Short answer: A business one spouse owned before the marriage generally starts as that spouse’s separate property in a Utah divorce. The fight is usually over appreciation during the marriage. Growth from marital labor, or from marital funds put into the business, can be marital, and the court must isolate that marital portion rather than divide the whole business.
Owning a business before the marriage feels like an answer. If you started the company years before you got married, you know it is yours. And in one important sense, Utah law agrees with you. A premarital business is presumptively separate property.
But that is not the whole answer, and treating it as one is a common and expensive mistake. The business itself may remain separate, but the value it built during the marriage often does not. In a Utah divorce involving a closely held business that predates the marriage, the real fight is almost never about the pre-marriage entity. It is about the appreciation. How much of what the business became during the marriage belongs to the marital estate.
Understanding that distinction, and the analytical work that separates the marital portion of appreciation from the separate baseline, is where high-asset divorces involving premarital businesses are won and lost.
The Starting Point: The Entity Stays Separate
Property owned before the marriage is presumptively separate under long-standing Utah law tracing back to the Utah Supreme Court's decision in Mortensen v. Mortensen, 760 P.2d 304 (Utah 1988). That presumption applies to a business as much as to any other asset. If the business existed before the marriage and no exception applies, the underlying entity remains separate at divorce.
The exceptions that can move the entity itself onto the marital side of the ledger (commingling that destroys traceability, retitling, and the contribution exception) apply to businesses as they do to other property. Those exceptions are addressed generally in a companion article on Utah commingling and separate-to-marital pathways. This article focuses on the more common battleground in business-owner divorce: not the entity itself, but the appreciation in its value during the marriage.
Appreciation: The Analysis That Actually Drives These Cases
The starting rule on appreciation is straightforward. Appreciation on separate property presumptively follows the asset. If the business is separate, the appreciation is separate, unless an exception applies.
The reality behind that rule is more nuanced. Utah courts distinguish between two very different kinds of appreciation:
• Passive appreciation. Growth driven by market conditions, inflation, or other forces external to the parties. Passive appreciation follows the underlying asset. If the business is separate, its passive appreciation remains separate.
• Active appreciation. Growth driven by marital effort or by the investment of marital resources. Active appreciation may be marital even where the underlying entity is separate.
This distinction is the analytical spine of a premarital business case. The Utah Court of Appeals reinforced it in Thorup v. Thorup, 554 P.3d 329 (Utah Ct. App. 2024), where the court laid out the framework in careful detail and emphasized that specific findings are required before a court can treat appreciation as anything other than separate. A trial court cannot simply sweep the whole appreciation into the marital estate without doing the work of identifying which portion is which.
The Two Ways Appreciation Becomes Marital
Working from the framework, appreciation on a premarital business becomes marital in one of two ways:
First: Active Appreciation From Marital Labor
If the owner-spouse worked in the business during the marriage, that marital labor is a marital contribution. Any growth in the business attributable to that marital effort is active appreciation and is on the marital side of the ledger.
This is a bigger point than it may appear. For most closely held business owners, the labor they invested in the business during the marriage is a substantial component of what the business became. The person who worked sixty or eighty hours a week during the marriage to grow the company is putting marital effort into a separate asset every one of those hours. The value that effort produced is marital, even if the underlying entity remains separate.
Owner-spouses often resist this framing and try to characterize business growth as passive. In a service business, a professional practice, or any operation whose value tracks the owner's work, that characterization rarely holds up. The court is looking at reality, and the reality of most closely held businesses is that they grew because the owner ran them, not because market forces lifted them independently.
Passive appreciation still exists. Real estate that appreciates because the surrounding neighborhood did. A holding company whose value tracks a broader index. Investment assets on the balance sheet that appreciated on their own. These pieces can be identified and preserved as separate. But the operating value of a closely held business built and run by the owner during the marriage is a much harder argument to keep on the passive side.
Second: The Contribution Exception
The contribution exception provides the primary path for a non-owner spouse to reach the appreciation in the other spouse's separate business, independent of the marital-labor analysis. As summarized in Brown v. Brown, 476 P.3d 554 (Utah Ct. App. 2020), the contribution exception is generally satisfied in one of three ways:
• Prudent investment of effort or resources that increased the value of the separate asset
• Marital funds or marital debt used for the benefit of the separate asset
• The non-owner spouse working in the other spouse's business without pay or below a market wage
Each of these has application to a premarital business, but the third is the one that arises most often and generates the sharpest disputes.
