Montana Prenuptial Agreement

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In re Marriage of Shirilla, 2004 MT 28, 319 Mont. 385, 89 P.3d 1

‍The Montana Supreme Court invalidated a PMA between a Butte physician and his Russian fiancée — who spoke limited English, was facing visa expiration, and had given up her home and job in Russia — holding that the combination of language barriers, immigration-timing pressure, and token contractual maintenance ($5,000 if divorce <2 years, $7,500 if >2 years) rendered her execution involuntary under § 40-2-608(1)(a), and the court awarded her $1,000/month maintenance for 20 months after invalidation.

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In re Marriage of Shiffman, 2023 MT 5N

‍In a noncitable memorandum opinion, the Court affirmed invalidation of an alleged PMA from a 1998 marriage on both involuntariness and unconscionability grounds because the wife had no independent counsel, denied signing, the schedule listed property she did not acquire until years later (sewing machine, computer, "Cabin C" not yet built), and the supposed drafting attorney could not recall preparing the document.

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In re Marriage of Stout/Gollehon, 261 Mont. 10, 861 P.2d 856 (1993)‍

Montana's first post-UPAA enforcement decision held that a wife's later regret about her husband's post-marital conduct (terminating a lease) did not render her original execution involuntary, establishing that "voluntariness" under § 40-2-608(1)(a) is judged at the time of signing based on then-existing circumstances.

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Wilkes v. Estate of Wilkes, 2001 MT 118, 305 Mont. 335, 27 P.3d 433

‍The Court enforced a PMA signed two days before the wedding by a 21-year-old developmentally disabled wife who had no independent counsel against a 62-year-old husband in poor health, holding that capacity and unconscionability challenges failed where the wife was mentally competent to understand the agreement and the husband had a legitimate purpose (preserving assets for his three children from a prior marriage).

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In re Marriage of Hutchins, 2018 MT 286, 393 Mont. 530, 432 P.3d 184

‍The Court enforced a PMA signed one week before the parties' Las Vegas wedding using a single shared attorney, applying Nevada law under the agreement's choice-of-law clause, and held that the homemaker wife was barred from claiming any premarital portion of her physician husband's Nevada PERS retirement account (the largest marital asset) because the PMA's clean maintenance waiver foreclosed using property division as a back-door alimony substitute.

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Sayler v. Yan Sun, 2023 MT 175, 413 Mont. 303, 536 P.3d 399

‍In a surrogacy-plus-PMA case, the Court enforced the premarital agreement against the father's argument that the surrogate had "effectively" represented the PMA was necessary to get married, reaffirming that absent incapacity, mutual mistake, fraud, misrepresentation, or other tortious conduct affecting assent, ignorance or disregard of clear contract language is no defense to enforcement.

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1. Are prenuptial agreements enforceable in Montana?

Yes. Montana adopted the Uniform Premarital Agreement Act in 1987, codified at MCA §§ 40-2-601 to 40-2-610. A prenup is enforceable if it is in writing, signed by both parties before marriage, and executed voluntarily. Montana is one of the strongest states for prenup enforceability because courts review fairness only at the time of signing — never at divorce. Changed circumstances during the marriage (job loss, wealth growth, homemaker role) cannot be used to overturn an agreement that was fair when signed. Unconscionability is decided by the judge as a matter of law, not by a jury.

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2. How much does a prenup cost in Montana?

Attorney-drafted prenups in Montana typically run $1,200–$2,400 for straightforward agreements (two W-2 earners, no business interests) and $5,000–$10,000+ for complex situations involving ranches, businesses, trusts, or multi-state property. A single attorney reviewing a draft can cost $600–$800. The national average is roughly $8,000 per couple. Online platforms like PerfectPrenup are dramatically cheaper — you get the Montana-specific template free, then pay only for attorney review.

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3. Does a Montana prenup need to be notarized?

No. MCA § 40-2-604 requires only that the agreement be in writing and signed by both parties. Notarization and witnesses are not statutory requirements. That said, notarization is strongly recommended. In Shiffman (2023), a wife successfully denied signing her PMA, and the court invalidated it in part because authenticity could not be established. Having a notary stamp eliminates forgery and coercion arguments at minimal cost.

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4. Do you need a lawyer for a Montana prenup?

No. Montana courts have explicitly enforced prenups where one spouse had no independent counsel. In Wilkes (2001), the court upheld a PMA signed by a 21-year-old with no attorney against a 62-year-old's estate. In Hutchins (2018), a prenup was enforced despite both parties using a single shared attorney. However, separate counsel for each party dramatically strengthens enforceability and is weighed heavily in voluntariness analysis. Montana courts look at the totality of circumstances — the more safeguards you stack (independent counsel, adequate review time, detailed disclosure), the harder the agreement is to challenge.

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5. Can you waive alimony in a Montana prenup?

Yes. MCA § 40-2-605(1)(d) expressly permits the modification or elimination of spousal support. The only statutory limit is MCA § 40-2-608(2): if enforcing the waiver would make one party eligible for public assistance at the time of separation or divorce, a court may require limited support — but only enough to prevent that eligibility. This is a narrow floor. Montana does not apply a "second look" at changed circumstances, fairness at divorce, or the length of the marriage when evaluating alimony waivers. Compared to states like California or Connecticut that can override waivers based on post-marriage changes, Montana's approach gives alimony waivers substantially more certainty.

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6. What can't you put in a Montana prenup?

