Yes, two siblings can buy a house together on one mortgage. Fannie Mae's Selling Guide defines a borrower as any applicant, "individually or jointly," whose credit is used for qualifying. There's no marriage or family test, and a "co-borrower" is any borrower whose name isn't first on the note. Here's what most people miss: each of you is on the hook for the entire loan, whatever the deed says about who owns what.
Bank of America's 2026 Homebuyer Insights Report, released June 23, 2026, found 32% of Gen Z considering co-buying with friends or family. Its 2025 edition, released May 28, 2025, had the sibling number: 22% of Gen Z homeowners bought with a sibling, up from 12% in 2024 and 4% in 2023.
Does the lender care how you split ownership?
No. You're signing two different contracts, and the lender only reads one of them. The deed is your agreement with each other. The note is your agreement with the lender, and the uniform Fannie Mae and Freddie Mac note says: "If more than one person signs this Note, each person is fully and personally obligated to keep all of the promises made in this Note, including the promise to pay the full amount owed." A 60/40 split on the deed is a 100/100 split on the loan.
On a conventional loan, Fannie Mae requires each borrower to sign the security instrument (the deed of trust or mortgage), sign the note, and take title. FHA, under HUD Handbook 4000.1, is the same idea: every borrower and co-borrower takes title, is obligated on the note, and signs all security instruments.
Joint tenancy or tenancy in common: which one should siblings choose?
Two unmarried adults generally hold title one of two ways.
| Question | Joint tenancy with right of survivorship | Tenancy in common |
|---|---|---|
| Can the shares be unequal (60/40)? | Generally no; equal shares | Yes, any split you record |
| What happens to a share when one of you dies? | Passes to the surviving sibling automatically | Passes by will or intestacy to that sibling's heirs |
| How is it created on the deed? | Must be expressly declared; some states require more | Usually the default when the deed is silent |
Vesting varies by state, so have a real estate attorney licensed in your state draft the deed. A few examples: California, Arizona, Florida, and Washington all default a deed to two unmarried people to tenancy in common unless survivorship is expressly declared, and California defines a joint tenancy as "equal shares." Oregon abolished joint tenancy; the words "joint tenants" on an Oregon deed create a tenancy in common unless the deed clearly declares survivorship. Texas requires co-owners who want survivorship to "agree in writing," and that agreement "may not be inferred from the mere fact that property is held in joint ownership."
How does a lender qualify two siblings on one loan?
Here's how each program scores two credit files.
| Program | How two credit files become one score | Where it is written |
|---|---|---|
| Conventional, Fannie Mae Desktop Underwriter | The average of each borrower's median score. For loan casefiles created on or after November 16, 2025, DU no longer applies a fixed 620 minimum to that average; it evaluates the file's overall credit risk instead. | Selling Guide B3-5.1-01 (effective April 22, 2026); DU Version 12.0 November Update release notes |
| FHA | A minimum decision credit score is set for each borrower, then the lender selects the lowest one for the whole loan. | HUD Handbook 4000.1 II.A.1.b.ii |
| Conventional, Freddie Mac Loan Product Advisor | Freddie Mac has its own method for turning two reports into one indicator score. | Freddie Mac Guide Section 5202.1; ask your lender which method applies |
Lenders add their own floors and pricing on top, and many price off the lower score. That varies by lender, which is why I shop a sibling file across several.
For debt-to-income, Fannie Mae adds up all borrowers' monthly obligations, including the new housing payment, and divides by "total monthly income of all borrowers, to the extent the income is used to qualify." The ceilings for debt-to-income and credit are in what it takes to qualify for a mortgage.
If both of you are borrowers, the money either of you brings is borrower funds. Gift rules kick in when money comes from someone not on the loan. Fannie Mae's Selling Guide, effective February 4, 2026, allows a gift from anyone "related to the borrower by blood, marriage, adoption, or legal guardianship" with a letter signed by the donor, and FHA's gift letter is signed and dated by the donor and the borrower. More in FHA loan questions.
