud, duress, coercion, or overreaching defeats the agreement as well. Under Casto, a postnuptial agreement can also be vacated on the ground that it makes an unfair or unreasonable provision for the challenging spouse, given the parties’ circumstances at the time they signed it.

The Casto decision creates two independent grounds for challenging a postnuptial agreement. The first is that the agreement was obtained through fraud, duress, coercion, misrepresentation, or overreaching. The second requires the challenging spouse to show that the agreement makes an unfair or unreasonable provision, given the parties’ ages, health, education, and financial status, and that it is disproportionate to the defending spouse’s means. Once unreasonableness is established, a presumption of concealment or inadequate knowledge arises and the burden shifts to the defending spouse.

A prenuptial agreement between parties with vastly unequal bargaining power will generally be enforced if disclosure was adequate. A postnuptial agreement with identical terms may be vacated if the court finds the outcome unreasonable, unless the defending spouse rebuts the presumption that finding raises. Courts apply this heightened scrutiny because spouses negotiating during a marriage are not dealing at arm’s length the way engaged parties are.

What Can a Postnuptial Agreement Cover?

Postnuptial agreements in Florida can address the same financial matters as prenuptial agreements. The agreement can:

• Define which assets are separate property and which are marital property subject to division.
• Establish, modify, waive, or eliminate spousal support.
• Allocate responsibility for debts incurred before and during the marriage.
• Address the disposition of property at death, including provisions that coordinate with wills, trusts, and life insurance designations.

A postnuptial agreement cannot affect a child’s right to support. Florida courts determine child custody and child support based on the child’s best interests at the time of separation, and no marital agreement can override that authority.

One of the most common uses of a postnuptial agreement is reclassifying assets acquired during the marriage. Florida’s default rule treats most assets acquired by either spouse during the marriage as marital property subject to equitable distribution under § 61.075. That includes a business started during the marriage, an investment account funded with one spouse’s earnings, or real estate purchased in one spouse’s name. A postnuptial agreement can designate those assets as the separate property of the acquiring spouse. Without the agreement, the family court would divide them.

What Makes a Postnuptial Agreement Enforceable in Florida?

Florida courts enforce a postnuptial agreement that is in writing, signed voluntarily by both spouses, and made with full financial disclosure. They also test its terms for fairness under Casto.

Writing and signature. The agreement must be in writing and signed by both spouses. If it also waives a spouse’s rights in the other’s estate, section 732.702(1) calls for two subscribing witnesses.

Voluntariness. Both spouses must enter into the agreement without coercion. Section 61.079(7)(a)1 makes involuntary execution a separate ground for challenging a prenuptial agreement. For a postnuptial agreement, the same conduct falls under the first Casto ground. The Florida Supreme Court directed trial judges to examine the circumstances of signing closely. An agreement presented during a period of marital crisis, especially when one spouse threatens divorce unless the other signs, faces particular scrutiny.

Full financial disclosure. Each spouse must provide the other with a complete picture of their income, assets, and liabilities. In Casto, the court held that an agreement unreasonable on its face raises a presumption that the defending spouse concealed the finances or the challenging spouse lacked knowledge of them. Attaching current financial statements, tax returns, and account summaries as exhibits to the agreement creates a record of the full disclosure that rebuts the presumption.

Independent legal counsel. Separate attorneys for each spouse are not required, and Casto reaffirms that the competence of a spouse’s lawyer is not a ground to vacate a postnuptial agreement. The conduct surrounding counsel still bears on coercion. In Casto, the husband demanded that his wife dismiss her lawyer and retain one who would let her sign.

Substantive fairness. The Casto standard allows courts to vacate a postnuptial agreement based on unreasonableness combined with inadequate knowledge, even if the disclosure was technically provided. The question is whether the challenging spouse actually understood the financial information. The UPAA treats prenuptial agreements differently. Unconscionability alone is insufficient to void a prenup without a concurrent disclosure failure.

When Does a Postnuptial Agreement Make Sense for Asset Protection?

A postnuptial agreement makes sense for a spouse who starts a business during the marriage. That spouse faces the risk that the business will be classified as marital property and subject to equitable distribution. Without a postnuptial agreement, the non-owner spouse may be entitled to a share of the business’s value, potentially forcing a buyout, valuation dispute, or liquidation. A postnuptial agreement can designate the business as the owner-spouse’s separate property and waive the non-owner spouse’s claim to its value.

