How do we figure out a fair buyout price for my fiancee's brother's share of the house?

I’d start by getting everyone to agree on an independent appraiser before negotiating a buyout number. That $550,000–$650,000 estimate leaves a lot of room for disagreement. The starting calculation is his share of the equity after the mortgage is accounted for. Assuming the debt and equity are allocated in the same proportions as ownership, with a $420,000 mortgage: At $550,000, his 49% share would be about $63,700. At $600,000, it would be about $88,200. At $650,000, it would be about $112,700. Those are starting figures, before other liens, actual closing costs, or any justified adjustments between the owners. I’d be cautious about using a higher hypothetical value to pay him for future appreciation. Prices could rise, but they could also fall. You might decide an additional payment is worthwhile to reach an agreement and move forward, but identify it separately as a negotiated premium. That lets you see exactly how much you’re paying above the current equity calculation. An appraisal also won’t obligate him to accept a voluntary buyout. Before settling on a price, contact the current mortgage servicer about keeping that rate, releasing any departing borrower from the loan, and how you would fund the buyout. Transferring ownership doesn’t automatically remove someone’s mortgage responsibility, and you shouldn’t assume the existing loan can stay unchanged. With three owners and disagreements about payments and occupancy, I’d bring in a Utah real estate attorney early. Have them review the deed, any ownership agreement, and records of who paid what. Don’t automatically deduct back rent or credit every mortgage payment without that review. The aunt’s 1% needs an explicit decision too: does she remain an owner, or does she agree to a buyout? A neutral mediator may help everyone reach terms. Put the price, financing, ownership changes, and brother’s move-out date in writing. If you’re contributing buyout money personally, document what ownership interest you receive as well.

An official appraisal is the easiest and most official way to accomplish this. Keith Jean-Pierre Managing Principal The Dapper Agents Real Estate Operations in ALL 50 States

Isla, the number you are looking for is not 49 percent of the house. It is 49 percent of the equity, and getting the two sides to agree on which figure they are talking about is most of this negotiation. Run it plainly. Agree on a fair market value, subtract the 420k payoff, and that is the equity. At 600k, the equity is 180k and his half share of that is about 88k. At 650k with no deductions, he gets about 113k. Your brother-in-law-to-be is going to argue the high end of your range. You are going to argue the low end. The 25k gap between those two positions is the actual conversation, and it is worth paying for a real appraisal rather than trading screenshots of online estimates. Two things move that number your way, and both are worth pricing out before you make an offer. First, the money already spent. You have been covering half the mortgage while he has lived there rent free. In a partition accounting, a court can credit a co-owner who paid more than their share of the mortgage, taxes and insurance, and in some circumstances can charge an occupying co-owner for the reasonable rental value of their exclusive use. I am a real estate professional and not an attorney, so have a Utah real estate attorney tell you what those credits are actually worth in your facts. Even a rough number changes the tone of the conversation. Second, the leverage nobody has mentioned yet. Under Utah Code 78B-6-1201, any co-owner can file a partition action, and if the property cannot be split the court can order it sold. That runs both directions. He can force a sale on you, and you can force one on him. Most people negotiating a buyout do not know this, and the moment everyone understands that a judge can put the house on the market, the positions get reasonable, because a court-ordered sale is worse for all three of you than any deal you would sign today. If these interests came through an inheritance, look specifically at Utah's Uniform Partition of Heirs' Property Act, Title 78B Chapter 6 Part 12a, which requires a court-ordered appraisal and gives the other co-owners a buyout right before any sale. That process is friendlier to the people who want to keep the house. Now the part that will cost you the most money if you get it wrong. Do not fund this buyout with a cash-out refinance. That sub-4 percent loan is the single most valuable asset in this deal. Freddie Mac's survey had the 30-year fixed at 6.65 percent for the week of August 20, 2026. Refinancing 420k from under 4 to the mid 6s adds roughly 700 to 800 dollars a month for the next thirty years, which over time dwarfs the entire buyout amount. Look instead at a home equity line or a fixed second lien that sits behind the existing first and leaves it alone. The rate on the second will be higher, but it is a rate on 90k, not on 510k. Two questions for your lender in writing before you do anything: is the existing loan assumable, and does removing a borrower or transferring his interest trigger the due-on-sale clause. FHA and VA loans are generally assumable with lender approval and conventional loans generally are not. Some family transfers are protected from due-on-sale under the Garn-St Germain Act, but a sibling buyout is not automatically one of them, so get the answer on paper. One more thing that is easy to miss. The aunt's 1 percent is not a rounding error. She has to sign the deed, and at 50 and 49 she is the swing vote on anything requiring a majority. Talk to her before you talk numbers with your brother. I work with buyers and sellers across Los Angeles and the South Bay, so Utah County is not my market, but this structure comes up constantly and the mistakes are the same everywhere. If it would help, I am glad to point you toward a strong agent in the Provo area, and I would put a Utah real estate attorney ahead of the agent in the batting order on this one. My name is Zoltan Peresztegi and you are welcome to reach out either way. Zoltan

Isla, I would start with an independent appraisal and today's market value, then calculate the current equity, not a hypothetical future value. With approximately $420,000 owed, the numbers would look roughly like this: At a $550,000 value, equity is $130,000, and the brother’s 49% share is about $63,700. At a $600,000 value, equity is $180,000, and his share is about $88,200. At a $650,000 value, equity is $230,000, and his share is about $112,700. The aunt's 1% would be $1,800 at a value of $600,000. I would be careful about paying the brother extra for possible future appreciation. Appreciation isn't guaranteed. If you choose to pay a premium because he doesn't want to sell, treat that as a negotiated incentive, not part of the basic buyout calculation. Because the family members disagree and the brother has been living there rent-free while others have contributed toward expenses, I would also have a Utah real estate attorney review the ownership, payments, and proposed buyout before anyone signs anything. Brenda Ashby | REALTOR® | JohnHart Real Estate | DRE License # 01700249

I’d start with the current fair market value, ideally based on an appraisal or recent comparable sales. Then calculate the brother’s 49% share of the equity after subtracting the remaining mortgage. I’d be cautious about paying extra based on “future appreciation” you’d be taking on that future risk once you buy him out. Also, make sure the aunt’s 1% ownership and the mortgage are addressed. An appraisal and a real estate attorney or title company can help make sure everything is handled fairly.