The FHA row above reflects Handbook 4000.1 Update 18, which HUD issued on August 12, 2026; lenders must adopt it no later than November 10, 2026.
Get both of you underwritten before you shop, together and then each alone. My post on the preapproval edge explains why.
What if only one of you is going to live there?
Then the one not moving in is a non-occupant co-borrower. Under Fannie Mae they "may or may not have an ownership interest" in the property, but they sign the note and share liability. Under FHA, the maximum loan-to-value for a non-occupying borrower transaction depends on whether the borrowers are family members, and HUD's definition includes a brother or sister. That's HUD's program rule, cited to Handbook 4000.1. The loan-to-value figures are in my guide to buying with a non-occupant co-borrower.
What does this do to the sibling who moves out first?
Say your sister moves away three years in and you take over the payment. She's still on the note. So when she applies for her own mortgage, the entire payment on your shared house shows up in her debt-to-income ratio. I call it the phantom mortgage: a payment she no longer makes, counted as if she does.
There's one door out, and it has a 12-month lock. Fannie Mae's Selling Guide, in the version effective August 5, 2026, lets a lender exclude that payment only when the sibling paying it is also obligated on the mortgage, there are no delinquencies in the most recent 12 months, and no rental income from the property is used to qualify. The proof is "the most recent 12 months' canceled checks (or bank statements)" from the paying sibling. FHA's contingent-liability rule counts the payment unless the lender documents that the other obligated party "has made 12 months of timely payments."
How does one sibling get out?
Your exit plan is a loan application you haven't filed yet.
Sell. Both of you sign, the loan gets paid off at closing, and you split the proceeds per your agreement.
Buyout by refinance. The staying sibling refinances alone, and the departing sibling's share of the equity comes out of the new loan at closing. Fannie Mae treats "buying out a co-owner pursuant to an agreement" as a limited cash-out refinance as long as the property has been jointly owned for at least 12 months and the sibling who keeps the house receives none of the proceeds, not even the small cash-back allowance (the greater of 1% of the new loan amount or $2,000) that an ordinary limited cash-out refinance permits. Under 12 months of joint ownership it's a cash-out refinance instead, though Fannie Mae waives its usual 12-month loan-age rule for a co-owner buyout. Either way the staying sibling qualifies alone; more in cash-out refinance questions.
Let me break down the math, as an illustrative example and not an offer or a rate or APR quote. Two siblings buy a $400,000 house 50/50. Five years later it appraises at $460,000 with a $340,000 balance: $120,000 of equity, $60,000 each. Say refinance costs, which vary by lender and state, run $8,000 and come off the top, $4,000 each, so the departing sibling nets about $56,000 and the staying sibling's new loan is about $404,000 ($340,000 plus $56,000 plus $8,000). That's roughly 88% of the appraised value, and they have to qualify for it alone. Redo it with your own numbers in the mortgage calculators.
Assumption or release of liability. FHA loans are assumable. The assuming borrower goes through full underwriting, and HUD releases the original borrower through form HUD-92210.1. On a conventional loan, Fannie Mae's Servicing Guide requires the servicer to find that the remaining borrower's "credit and financial capacity is acceptable" before a release.
A quitclaim deed doesn't do it. Signing your share over to your sibling moves the deed and leaves the note where it was. You still owe the lender, and the phantom mortgage follows you.
Partition, the last resort. When co-owners deadlock, either one can ask a court to partition the property, usually by ordering a sale. California's Partition of Real Property Act, effective January 1, 2023, covers any tenancy in common without a recorded partition agreement and gives the co-owner who didn't ask for a sale the right to buy the other's interest at a court-determined value. Some states, Texas and Michigan among them, have a version of the Uniform Partition of Heirs Property Act, but the Texas version covers only property a co-owner acquired from a relative.
What should your co-ownership agreement say before you close?
Have a real estate attorney licensed in your state draft it, and sign it before closing. It should cover:
- A contribution ledger: who paid what at closing, and whether that changes the split or gets repaid first at sale.
