What's a Co-ownership Agreement & How to Create One

Learn how a co-ownership agreement can protect your home, relationships, and financial interests in shared homeownership.

Published on
September 15, 2020
Updated on
May 8, 2024
What's a Co-ownership Agreement & How to Create One
Written by:
Pam Hughes
Pam Hughes
Forty years of experience across finance, real estate, insurance, and construction. Committed to personal empowerment through financial education. Best friends with a small dog known as Francis.
Matt Holmes
Matt Holmes
Planned a career in rock & roll, ended up studying economics and working in finance. Started CoBuy with my mom when we struggled to navigate all the moving parts.
Team CoBuy
Team CoBuy
CoBuy simplifies shared homeownership. Homeownership wasn't designed for friends, family members, and unmarried couples. So we're fixing it.

• Home co-owners need agreements

• Agreements reflect decisions and define terms, structure, management

• Co-ownership Agreement is a living document, not fill-in-the-blank job

• Memorandum of Agreement is secondary document to file with your County

• If created, executed, updated properly, agreements are legally-binding

Co-own a home? You need to create and manage a co-ownership agreement. It lays down the rules of co-ownership and evolves with your circumstances.

But its value isn’t always appreciated. To build wealth, protect , and future-proof your co-investment is more science than art.

Here's what we'll cover:

What is a co-ownership agreement?

A co-ownership agreement is a legal document that outlines the details of joint ownership and management of a particular property between two or more individuals.

An agreement sets the terms, structure, and management for joint homeownership, associating co-owners and their determinations to a specific property. It's more than just a document—it's the backbone of your co-ownership, adaptable to your needs and expectations.

Without a forward-looking agreement, unexpected changes could force outcomes you never intended. A well-crafted agreement prevents misunderstandings, setting clear roles, rights, and responsibilities for all parties. It also creates a framework for the day-to-day management of the co-ownership arrangement.

Who needs a co-ownership agreement?

Anyone co-investing in a property with friends, family, or a partner. Much like a business partnership, you're pooling resources, cooperating for shared interests, and sharing risks and rewards. A written agreement is your roadmap for success. When properly designed and executed, it also acts as a legally-binding contract.

Why do we need a co-ownership agreement?

Three key elements make co-ownership successful: planning, structure, and management. A written agreement is the foundation. It supports healthy relations, smooth sailing, and return on investment. 

1. Streamline operations

An agreement details roles, rights, and responsibilities, making management smoother. It acts as a source of truth that prevents misunderstandings and creates non-repudiation.

2. Prevent conflict

The agreement establishes clear expectations, including expense distribution, property use, and decision-making procedures. This roadmap helps to pre-empt potential disputes and provides a mechanism for resolution, protecting relationships, and stability.

3. Protect against risk

Co-owners don't have the same legal or tax protections as married couples. An agreement provides a legal framework to safeguard co-owners' rights and interests.

4. Limit financial exposure

Co-owners often jointly finance their property, making them equally liable for debt repayment. A comprehensive agreement can protect co-owners from financial mishaps.

5. Simplify the exit

Every co-ownership will eventually dissolve. Developing an exit strategy and documenting it in the agreement can make this process less stressful and expensive.

What does a co-ownership agreement cover?

The content and format of the agreement depend on your situation, preferences, and governing law.


In most cases, you should include:

  • Participants
  • Occupancy
  • Property description (must include a proper Legal Description)
  • How you hold Title to the property
  • Details of the home purchase
  • Mortgage Information
  • Ownership structure and individual ownership percentages
  • Individual contributions (financial capital contributions and non-financial contributions)
  • Roles, rights, and responsibilities
  • Expense allocations (recurring, non-recurring expenses, emergency)
  • Mechanics of payment
  • Maintenance and repair management
  • Decision-making
  • Dispute resolution
  • Contingency planning
  • Documentation management plan
  • Exit strategy

Some co-owners prefer to get more granular than others. The best agreements are those you all create together and commit to.

⚠️ Heads up!

How you hold Title to the property impacts the structure and composition of your co-ownership agreement. It also affects decision-making around ownership structure.

Many co-owners choose Tenants in Common (TIC) or Joint Tenants with Right of Survivorship (JTROS). In contrast, a Limited Liability Company (LLC) is generally better suited for investors managing a real estate portfolio.
CoBuy helps you create, digitally sign, and modify tailored Co-ownership Agreements from anywhere, anytime.

Other elements

In addition to the basic components, be sure to include:

➡️ Definitions and provisions: Define key terms and conditions within your agreement to prevent misunderstandings and establish clarity.

