Wisconsin marital-property agreement formalities
A marital-property agreement must be a document signed by both spouses; only the spouses may be parties, and consideration is unnecessary.
Wis. Stat. § 766.58(1)WI · Manually written guide
Prenup laws in Wisconsin
Wisconsin uses its marital-property agreement framework in section 766.58 rather than a verbatim Uniform Premarital Agreement Act chapter.Wis. Stat. § 766.58(1)Wis. Stat. § 766.58(3)Wis. Stat. § 766.58(6)(b)
The statute covers signed-document formalities, child-support limits, permitted marital-property subjects, and Wisconsin-specific enforcement rules.Wis. Stat. § 766.58(1)Wis. Stat. § 766.58(3)Wis. Stat. § 766.58(6)(b)
Evidence tiersection verified
Package versionwi-2026-07-23.3
Authorities18
Reviewed2026-07-23
Effective through2026-07-23
Formation and lifecycle
Execution requirements to investigate
Wisconsin amendment and revocation rule
A marital-property agreement may be amended or revoked only by a later marital-property agreement.
Wis. Stat. § 766.58(4)Wisconsin premarital effectiveness rule
People intending to marry may execute the agreement as if married, but it becomes effective only upon marriage.
Wis. Stat. § 766.58(5)What the agreement addresses
Permitted subjects and legal limits
Wisconsin permitted property subjects
Subject to listed statutory limits, spouses may contract about property rights, management, disposition at dissolution or death, support, estate arrangements, nonprobate transfers, choice of law, and other lawful property matters.
Wis. Stat. § 766.58(3)Wisconsin child-support nonimpairment rule
A marital-property agreement may not adversely affect a child's right to support.
Wis. Stat. § 766.58(2)Wisconsin agreement-based death transfers
An agreement may address death disposition and qualifying nonprobate transfers, but chapter 854 applies and dissolution revokes specified provisions.
Wis. Stat. § 766.58(3)(c), (e)–(f), (3m)Wisconsin statutory unconscionability defense
The resisting spouse may prove the agreement was unconscionable when made; the court decides unconscionability as a matter of law.
Wis. Stat. § 766.58(6)(a), (8)Wisconsin support and public-assistance floors
Support may be modified or eliminated, but during marriage a spouse may not be left without necessary and adequate support, and a court may order support needed to avoid public-assistance eligibility at dissolution or death.
Wis. Stat. § 766.58(3)(d), (9)Wisconsin three-part premarital fairness framework
Button requires fair and reasonable financial disclosure, free and voluntary entry, and substantively fair divorce provisions; the challenger bears the persuasion burden.
Button v. Button, 131 Wis. 2d 84, 95–99, 388 N.W.2d 546 (1986)Wisconsin substantive-fairness timing review
Wisconsin's divorce-equity review examines whether circumstances at divorce were beyond the parties' contemplation; ordinary anticipated risks do not alone rescue a spouse from an unwise agreement.
Warren v. Warren, 147 Wis. 2d 704, 709–11, 433 N.W.2d 295 (Ct. App. 1988)Wisconsin contract-construction rule
A valid premarital agreement is a binding contract interpreted under ordinary construction rules; courts may not redraft it, and it controls covered property division.
Heise v. Heise, 2004 WI App 186, ¶¶ 15–16Wisconsin affirmative homestead waiver
Wisconsin favors premarital agreements, but waiver of statutory homestead protection must be affirmative and supported by the agreement's language.
Jones v. Estate of Jones, 2002 WI 61, ¶¶ 16–18, 253 Wis. 2d 158, 646 N.W.2d 280Wisconsin property-division agreement review
A written pre- or postmarital property-distribution agreement is a statutory property-division factor but is not binding if inequitable to either party; equity is presumed.
Wis. Stat. § 767.61(3)(L)Wisconsin custody and support boundary
Custody and placement turn on current statutory best interests, while support is judicially determined under the percentage standard and statutory factors.
Wis. Stat. §§ 767.41, 767.511Process evidence
Financial disclosure, voluntariness, counsel, and timing
Wisconsin statutory voluntary-execution defense
A marital-property agreement is not enforceable if the resisting spouse proves that execution was not voluntary.
Wis. Stat. § 766.58(6)(b)Wisconsin statutory disclosure-and-notice defense
The resisting spouse may establish nonenforcement by proving both lack of fair and reasonable disclosure under the circumstances and lack of notice of the other spouse's property or financial obligations before execution.
Wis. Stat. § 766.58(6)(c)Wisconsin representation boundary
Joint representation, one-sided representation, or one party's lack of counsel does not by itself make an agreement unconscionable or otherwise unenforceable.