- The buyout formula: how value is set, who pays for the appraisal, how refinance costs split, and how long the buyer has to close.
- Triggers: a job move, marriage, a missed payment, disability, death, or one sibling wanting out.
- A right of first refusal before any share is offered to an outsider.
- The move-out rule: the sibling who stays pays from their own account so you can document the 12-month exclusion later.
- A default cure period and what happens after it.
- A statement that the agreement governs partition, which in some states displaces the statutory procedure.
FAQ
Who gets the mortgage interest deduction? IRS Publication 936 says that when two people other than spouses "were liable for and paid interest" on a home mortgage, each deducts the share they paid, and the one who isn't on Form 1098 attaches a statement explaining the split. Talk to your tax professional.
Does transferring my half to my sibling trigger the due-on-sale clause? Federal law doesn't protect it. The Garn-St Germain exemptions cover transfers on death, to a spouse or children, and into a living trust, and a living transfer to a sibling isn't on the list. Fannie Mae's servicing rules do exempt a transfer to a brother or sister who occupies the property on loans it owns; FHA, VA, and other investors vary, so ask the servicer in writing first. An exempt transfer still doesn't take anyone off the note.
Can one of us be self-employed? Yes. On a conventional loan, a self-employed sibling's qualifying income is what the tax returns support, often well below what the business earns after write-offs. Some Non-QM programs qualify the two of you differently; I check which ones fit before you apply. Start with the self-employed mortgage guide.
Run Both Scenarios Before You Write an Offer
Math is what I do. If you and your sibling are thinking about buying together, I'll run the numbers twice: both of you on the application, then each of you alone, so you know which exits exist before you commit. No obligation. Call or text (949) 990-6030, or schedule a call. Knowledge is power.
Disclosures: Randy Mathis, NMLS #1516760 | DRE #02236644. Lumin Lending, Inc., NMLS #2716106 | DRE #02291443. Equal Housing Opportunity. Licensed in AL, AZ, CA, CO, FL, ID, MD, MI, OR, PA, TN, TX, UT, VA, WA. This article is educational and is not a commitment to lend, a rate quote, or an APR disclosure, and it is not legal or tax advice. Title vesting, co-ownership agreements, and partition are governed by state law; consult a real estate attorney licensed in your state. Agency guidelines and lender overlays vary by lender, program, and property, change frequently, and are subject to credit approval and income and property qualification. Nothing here is a prediction or representation of approval for any borrower. All dollar figures are illustrative examples only, not an offer of credit or a representation of terms available to any borrower. Survey statistics cited are published third-party figures as of their stated dates and describe the market, not any individual application. Sources: Fannie Mae Selling Guide B2-2-01, B2-2-04, B3-5.1-01 (effective April 22, 2026), B3-6-02, B3-4.3-04 (effective February 4, 2026), B3-6-05 (effective August 5, 2026), B2-1.3-02 (effective October 8, 2025), and B2-1.3-03 (effective December 10, 2025); Fannie Mae Multistate Fixed Rate Note, Form 3200; Fannie Mae Desktop Underwriter Version 12.0 November Update release notes; Fannie Mae Servicing Guide D1-4.1-02 (effective August 13, 2025) and F-1-28 (effective March 11, 2026); Freddie Mac Seller/Servicer Guide Section 5202.1; HUD Handbook 4000.1 Update 18 (issued August 12, 2026, mandatory November 10, 2026); 12 U.S.C. 1701j-3; IRS Publication 936; California Civil Code 683 and 686 and Code of Civil Procedure 874.311 and 874.317; Arizona Revised Statutes 33-431; Florida Statutes 689.15; Revised Code of Washington 64.28.020; Oregon Revised Statutes 93.180; Texas Estates Code 111.001 and Texas Property Code 23A.002; Michigan Compiled Laws 600.3401; Bank of America Homebuyer Insights Report (2025 and 2026 editions). Information current as of September 23, 2026.