Two hard limits: child support and child custody. MCA § 40-2-605(2) provides that a child's right to support cannot be adversely affected by a prenuptial agreement, and custody is always decided by the court at divorce based on the child's best interests. Including these provisions risks invalidating surrounding clauses. Beyond that, any term that violates Montana public policy or criminal law is unenforceable. Everything else — property division, spousal support waivers, inheritance rights, life insurance, asset management, debt allocation, choice of law — is fair game under § 40-2-605(1).

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7. How far in advance should you sign a prenup in Montana?

Montana has no statutory minimum. The Montana Supreme Court has upheld prenups signed two days before the wedding (Wilkes, 2001) and one week before (Hutchins, 2018). However, the most successful challenges involve rushed signings combined with other pressure factors — in Shirilla (2004), the court invalidated a PMA where the wife faced visa expiration, spoke limited English, and had no attorney. Our recommendation: sign 60+ days before the wedding, with each party having 2–3 weeks to review the final version. Better yet, sign before proposing. The fewer pressure factors stacked together, the harder the agreement is to challenge.

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8. Can a Montana prenup be challenged or overturned?

Yes, but the burden is steep. Under MCA § 40-2-608, the challenging party must prove either: (1) involuntary execution (coercion, duress, or undue pressure at signing), OR (2) unconscionability at signing combined with all three of the following: no fair and reasonable financial disclosure was provided, the challenging party did not sign a written waiver of disclosure, AND the challenging party lacked adequate knowledge of the other party's finances. Proving unconscionability alone is not enough — all three disclosure failures must also be shown. This conjunctive standard makes Montana one of the hardest states in which to overturn a prenup.

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9. What makes a Montana prenup unenforceable?

The most common grounds are involuntary execution and procedural failures around disclosure. Montana courts look at the totality of signing circumstances. Factors that have contributed to invalidation include: language barriers combined with immigration-timing pressure (Shirilla), inability to prove the document was actually signed by the challenging party (Shiffman), and listing assets on the disclosure schedule that did not yet exist (Shiffman). Factors that have not been enough to invalidate include: lack of independent counsel alone (Wilkes), signing days before the wedding (Wilkes, Hutchins), or one party's regret about the other's post-marriage conduct (Stout/Gollehon). Protect your agreement by ensuring both parties have counsel, sign with adequate time, provide thorough and accurate disclosure, and notarize.

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10. Does a Montana prenup protect inherited property?

Yes, but it requires explicit drafting because Montana's default rules are unusually aggressive. Under MCA § 40-4-202, Montana courts follow an "all-property" equitable distribution model — they can divide premarital assets, inherited assets, and gifts alongside marital property. Unlike the ~41 states that automatically classify inherited property as separate, Montana treats everything as divisible. A properly drafted prenup overrides this default and keeps inheritances separate. Critical: avoid commingling inherited property with marital funds during the marriage. Depositing an inheritance into a joint account or using it to improve jointly titled property weakens the prenup's protection.

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11. Why is a prenup more important in Montana than in most other states?

Two reasons. First, Montana's all-property equitable distribution model (MCA § 40-4-202) means that without a prenup, a court can divide everything you own — premarital assets, inheritances, gifts, family ranch land — regardless of when or how you acquired it. Most states automatically protect at least some premarital or inherited property; Montana does not. Second, Montana is one of the few states that still recognizes common law marriage (MCA § 40-1-403). Couples who cohabit and hold themselves out as married can become legally married without a ceremony, triggering all default property-division rules. If you own a ranch, business, or significant assets and live with a partner in Montana, you need a prenup even if you have no plans for a formal wedding.

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12. How does Montana's common law marriage recognition affect prenups?

Montana recognizes common law marriage under MCA § 40-1-403. A couple can become legally married without a license or ceremony if they are competent, mutually consent to the marriage, and confirm it by cohabitation and public repute. Under MCA § 40-2-606, a prenup signed "in contemplation of marriage" becomes effective upon marriage — including a common law marriage. This means cohabiting couples in Montana can sign a prenup before holding themselves out as married, and it will automatically activate if a court later finds a common law marriage exists. If you are cohabiting in Montana and want financial separation, sign a prenup now rather than waiting for a formal engagement.

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13. Does a Montana prenup override a will?

Generally, yes. Montana law provides default property rights for surviving spouses, including an elective share under MCA § 72-2-221 that allows a surviving spouse to claim a percentage of the augmented estate regardless of what the will says. A prenup can waive these default rights. Under MCA § 40-2-605(1)(e), parties can contract about wills, trusts, and other arrangements to carry out the agreement. If the prenup says each party waives inheritance claims against the other's estate, that waiver generally controls over a conflicting will — unless the agreement was itself unenforceable under § 40-2-608. This makes a prenup critical for blended families, second marriages, and anyone who wants to direct assets to children from a prior relationship rather than a surviving spouse.

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14. Can you change a prenup or get a postnuptial agreement in Montana?

Yes. Under MCA § 40-2-607, a prenup can be amended or revoked after marriage by a written agreement signed by both parties. No additional consideration is required — mutual agreement is enough. An oral modification is not enforceable. This written amendment is commonly called a postnuptial agreement. Montana does not have a separate postnuptial statute; postnups are governed by the same amendment provision in the UPAA. The same enforceability standards apply: the amendment must be voluntary and not unconscionable. If your financial circumstances have changed significantly since your wedding — new business, inheritance, children, career shift — a postnuptial amendment lets you update the agreement without starting over.