What Makes a Prenup Invalid? 5 Reasons Courts Reject Them

Are prenups enforceable? In every US state, yes — but only when they satisfy specific procedural requirements. Most invalidated prenups fall into 5 categories: inadequate disclosure, lack of independent counsel, duress, unconscionability, and procedural defects. Each has a textbook case behind it. Knowing them is the cheapest insurance against signing something that won't hold up. This page is general information, not legal advice.

1. Inadequate financial disclosure

The single most-cited reason. UPAA §6 and the equivalents in non-UPAA states require that each spouse have a "fair and reasonable disclosure" of the other\'s financial situation. Vague descriptions ("various accounts") or omitting major assets (a business, a brokerage account) is enough.

Case to know: Ware v. Ware, 224 W.Va. 599 (2009). The husband listed assets generally but omitted specific values and recent appreciation. The West Virginia Supreme Court struck the agreement down, holding that adequate disclosure requires specific values — not generic descriptions.

How to avoid it: Sworn schedules with specific dollar values, dated within 90 days of signing. Attach account statements, recent tax returns, and a business valuation if applicable.

2. Lack of independent counsel

California requires it by statute (Cal. Fam. Code §1615(c)(1)) — or an express written waiver after written warning of the agreement\'s terms and effect. Most other states don\'t require it, but courts everywhere weigh its absence heavily. Joint representation by a single attorney creates a conflict of interest that gives the disadvantaged spouse a clean route to invalidation.

How to avoid it: Each spouse retains their own family law attorney from the start. The cost difference between one attorney and two is small compared to the enforceability difference.

3. Duress and involuntariness

The clearest fact pattern: signing the day before the wedding. Family invited, dress purchased, flights booked. A spouse asked to sign in that moment can credibly argue they didn\'t have a real choice. California codified this concern with the 7-day rule (Cal. Fam. Code §1615(c)(2)) — at least seven calendar days between presenting the final agreement and signing it.

Case to know: In re Marriage of Bonds, 24 Cal.4th 1 (2000). Barry Bonds and his fiancée signed a prenup the day before the wedding without independent counsel for her. The California Supreme Court upheld the prenup under then-existing law. The Legislature responded by passing the modern §1615(c) — independent counsel + 7-day rule — so California prenups today face a much higher bar than Bonds itself did.

How to avoid it: Sign at least 30 days before the wedding. Document the timeline — when the agreement was first presented, when revisions happened, when the final version was signed. The paper trail is the defense.

4. Unconscionability

A prenup so one-sided that enforcing it shocks the conscience. Leaving one spouse with literally nothing while the other keeps everything is the textbook example. Many states apply a "two-look" test — unconscionable at execution AND unconscionable at enforcement — meaning a prenup that was reasonable in 2005 can be unenforceable in 2025 if circumstances changed dramatically.

Cases to know: DeMatteo v. DeMatteo, 436 Mass. 18 (2002) — the leading two-look case. Gross v. Gross, 11 Ohio St.3d 99 (1984) — applies the same standard in Ohio.

How to avoid it: Build in some balance. A modest support provision, a sunset clause, or a partial-share arrangement is more enforceable than a total waiver. Talk to your attorney about what your state\'s courts will and won\'t bless.

5. Procedural defects

State-specific signing rules that DIY prenups miss. New York requires the agreement to be acknowledged with the formalities required to record a deed (Matisoff v. Dobi, 90 N.Y.2d 127 — failure renders the prenup unenforceable regardless of how clearly the parties intended to be bound). Minnesota requires two witnesses plus notarization. California requires the 7-day rule and the independent counsel rule.

How to avoid it: Use a family law attorney licensed in your state. Procedural rules are the kind of thing generalists miss and specialists don\'t.

How to make sure your prenup is enforceable

Each of the five reasons is preventable. None require the other spouse\'s cooperation beyond signing — they\'re about the procedure on your own side. Plan for time, hire your own attorney, do the disclosure work, watch the state-specific rules.

To run your specific situation against these five factors, take the prenup quiz. To see your state\'s specific rules, find your state in the cost guide or the lawyer directory.