The Unpaid Spousal Labor Path
Where a non-owner spouse worked in the other spouse's business without pay, or accepted a below-market wage, the labor is treated as a contribution to the growth of the business. In Dunn v. Dunn, 802 P.2d 1314 (Utah Ct. App. 1990), the court treated a wife's unpaid bookkeeping and secretarial work, and her running of the household while her husband worked 60 to 70 hours a week, as a contribution to the growth of a professional corporation formed during the marriage. Courts apply the same reasoning when a spouse claims a share of a premarital business's growth.
The Dunn framing has held up. But it does not extend to every kind of involvement, and this is where owner-spouses fight back.
The limiting case is Lindsey v. Lindsey, 392 P.3d 968 (Utah Ct. App. 2017). There, the non-owner spouse's household responsibilities and her intermittent help entertaining and hosting business clients did not satisfy the contribution exception. The court concluded that indirect or intermittent support, without direct operational involvement or a financial contribution to the separate business, was insufficient to convert it. Lindsey is the case an owner-spouse will point to in any contribution fight where the non-owner spouse's involvement was general marriage support rather than direct business work.
Overcoming Lindsey requires evidence of direct, substantial, operational work in the business. That means specific roles, documented hours, identifiable responsibilities, and third-party corroboration. It rarely means a general narrative of having supported the business over the years.
Corroboration matters as much as the underlying facts. Stephenson v. Stephenson, 580 P.3d 389 (Utah Ct. App. 2025), shows that a spouse seeking credit for their own labor needs corroboration and evidence of a reasonable rate. Self-compiled trackers or after-the-fact estimates rarely carry the burden on their own. Testimony from people who observed the work, contemporaneous records of the role, and a defensible valuation of the labor are what move the analysis in front of a Utah court.
Marital Funds Flowing Into the Business
The second contribution path is often the cleanest one when the facts support it. If marital funds or marital debt were used for the benefit of the separate business, that infusion is itself a marital contribution and can support treating the resulting value as marital. The Court of Appeals worked through this in Keiter v. Keiter, 235 P.3d 782 (Utah Ct. App. 2010). There, the owner-spouse had run business and personal income through commingled accounts, and marital funds from those accounts were then used to acquire and improve otherwise-separate real estate. The court upheld the marital character of the value but remanded to preserve the demonstrated premarital baseline.
The same principle applies to a business. Where marital funds went into the business during the marriage (whether for expansion, capital improvements, working capital, or debt service on business obligations), the argument is that the marital estate acquired an equitable interest in the resulting value. The tracing is the fight. Owner-spouses will argue that the funds came from the business itself. Non-owner spouses will argue that once income and personal funds were run through the same accounts, the character of what flowed into the business became marital under the Keiter framework.
The Owner's Shield: One-Directional Flow
Not every fund movement between the business and the family works against the owner-spouse. Brown v. Brown held that where money flowed only in one direction, out of the separate business into personal and joint accounts, and never back in, the business itself did not lose its separate character. Using separate business income for family living expenses is not by itself commingling that converts the underlying business.
This is the owner-spouse's argument in most premarital-business cases. Yes, the business distributed money that supported the family. No, the family did not put money back into the business. Therefore the business remains separate. Where the facts genuinely support this framing, it is a strong defense.
The recent case law has reinforced the direction-of-flow point. In Krajeski v. Krajeski, 2025 UT App 19, 565 P.3d 544 (Utah Ct. App. 2025), the Court of Appeals reversed a trial court's finding of commingling and clarified that reduced owner draws from a premarital LLC business account did not convert the account. Distributions reported on the parties' joint tax returns were not relevant to whether the underlying business was marital. And distributions from separate accounts to fund marital expenses did not create backflow that transformed the separate accounts. Where flow was consistently out, the underlying entity remained separate.
The practical implication is that the owner-spouse needs to be able to show the flow direction with actual records, and the non-owner spouse needs to look hard for the reverse: money going into the business, not just coming out of it. That reverse flow is where the contribution and commingling arguments live.
