Last Will and Testament vs. Pre-Nuptial Agreement: Which One Prevails?

Last Will and Testament vs. Pre-Nuptial Agreement: Which One Prevails?

August 11, 2025

Tanko Law Montana

Simple Answer: It depends on the language of the documents..


Prenuptial/Anti-nuptial Agreements


Generally speaking, a Pre-nuptial Agreement is an agreement that is entered into prior to marriage that delineates each person’s property and how that property is to be handled in the marriage and beyond. In Montana, these agreements are contracts that must be entered into with full disclosure and without coercion.


Prenuptial Agreements and Wills


If the terms of the Prenuptial Agreement conflict with the terms of either spouse's Last Will and Testament, a Montana probate court may choose to uphold the Agreement unless the deceased spouse's beneficiaries can show that the Agreement was created under duress, is unfair, or tended to “encourage” divorce, according to the Legal Information Institute. Montana probate courts tend to rule in favor of a Prenuptial Agreement when it appears that the Agreement was fairly negotiated and entered into with full and fair disclosure of assets and debts.


What If There Is No Will?


A Prenuptial Agreement may be used to distribute the estate if one spouse dies intestate, meaning without a will or estate plan, or if a will was later found to be invalid. Usually, the Montana probate court will apply state law to decide who receives the property left by an intestate person. However, since the Agreement is a contract made while the deceased person was alive that deals with that person's property, the court may use the Agreement to distribute the property. In this situation, the Agreement can over-ride Montana state law even if a will could not.


Specificity Matters.


A Prenuptial Agreement is more likely to take priority over a will in Montana if it contains a few specific clauses. The Agreement should state which law should be applied to interpret it, especially if it was made in a different state than Montana. Otherwise, the law in Montana will be controlled, even if that was not the law the couple had in mind when they made the will. A Prenuptial Agreement may also contain a “sunset clause”- a provision that delineates an expiration date for the Agreement. If that date has passed, the Agreement is no longer binding and the will may govern the distribution of the estate.


For more information, please contact Estate Planning Attorney Brian C. Tanko at Tanko Law Office 406-257-3711, or visit us on our website at www.tankolaw.com and Facebook at www.facebook.com/tankolaw.

Talk to a Montana Estate Planning Attorney

Brian Tanko brings over 20 years of experience as an attorney, CPA, and Certified Fraud Examiner to every estate plan. Schedule a consultation to discuss your situation.

Latest Posts


Montana Trust Laws: What You Need to Know | Tanko Law
By Tanko Law Montana May 25, 2026
Creating or administering a trust in Montana? Learn the key statutes, trustee duties, tax rules, and common mistakes, from a Montana trust attorney.
Revocable vs Irrevocable Trust: Key Differences Explained
By Tanko Law Montana May 22, 2026
Revocable vs irrevocable trust: Discover key differences, asset protection benefits, tax impact, and which trust is right for your Montana estate plan.
By Tanko Law Montana November 24, 2025
Starting a business in Montana is an exciting prospect, drawn by the state’s scenic vistas, expanding economy, and a culture that encourages entrepreneurship. From Bozeman’s tech scene to the rural revitalization of small towns, Montana’s business environment is ripe with opportunity. Naturally, this raises a crucial question for hopeful founders: Do you need a lawyer to start a business in Montana? The short answer is no—Montana law does not require entrepreneurs to hire an attorney. However, relying solely on a do-it-yourself approach can carry significant risks. Legal counsel often proves invaluable, ensuring your business is built on a solid legal foundation and helping you avoid costly missteps. The “Do-It-Yourself” Approach: Step-by-Step Guide Many entrepreneurs choose the DIY route, leveraging online resources and the state’s accessible filing systems. Here’s what the journey typically looks like: Choosing a Business Structure: Decide whether to operate as a sole proprietorship, LLC, corporation, or another entity. Each has different implications for liability, taxes, and management. Naming the Business: Select a unique name and verify its availability via the Montana Secretary of State before registering. Appointing a Registered Agent: Montana law requires every business to designate a resident agent who can accept legal documents. Filing Formation Documents: For an LLC, file Articles of Organization; for a corporation, file Articles of Incorporation—these can be submitted online. Obtaining an EIN: Secure an Employer Identification Number from the IRS for tax purposes and to open business bank accounts. Registering for Permits and Licenses: Depending on your industry and location, you may need state or local permits and licenses. DIY Resources make this process smoother: The Montana Secretary of State’s website features an easy-to-use online business portal. Free and paid templates exist for basic legal documents like operating agreements and bylaws. Business formation services (LegalZoom, ZenBusiness, etc.) offer step-by-step assistance for a fee, but these won’t provide personalized legal advice. The Hidden Dangers of Going Solo While Montana makes starting a business accessible, there are pitfalls if you proceed without professional legal guidance: Choosing the Wrong Business Structure: A mistaken selection can expose your personal assets to liability or result in unexpected tax bills. The stakes are even higher for partnerships or multi-member LLCs, where misunderstandings multiply. Legal Documentation Errors: Without a tailor-made operating agreement or bylaws, disputes among owners become more likely. Incomplete or incorrect filings can delay the start of your business or threaten its legal standing. Most importantly, you may unknowingly sign documents with significant and sometimes detrimental legal weight. Compliance Issues : Missing a single required license or failing to comply with Montana employment laws can lead to expensive fines, legal troubles, or even forced business closure. Overlooking trademark and copyright protections exposes you to intellectual property disputes down the road. The Value of an Attorney: Far More Than a Form-Filler An experienced Montana business attorney is more than just someone who files paperwork. They become a strategic partner who can: Guide You to the Right Structure : Attorneys analyze your business goals and recommend the right entity for liability protection and tax efficiency, explaining the long-term consequences of each option. Draft and Review Critical Documents: A lawyer crafts operating agreements or bylaws that reflect your business’s specific needs, making sure all paperwork aligns with state law and offers genuine protection. Proactively Manage Risk: From anticipating disputes to helping with contracts and lease agreements, legal counsel protects you from costly mistakes. As your business grows, ongoing legal advice helps you navigate changes in law, ownership, or structure. Conclusion While Montana’s pro-business climate makes DIY company formation tempting, skipping legal counsel is a gamble. Mistakes in the choice of structure, documentation, or compliance can jeopardize both your investment and personal assets. The cost of a lawyer may seem unnecessary up front, but it often saves much more by avoiding problems later. Ultimately, entrepreneurs should—at minimum—seek an initial consultation with a knowledgeable Montana business attorney. Understanding your unique risks and requirements before launching ensures your new venture is both successful and secure. If you’re looking for an expert Montana business attorney, contact Tanko Law !