Wis. Stat. § 766.58(8)Wisconsin actual-knowledge substitute boundary
For Button disclosure review, only actual knowledge of the other party's assets and values substitutes for disclosure; constructive or imputed knowledge is insufficient.
Mary A. Kordus v. Daniel Kordus, No. 2008AP111; Button; SchumacherHypotheticals, not outcomes
Practical examples
These examples show how document facts can intersect with the cited sources. They do not predict a court result.
The marital-property classification clause
A clause reclassifies future business income and appreciation. Wisconsin's marital-property content provisions provide the starting categories for that analysis.Wis. Stat. § 766.58(3)
Ask local counsel
How does section 766.58 interact with Wisconsin's broader marital-property system for these assets?
The agreement and financial statement differ
The signed agreement describes an asset differently from the attached financial statement. Wisconsin's enforcement framework makes the execution-time financial record important.Wis. Stat. § 766.58(6)(b)
Ask local counsel
What did each party understand about the asset when the document was signed?
Common starting points
Wisconsin prenup FAQs
Answers are deliberately scoped to the cited evidence package and should be checked against current law.
What form does Wisconsin require?
Section 766.58(1) uses a signed document and does not require consideration.Wis. Stat. § 766.58(1)
What child-related limit appears?
Section 766.58 preserves child-support protections from adverse contractual treatment.Wis. Stat. § 766.58(3)
Where are Wisconsin's enforcement rules found?
Section 766.58(6) supplies the state-specific enforcement framework catalogued by the package.Wis. Stat. § 766.58(6)(b)
Prepare for independent advice
Questions for a Wisconsin lawyer
Bring the agreement, every exhibit, prior drafts, disclosure records, and a signing timeline. Then use the source-linked questions as an interview guide.
- 01
Is the complete document signed by both prospective spouses and limited to them as parties?Wis. Stat. § 766.58(1)
- 02
Can each clause be mapped to subsection (3) and its incorporated limits?Wis. Stat. § 766.58(3)
- 03
Does any term reduce or predetermine a child's support right?Wis. Stat. § 766.58(2)
- 04
Does the clause create a valid transfer under every applicable death-transfer rule?Wis. Stat. § 766.58(3)(c), (e)–(f), (3m)
- 05
Is the claimed change contained in a later qualifying marital-property agreement?Wis. Stat. § 766.58(4)
- 06
Did the contemplated marriage occur, and when did the agreement become effective?Wis. Stat. § 766.58(5)
- 07
What facts at execution support the statutory unconscionability defense?Wis. Stat. § 766.58(6)(a), (8)
- 08
What evidence shows whether the spouse executed freely and voluntarily?Wis. Stat. § 766.58(6)(b)
- 09
What disclosure and actual notice existed before signing for each material asset and obligation?Wis. Stat. § 766.58(6)(c)
- 10
How did representation affect actual understanding, voluntariness, disclosure, and fairness?Wis. Stat. § 766.58(8)
- 11
Would the clause violate either statutory support floor at the relevant time?Wis. Stat. § 766.58(3)(d), (9)
- 12
Does the agreement satisfy each procedural and substantive fairness requirement?Button v. Button, 131 Wis. 2d 84, 95–99, 388 N.W.2d 546 (1986)
- 13
What did the spouse actually know about nature and value before signing?Mary A. Kordus v. Daniel Kordus, No. 2008AP111; Button; Schumacher
- 14
Were the circumstances making enforcement unfair reasonably beyond contemplation at execution?Warren v. Warren, 147 Wis. 2d 704, 709–11, 433 N.W.2d 295 (Ct. App. 1988)
- 15
What property does the agreement actually cover under its text?Heise v. Heise, 2004 WI App 186, ¶¶ 15–16
- 16
Does the text clearly and affirmatively waive the specific homestead protection?Jones v. Estate of Jones, 2002 WI 61, ¶¶ 16–18, 253 Wis. 2d 158, 646 N.W.2d 280
- 17
Is the agreement equitable under section 767.61 and Button at the time relevant to divorce?Wis. Stat. § 767.61(3)(L)
- 18
Does any term attempt to bind a future custody or support determination?Wis. Stat. §§ 767.41, 767.511
Known boundaries
Package limitations
- This package encodes the cited official statutory sections but does not decide how a court would apply them to particular facts.
- Later amendments, decisions, court rules, conflicts rules, and local practice require continuing review.
- Attorney review is optional and can add a professional opinion; this package supports transparent research and issue spotting without prior endorsement.