Prenuptial Agreements in Michigan: Enforceability and Disclosure

A prenuptial agreement in Michigan is a written, signed contract that a couple enters into before marriage to decide in advance how property, debts, spousal support, and estate rights will be handled if the marriage ends. Michigan courts will enforce one when it was entered into honestly, with full financial disclosure on both sides, and without pressure. Two statutes anchor the rules: MCL 557.28 keeps property contracts made before marriage in force after the wedding, and MCL 566.132 requires any agreement made in consideration of marriage to be in writing and signed.{¹}{²} The rest of the framework comes from case law, and judges scrutinize how the agreement was produced as closely as what it says.

What Makes a Prenup Enforceable

Michigan courts apply a three-part test set out in Rinvelt v. Rinvelt, 190 Mich. App. 372 (1991), and reaffirmed in Reed v. Reed, 265 Mich. App. 131 (2005).{³} When someone challenges an agreement, the judge asks three questions:

Was the agreement obtained through fraud, duress, or by hiding important financial information?
Was it so lopsided when signed that no reasonable person in the disadvantaged spouse’s position would have agreed?
Have facts changed so dramatically since the wedding that enforcing the original terms would now be deeply unfair?

The spouse challenging the agreement carries the burden of proof on all three questions, so the default position favors enforcement.{⁴} A judge still has discretion to set aside an agreement that has become a vehicle for extreme hardship, and the classic example is a long marriage where enforcement would leave one spouse destitute while the other walks away with millions. The threshold is high. Unequal is not the same as unconscionable.

Full Financial Disclosure

The Rinvelt court imposed a heightened duty of disclosure on both parties, recognizing that prenuptial negotiations carry “a special duty of disclosure not required in ordinary contract relationships.”{⁴} Each person needs to lay out their full financial picture before either side signs. Hiding a brokerage account or failing to mention an ownership stake in a business gives a judge exactly the kind of nondisclosure that voids the entire contract.

The usual exchange covers real estate, bank and investment accounts, retirement savings, business interests, and outstanding debts including student loans, mortgages, and credit card balances. Recent tax returns and pay stubs help verify income. This information is typically organized into schedules or exhibits attached to the agreement, creating a paper trail that proves both sides knew what they were giving up.

Disclosure does not have to be perfect down to the penny, but it must be honest and reasonably complete. Intentionally lowballing a business value or leaving out a retirement account is the kind of material nondisclosure that satisfies the first prong of the enforceability test.

What You Can Put in the Agreement

Michigan follows an equitable-distribution model in divorce, meaning a judge divides property fairly but not necessarily equally. A prenup lets you override that default by spelling out which assets stay separate and which become marital property subject to division.{¹}

Separate property typically includes assets owned before the marriage, future inheritances, and gifts from third parties. Classifying these items clearly in the agreement keeps them out of the pool a judge divides. The agreement can also address the marital home, specifying whether one spouse has the right to remain in the residence for a set period or whether the house will be sold and proceeds split according to a formula. Appreciation matters too. Without a prenup, a business one spouse owned before the marriage might become partly marital property if the other spouse contributed to its growth. A well-drafted provision can keep that appreciation separate or set a formula for sharing it.

Spousal support is the other big lever. You can waive support entirely, cap it at a fixed dollar amount, tie it to the length of the marriage, or use a formula that adjusts based on income at the time of divorce. Michigan courts generally honor these provisions, but they keep authority to step in when the result is extreme. An agreement that would leave one spouse unable to meet basic needs, or force them onto public assistance, faces serious scrutiny, especially when circumstances have shifted since signing. A spouse who was a working professional at signing but later became disabled has a strong argument that enforcement would be unconscionable.

What a Prenup Cannot Control

Michigan law draws a hard line at children. A prenuptial agreement cannot predetermine child custody, parenting time, or child support.{⁵} Those issues stay with the court because they must be decided on the child’s best interests at the time of separation, not years earlier. Language about custody or child support in a prenup is unenforceable, though it will not necessarily invalidate the rest of the agreement.

Estate and Retirement Waivers

Michigan’s Estates and Protected Individuals Code lets a spouse waive inheritance rights through a prenup. Under MCL 700.2205, a surviving spouse’s rights to an intestate share, homestead allowance, elective share, exempt property, and family allowance can all be waived, in whole or in part, by a signed writing entered into after fair disclosure.{⁶} A waiver of “all rights” in the other spouse’s property or estate operates as a complete renunciation of every benefit that would otherwise pass through intestate succession or under a will executed before the waiver. Courts take that language at face value. Sign a prenup with a broad estate waiver and you give up your right to inherit from your spouse even if they die without a will.

