By The Chipkie Team, Personal Finance Editorial Team · Last updated 18 August 2026
Buying a home with a friend, a sibling, or a partner you are not married to has moved from fringe strategy to mainstream necessity. With median home prices well beyond what a single median income supports in most metros, pooling money is often the only realistic path to ownership. But a co-buying property agreement is what separates a smart joint investment from a slow-motion legal disaster. The deed tells the county who owns the house. It says nothing about who pays the furnace bill, what happens when one of you wants out, or how an uneven down payment gets repaid.
Our experience reviewing agreements between co-owners shows the same pattern again and again: everyone is aligned on day one, and nobody has written down what happens on day 900.
Key Takeaways
- Tenants in Common is almost always the right title structure for friends, siblings, and unmarried couples, because it allows unequal ownership shares and independent inheritance rights.
- A mortgage creates joint and several liability: the lender can pursue any one co-borrower for 100% of the debt, regardless of what your private agreement says.
- Under the Fannie Mae Selling Guide (B3-4.3-15), an unsecured personal or family loan is not an acceptable source of down payment funds — it must be a documented gift or a loan secured against an asset.
- The IRS gift tax annual exclusion is $19,000 per recipient per giver in 2026, and the lifetime gift and estate exemption is $15,000,000 per individual following the One Big Beautiful Bill Act.
- A buy-sell or “shotgun” clause is the single most effective exit mechanism for co-owned real estate.
What Should a Co-Buying Property Agreement Actually Contain?
A co-buying property agreement is a private written contract between co-owners that governs contributions, ownership percentages, expenses, decision-making, and exit. It sits alongside — not inside — the deed and the mortgage. Seven terms do the heavy lifting, and skipping any one of them is where most co-ownership disputes originate.
- Ownership shares and title form. State the exact percentage each party owns and record title as Tenants in Common unless you affirmatively want survivorship.
- Capital contributions. Document every dollar of down payment, closing costs, and pre-move-in repairs, with the date and source.
- Ongoing expense split. Mortgage, property taxes, insurance, HOA dues, maintenance, and a funded reserve for capital repairs.
- Default and cure. What happens if someone misses their share of a payment — grace period, interest on the shortfall, and dilution of equity.
- Decision-making thresholds. Which choices need unanimity (selling, refinancing, taking a tenant) versus a simple majority.
- Exit mechanism. Right of first refusal, valuation method, notice period, and a buy-sell trigger.
- Death, disability, marriage, and divorce. Including a spousal waiver in community property states.
How Do You Handle Unequal Deposit Contributions Fairly?
Unequal deposit contributions are the most common source of friction between co-owners. There are three defensible ways to treat them: adjust ownership percentages to match, treat the excess as a documented loan from one owner to the other, or credit the larger contributor off the top at sale before splitting the remaining equity.
Each has different consequences:
| Approach | How it works | Watch out for |
|---|---|---|
| Adjust ownership shares | Contribute 70% of the down payment, own 70% as tenants in common | Future appreciation is split unevenly forever, even if payments become equal |
| Treat the excess as a loan | The over-contributor is repaid with interest before equity is divided | Must be papered as a real loan with a rate and schedule, or the IRS may treat it as a gift |
| Equity credit at sale | Original contributions returned first, appreciation split by agreed percentage | Needs a clear formula for what happens if the home sells at a loss |
If a parent is funding one side of the purchase, decide clearly whether it is a gift or a loan and paper it accordingly. Many families find that a properly structured written family contribution agreement prevents the awkward conversation later about whether that $60,000 was ever meant to come back.
Why Do Lenders Care Where the Down Payment Came From?
Because lenders verify the source of down payment funds, not just the balance. Under the Fannie Mae Selling Guide and FHA rules, an unsecured personal loan — including an informal loan from a parent or a co-buyer — is a prohibited source of down payment funds. This is an outright refusal, not merely a debt-to-income issue.
This trips up co-buyers constantly. The workarounds that actually pass underwriting are narrow:
- A true gift, documented with a gift letter from an eligible donor.
- A secured loan, backed by a note and a deed of trust recorded behind the first mortgage, at a reasonable rate, with the payment disclosed to the lender.
- Seasoned funds already in the borrower’s account for the lender’s required look-back period.
The gift letter trap. A gift letter states that the money is a gift with no expectation of repayment. If your family in fact expects to be repaid, signing that letter is mortgage fraud. This happens frequently and rarely with bad intent — a parent means it as a loan, a loan officer says “just call it a gift,” and everyone signs. Do not. Either genuinely forgive the money or structure it as a secured, disclosed loan.