A spouse who receives a substantial inheritance during the marriage should keep those funds segregated from marital assets to preserve their separate character. Inherited funds deposited into a jointly titled account are presumed marital under section 61.075, and the inheriting spouse carries the burden of proving otherwise. A postnuptial agreement can confirm that specific inherited assets remain separate property even if some commingling has occurred, though the agreement’s effectiveness depends on meeting the Casto enforceability standards.

A couple facing increased liability exposure (a spouse entering a high-risk profession, for example) may use a postnuptial agreement to concentrate assets in the non-liable spouse’s name. A postnuptial agreement executed before any specific liability exists creates a contractual basis for the asset allocation that predates the creditor’s claim. An agreement signed after a claim has arisen or is reasonably anticipated carries fraudulent transfer risk, though the analysis depends on whether the transfer left the debtor spouse with enough assets to pay existing debts.

Couples who married without a prenuptial agreement and later realize they need defined property boundaries can set them in a postnuptial agreement. The postnuptial agreement must then satisfy the stricter Casto standard rather than the UPAA’s rules for premarital agreements.

Postnuptial Agreements and Third-Party Creditors

A postnuptial agreement defines how assets are divided between spouses, but it does not create a barrier against third-party creditors the way an asset protection trust or exempt account does. Divorce protection and creditor protection serve different purposes, and a postnuptial agreement addresses only the first.

If a judgment creditor pursues one spouse, the postnuptial agreement does not prevent the creditor from reaching that spouse’s assets. A creditor with a judgment can still levy the debtor spouse’s separate property, garnish wages, and execute against assets titled in that spouse’s name, regardless of what the postnuptial agreement says.

The agreement’s designation of separate property settles ownership between the spouses. Against a creditor it settles nothing, because the creditor takes an asset as it is titled and can attack a retitling as a transfer made without reasonably equivalent value.

Whether a transfer between spouses survives depends on when it happened and on what the transferring spouse got for it. A transfer made after a claim has arisen can be challenged as a fraudulent transfer, regardless of whether the transfer was made through a postnuptial agreement.

For people whose primary concern is protecting assets from lawsuits, judgments, or business liabilities rather than from divorce, a postnuptial agreement is not the right tool. Irrevocable trusts, LLCs, and offshore structures provide creditor protection that a marital agreement cannot replicate.

Postnuptial Agreements vs. Prenuptial Agreements

Factor	Prenuptial Agreement	Postnuptial Agreement
Governing law	§ 61.079 (UPAA)	Common law; Casto v. Casto
When executed	Before marriage	During marriage
Consideration	Marriage itself	Mutual promises within the agreement
Unfairness standard	Unfair terms alone are not a ground; unconscionability at signing counts only with a disclosure failure under § 61.079(7)(a)3	May be vacated if unfair and disproportionate to the defending spouse’s means, after which the burden shifts to that spouse
Scrutiny of execution	Voluntariness tested under § 61.079(7)(a)1	Trial judges examine the circumstances of signing under Casto
Disclosure requirement	Relevant only within the unconscionability route	Unreasonableness triggers a presumption of concealment or inadequate knowledge
Counsel	Not required but recommended	Not required; incompetent legal advice is not a ground to vacate

Because courts scrutinize postnuptial agreements more closely, a postnuptial agreement has to be drafted and documented more carefully than a prenuptial agreement. A postnuptial agreement that would survive challenge as a prenup may fail under the Casto standard if the court determines the outcome is unreasonable given the parties’ relative circumstances.

Limitations

Postnuptial agreements in Florida cannot override every divorce-related obligation. An alimony waiver is enforceable under Casto, but it stays open to both grounds of challenge recognized in that decision. Child support cannot be waived or modified by agreement.

The Casto standard’s unfairness test creates a practical ceiling on how one-sided a postnuptial agreement can be. An agreement that leaves one spouse with substantially all marital assets while the other receives little or nothing is vulnerable to challenge. The more imbalanced the agreement, the greater the burden on the defending spouse to demonstrate that the challenging spouse entered into it knowingly and without coercion.

A postnuptial agreement also does not shield assets from fraudulent transfer claims. A married couple that signs a postnuptial agreement transferring the debtor spouse’s assets to the non-debtor spouse after a claim has arisen faces the same scrutiny under Florida’s Uniform Fraudulent Transfer Act as any other transfer. The agreement does not provide a defense to avoidance actions simply because the transfer was made under a marital contract.

Protecting assets from divorce in Florida requires coordinating multiple tools. Exemptions, entity structures, and marital agreements each cover different risks, and a postnuptial agreement addresses only the property-division question between spouses.