➡️ Governing law: Specify which state’s law will govern the agreement, which generally corresponds to the state where the property lives.

➡️ Written notice: Outline how formal notices, like changes to the agreement or key decisions, should be communicated. You should identify the method (e.g., email, certified mail) and the timeframe for a response (e.g., 30 days).

➡️ Review and update schedule: Treat your co-ownership agreement as a living document. Schedule regular reviews to make sure it stays up-to-date with your current situation.

➡️ Co-owner contact information: Include current contact information to ensure clear lines of communication.

How to make it official

On its own, a printed document or PDF ain’t worth much. Follow these steps to execute your agreement:

  1. Review and agree: Ensure all co-owners thoroughly review the agreement, understand all provisions, and agree to them. Address and clarify any areas of doubt.
  1. Sign and date: Each co-owner should sign and date the agreement initially and every time it is updated
  1. Witness, notarize, or digitally sign: This adds an extra layer of legitimacy to the process.
  1. Create a Memorandum of Agreement: This is a shorter, more concise document that outlines the basic terms of the co-ownership. It doesn't include all the agreement details but serves as a public record of the arrangement.
  1. Record your Memorandum of Agreement: Submit or deliver your Memorandum of Agreement to your local County’s recording office to officially record it on the public register. This ensures the agreement is recognized as a matter of public record and establishes constructive notice. Be sure to keep a copy of the filed Memorandum for your records.

Formalizing your co-ownership agreement is essential to protecting your rights and interests as a co-owner. This process helps ensure the agreement is legally binding and practically useful.

Co-owners need agreements: a Co-ownership Agreement and a Memorandum of Agreement.
Most co-owners don't know about the Memorandum of Agreement. It's a shorter document that you create, sign, and execute just like the Co-ownership Agreement. When you file the MOA at your local County recording office, it lets the world know your Co-ownership Agreement exists without publicly exposing all the details.

Updating your agreement

Your co-ownership agreement is a living document. It should evolve as your circumstances, goals, and the property itself change. Regular updates to your agreement can help you maintain harmony, protect your investment, and ensure the agreement continues to serve its purpose. Here are some key considerations:

✍️ Life developments

Significant events like marriage, childbirth, job changes, financial changes, or the death of a co-owner may require updates to your agreement. Any time a co-owner's circumstances change, review your agreement.

✍️ Asset or liability changes

If you decide to change ownership structure, modify individual ownership interests, refinance, or take on additional debt related to the property, you should update your agreement.

✍️ Property modifications

Changes to the property, such as significant renovations or new features, might warrant updates to your agreement. This is particularly true if these changes affect the use of the property or the financial contributions of the co-owners.

✍️ Conflicts

If conflicts arise between co-owners, you may want to update the agreement to better manage these disputes in the future. This could involve clarifying roles, responsibilities, or decision-making procedures.

✍️ Legal landscape evolution

Stay informed about any changes in property, tax, or co-ownership laws that might affect your agreement. If laws change, update your agreement to stay compliant.

It is important to update your co-ownership agreement regularly to ensure it remains a valuable tool and does not become outdated. All co-owners should agree upon, sign, and date all updates.

✍️ Periodic reviews

Set a schedule to review your agreement regularly: quarterly, every six months, or annually. Regular reviews ensure that your agreement stays up-to-date with everyone's current situation and expectations.

Diagram shows how a co-ownership agreement is a living document.  Document icon is centered, with the stages of the cycle and arrows circling it: engage, align, agree, formalize.


Your co-ownership agreement is a living document that reflects dynamic decisions and consensus between co-owners. It’s not a birth certificate. It’s your foundation, and you get out what you put in. It must be complete, authentic, and up-to-date to be effective and enforceable.

Think about the following as you co-create an agreement.

🔐 Secure

Your agreement should be tamper-proof wherever you decide to store it. A physical copy in your drawer or a digital copy in a shared Google Drive folder falls short. Your largest asset, home, and relationship(s) are on the line. Think like a Swiss bank.

🔑 Accessible

Make sure each co-owner has clear and easy access to all versions of the agreement.

🪄 Easy to modify

Life changes, family situations change, and jobs change. Birth, death, coupling, breakup, divorce, and illness are all possible, as are changes to your financial affairs. As circumstances evolve, so should your agreement.

🔢 Versioned

Track all changes to your agreement. A stale agreement is like a used pull tab—no good. It’s not just for cases of conflict: IRS audits, external legal challenges, or the death of a co-owner could all require details of change history.