Retirement accounts governed by federal law create a trap. If one of you has a 401(k), pension, or other employer-sponsored plan covered by ERISA, a prenuptial waiver of survivor benefits is not enforceable. Federal law requires that the person waiving those rights be a “spouse,” and at the time of signing a prenup you are still a fiancé.{⁷} Under 29 U.S.C. § 1055, a valid waiver of survivor benefits requires three things: written consent by the participant’s spouse, designation of an alternate beneficiary, and witnessing by a plan representative or notary. Because those requirements can only be met after the marriage exists, the standard workaround is to include the retirement waiver in the prenup and confirm it in a postnuptial agreement signed shortly after the wedding. Skip that second step and the surviving spouse keeps their automatic right to survivor benefits regardless of what the prenup says.

This ERISA issue applies specifically to survivor annuity rights. A prenup can still address how the value of a retirement account gets divided during divorce through a qualified domestic relations order. Waiving monthly pension payments during the owner’s lifetime is generally permissible in a prenup. Waiving the survivor benefit that kicks in after the owner’s death is not.

Tax Consequences Worth Knowing

When a prenup requires one spouse to transfer property to the other as part of a divorce, federal tax law generally makes that transfer tax-free. Under 26 U.S.C. § 1041, no gain or loss is recognized on a property transfer between spouses or to a former spouse when the transfer is incident to the divorce, meaning it happens within one year after the marriage ends or is related to the divorce.{⁸}

The catch is basis. The person receiving the property inherits the transferor’s original cost basis, not the current fair market value. If your spouse bought stock for $10,000 and it is worth $100,000 when you receive it, you take over that $10,000 basis, and when you eventually sell, you owe tax on $90,000 in gains. A prenup that splits assets by current value without accounting for embedded tax liability can produce results that look equal on paper but are not equal after taxes.

Signing It Right

Michigan’s statute of frauds requires any agreement made in consideration of marriage to be in writing and signed by the party to be bound.{²} An oral promise about how you will divide property in a divorce is legally void. Both parties must sign.

Michigan does not require notarization or witnesses for the agreement to be valid, but having signatures notarized and witnessed is standard practice because it makes the agreement harder to challenge later. A notarized signature eliminates disputes about whether someone actually signed, and witnesses can testify that neither party appeared to be under pressure. If the agreement includes a waiver of estate rights under MCL 700.2205, the writing-and-signature requirement from that statute must also be satisfied.{⁶}

Timing

When you sign matters almost as much as what you sign. A prenup presented the night before the wedding, with no time for the other person to read it, consult a lawyer, or negotiate, practically invites a duress challenge. Michigan courts look at whether both parties had a reasonable opportunity to review and seek independent advice. Signing weeks or months before the ceremony removes the argument that anyone felt cornered.

Independent Legal Counsel

Michigan does not legally require each party to hire a separate attorney. From an enforceability standpoint, though, independent counsel for both sides is one of the strongest safeguards against a future challenge. When only one attorney drafts the agreement and the other party signs without independent advice, a court is more likely to find that the unrepresented spouse did not fully understand what they were giving up. When a party later claims duress or lack of understanding, the fact that they had their own lawyer reviewing the agreement is often enough to defeat the challenge. The cost of a second attorney is modest compared to the cost of having the entire agreement thrown out years later.

Why Michigan Courts Throw Prenups Out

Most prenuptial agreements that fail in Michigan fail for the same handful of reasons. Incomplete financial disclosure is the most common. If one spouse can show the other hid significant assets or debts, the entire agreement is vulnerable under the first prong of the Rinvelt test.{⁴}

Duress and coercion claims are common but harder to win. Michigan courts have generally held that threatening not to go through with the wedding unless the other person signs is not, by itself, duress. The analysis focuses on whether the disadvantaged party had adequate time and opportunity to review the agreement, negotiate changes, and consult a lawyer. A last-minute ambush combined with no access to independent counsel paints a much worse picture than a firm request made months in advance.

Changed circumstances provide the third avenue for invalidation. Courts look for truly dramatic shifts: a spouse who becomes permanently disabled, a long marriage in which one party sacrificed a career to raise children, or a catastrophic financial reversal no one could have anticipated. Ordinary changes in income or lifestyle that come with aging do not typically meet this bar. The agreement does not need to produce an equal result to survive. It just cannot produce one that shocks the conscience.{³}

1
Michigan Legislature. Michigan Compiled Laws 557.28 – Contract Relating to Property Made in Contemplation of Marriage
2
Michigan Legislature. Michigan Compiled Laws 566.132 – Agreements Required to Be in Writing
3
FindLaw. Reed v Reed
4
CaseMine. Rinvelt v Rinvelt
5
Michigan Legislature. Senate Bill 160 – Uniform Premarital and Marital Agreement Act
6
Michigan Legislature. Michigan Compiled Laws 700.2205 – Waiver of Surviving Spouse Rights
7
Office of the Law Revision Counsel. 29 USC 1055 – Requirement of Joint and Survivor Annuity and Preretirement Survivor Annuity
8
Office of the Law Revision Counsel. 26 USC 1041 – Transfers of Property Between Spouses or Incident to Divorce