On the tax side, per the Internal Revenue Service, the 2026 gift tax annual exclusion is $19,000 per recipient per giver — meaning two parents can give $38,000 to one child, or $76,000 to a couple, with no filing. Exceed it and you file Form 709, which does not mean tax is owed; it simply draws against the $15,000,000 lifetime exemption. If instead you structure a family loan, it must charge at least the applicable federal rate for that month to avoid imputed interest. The AFR changes monthly, so check the current published rate rather than relying on an old figure.
What Makes a Co-Ownership Exit Clause Actually Work?
A workable co-ownership exit clause defines a valuation method, a notice period, a funding deadline, and a fallback if the remaining owner cannot buy out the departing one. Without those four elements, the only remedy left is a partition action in state court — expensive, slow, and often ending in a forced sale below market.
The strongest mechanism is the shotgun clause: one owner names a price per percentage point, and the other chooses whether to buy at that price or sell at it. Because the naming party does not know which side they will end up on, they are strongly motivated to name a fair number.
Also address these commonly missed items:
- Joint and several liability. Your private buyout does not release anyone from the mortgage. Only a refinance or a lender-approved release of liability does that. Make the exit conditional on refinancing.
- The DTI anchor. A jointly held mortgage counts 100% against each borrower’s debt-to-income ratio on every future application, even if the other person makes every payment. This can block a co-owner from buying their next home.
- IRS Form 1098. The mortgage interest statement is issued under one Social Security number. Agree in writing how the deduction is split, or expect a tax-season argument.
- Community property. In California, Arizona, Texas, Nevada, Washington, Idaho, Louisiana, New Mexico, and Wisconsin, a co-owner’s future spouse may acquire an interest. Include a no-spouse-claim clause and a spousal acknowledgment.
When buying with friends, ownership shares should also anticipate one party wanting to rent out their room, move a partner in, or stop occupying entirely. Spell out whether occupancy affects the expense split.
Is a co-buying agreement legally enforceable?
Yes. A written co-ownership agreement is an ordinary contract, enforceable in state court like any other. Statutes of limitation on written contracts range from roughly four to ten years depending on the state, which is another reason a signed, dated document beats a text thread or a handshake.
Should we take title as joint tenants or tenants in common?
Tenants in Common suits nearly all friends, siblings, and unmarried co-buyers. It permits unequal ownership percentages and lets each owner leave their share to whomever they choose. Joint tenancy forces survivorship — if one owner dies, their share passes automatically to the co-owner, potentially disinheriting their family.
What if one co-owner stops paying the mortgage?
The lender will pursue whoever can pay, because liability is joint and several. Your agreement should let the paying owner cover the shortfall, charge interest on it, and either recover it at sale or convert it into additional equity. Include a forced-sale trigger after a defined period of default.
Do we need a lawyer, or is a template enough?
A well-drafted template covers the standard terms cleanly and is far better than nothing. Bring in a real estate attorney when the deal involves an entity, a trust, a commercial element, or a state-specific issue such as a community property waiver or a recorded deed of trust securing an internal loan.
What Should You Do Before You Sign Anything?
Handle the paperwork in the right order. Confirm your down payment sources are acceptable to the lender before you make an offer. Agree ownership percentages before you sign the purchase contract. Sign the co-ownership agreement before closing, not after. Buy an owner’s title insurance policy — it protects against defects in the chain of title that the escrow search may not reveal, and it is a one-time premium. The Consumer Financial Protection Bureau publishes plain-language guides on closing costs and title products worth reading before your closing disclosure lands.
If part of your funding is a loan between family members rather than a gift, paper it properly and separately — our guide to drafting a loan agreement that protects both borrower and lender walks through rate, schedule, and security. And if you want to see how documentation is reshaping joint purchases, read more on technology in co-buying property.
Co-ownership works beautifully when the boring questions are answered in advance and terribly when they are not. Put the money terms in writing while everyone still likes each other — create your co-ownership loan agreement with Chipkie in minutes and give your joint purchase the paper trail it deserves.
Disclaimer: The information provided in this article is for informational purposes only and should not be considered financial or legal advice. Laws and lending criteria vary significantly between states. We always recommend consulting with a qualified real estate attorney and financial advisor before entering into a property purchase or financial arrangement with another party.