Isolating the Marital Portion, Not the Whole Entity
One of the most important disciplining principles in this area of the law is that even when appreciation is marital, the court must isolate the marital portion rather than sweep the entire value of the business into the marital estate. Thorup frames this explicitly. Findings are required. The court cannot move the whole entity based on generalized conclusions about marital effort or contribution. And Keiter confirms that a demonstrated premarital baseline has to be preserved and subtracted before the marital portion is divided.
This principle shapes the analytical work these cases require. It is not enough for a non-owner spouse to establish that some appreciation is marital. Someone has to identify the pre-marriage value of the business, calculate the current value, isolate the growth attributable to active appreciation and to marital contributions, and present that analysis in a form the court can accept. This is the work of a credentialed business appraiser, and it is why serious high-asset divorce cases almost always involve expert testimony on valuation.
For owner-spouses, this principle is protective. It means the entity's premarital baseline can and should be preserved. For non-owner spouses, it means the analytical work is required. Sweeping conclusions about the business having grown during the marriage will not carry the day. Specific findings, tied to specific components of value, will.
Who Bears the Burden
In Sandusky v. Sandusky, 417 P.3d 634 (Utah Ct. App. 2018), the Court of Appeals affirmed a finding that an account the husband said he brought into the marriage was marital, because the funds had been commingled and not kept apart. The spouse claiming separate property is the one who needs the records. Applied to a premarital business, this means the owner-spouse who wants to preserve the entity and the passive-appreciation portion of its value has the burden of producing records that support the separateness claim. Bank statements, general ledger, tax returns, and CPA workpapers all become central. Where these records do not exist or cannot be produced, the argument for separateness weakens.
This is a structural incentive built into Utah law. It rewards owner-spouses who have kept clean records and punishes owner-spouses who have not. It also means that a non-owner spouse who pushes for full production of the business records is not just fishing. The records are the evidentiary battleground on which the separateness claim rises or falls.
Strategic Implications
If you own the premarital business. Do not assume the pre-marriage ownership settles the question. It settles a piece of it, but the appreciation analysis is where these cases actually get decided. Preserve the records that support your baseline. Distinguish, with expert help, between passive appreciation you can defend as separate and active appreciation that will likely be treated as marital. If the facts support the Brown one-directional-flow argument, develop it. And on the contribution question, be ready to meet the direct-operational-labor claim head-on rather than assuming Lindsey wins the day for you.
If your spouse owns the premarital business. The threshold ownership fact is often the easiest thing to concede. The appreciation analysis is where the value moves. Build the record on marital labor (both your spouse's work during the marriage and any direct operational contribution of your own), on any marital funds that flowed into the business, and on the categorization of business growth as active rather than passive. Do not settle for the label "separate" applied to the entity as a whole without pushing into what that entity became during the marriage.
For both spouses. This is an area where expert analysis pays for itself. A credentialed business appraiser who can isolate the pre-marriage baseline, identify the active-appreciation portion, and defend the assumptions under cross-examination is generally more valuable than any amount of lay argument on the same topics. The framework requires isolation, and isolation requires expertise.
Frequently Asked Questions
Is a business I owned before marriage protected in a Utah divorce?
The business itself generally stays separate, but the rule is not absolute, and growth during the marriage can be partly marital.
When does appreciation on a premarital business become marital?
When the growth comes from either spouse’s work in the business during the marriage, or from marital funds or debt used for the business.
How much of the business can be divided?
Only the marital portion. Even when some appreciation is marital, the court must separate it from the premarital value and passive growth.
Who has to prove what is separate?
The spouse claiming property is separate carries the practical burden of tracing it with records.
If Your Divorce Involves a Business That Predates the Marriage, Start the Analysis Early
Utah's framework for premarital businesses is well developed, but it is analytical and it is fact-intensive. The records that will matter, the valuation work that will drive the outcome, and the expert testimony that will present it all take time to build. In a business-owner divorce, the party who understands the framework and starts the analytical work first usually has the strongest position when the case actually gets decided.
Jeremy Miller handles high-asset divorce cases throughout Utah involving premarital businesses, closely held companies, and the complex characterization and appreciation issues these cases turn on. He works with credentialed business appraisers to build the analytical record that separates the premarital baseline from the marital appreciation and to present that record in a form Utah courts will act on.
If your divorce involves a business that one of you owned before the marriage, contact Jeremy Miller at Pearson Butler to discuss how these principles are likely to apply.