✅ Verifiable

An agreement is only as good as its ability to be verified. If you can't prove that it's authentic, updated, and executed, it's worthless. A scanned PDF with scribbled signatures could be challenged in court, probate, or an audit.

Check out our blog post on how we use blockchain to help co-owners solve these challenges.

Common pitfalls to avoid

⚠️ Focusing on the output over the process

An agreement is an output—a few pieces of paper or a PDF, neither of which are inherently valuable. The usefulness of a co-ownership agreement stems from the dynamic decision-making and consensus between co-owners that it represents. 

Too often, we see co-owners focus on ticking the box. But it’s not about creating a contract so you can take your granny to court if something goes wrong! It’s about making informed decisions and getting on the same page regarding your largest asset and home. Co-creating and maintaining a co-ownership agreement helps you avoid conflict and protect the interests of everyone involved in various situations, even those that don't involve a disagreement between co-owners.

⚠️ Putting it off

Many co-owners invest more time (and money) in Netflix than planning, structuring, and managing their most important asset. An agreement isn’t a lawyer, and it can’t automatically rescue you when sh** hits the fan. 

⚠️ Neglecting it all together

Friends, family, and loved ones are not immune to risk in joint homeownership. The strength of your relationship(s) isn’t a substitute for a proper agreement: it's a great reason to take it seriously! Your home, relationship(s), and financial investment are worth protecting.

Pro tips

• Start early

The earlier, the better. You’ll tease out hairy issues before they become problems, save time and money, and gain peace of mind.

• Think about the big picture

An agreement is an artifact that ties together the many moving parts involved in co-ownership. The usefulness depends on it being accurate, current, and comprehensive. 

• Formalize your agreement

Not documented? It didn’t happen. Not executed? It didn’t happen.

• Keep your agreement up-to-date

Treat your agreement as dynamic, because it is. The return on investment to actively managing co-ownership versus posting on social media, zombie scrolling, and fantasy football? Potentially hundreds of thousands of dollars.

💡The terms you set in your agreement are a backstop. If things go well, you can remove the training wheels. If things don’t go well, you’ll be glad you set up guardrails.

Frequently asked questions

Can’t we just use a templated document?

A co-ownership agreement is not a fill-in-the-blank job. It’s the product of dynamic decision-making between two or more parties who co-invest and co-own a home. A template can't provide guidance or structure decision-making around complex issues. A templated document is a one-size-fits-all approach will likely fail tests of specificity, completeness, and enforceability.

Imagine you co-own a $750,000 home, and the sh** hits the fan. How would you feel about depending on a $30 template? What if it ends up setting you back $30,000 when someone a co-owner can’t pay, there’s a disagreement, someone dies, it’s time to sell, or another curve ball comes your way? Like most things in life: you get what you pay for.

Do we need an attorney?

You don’t need an attorney to craft a legally binding contract for joint homeownership. 

At $500+ per hour, an attorney is an expensive option. An attorney may also lack context into interpersonal, financial, and practical considerations around co-ownership. If you choose this route, select an attorney with experience in residential real estate and co-ownership. Also, remember that you’re paying for a one-off, static document.

How do we update our agreement?

Subscribe to Shared Homeowner OS™? From the dashboard, navigate to your Co-ownership Agreement, choose the section you want to update, and make changes with a few taps. Once all co-owners have agreed, you can digitally sign to re-execute your agreement. It will automatically be recorded to the blockchain with a refreshed Certificate of Completion and can be accessed, downloaded, or shared anytime from your Document Vault.

Otherwise, your best bet is to contact the attorney who helped you create your initial agreement.

Need help with your Co-ownership Agreement? Meet Shared Homeowner OS™

We've clocked over 34,000 hours cracking co-ownership since 2016 and worked with thousands of co-buyers and co-owners.

With our new app, Shared Homeowner OS™, it's easy to plan, structure, and manage home co-ownership.

🤝 Streamline decisions
⚖️ Define ownership interests
📝 Co-create custom agreements—fast (or not)
✍️ Digitally sign from anywhere
🔐 Secure docs and records
🚪 Plan your exit strategy
⚡️ Update anytime with a few taps

One app to put you and your co-owners in control.

Eliminate guesswork, avoid conflict, save thousands on legal fees, and cut 120 hours of admin a year.

Learn more here and join the beta waitlist.

Quote from Louise Machinist, Author of the book 'My House, Our House', that reads "We need state of the art co-owner agreements...that are simple and adaptable...".

Check out our other posts:

How to split ownership of a home

Documentation in co-ownership

Exit strategies

The 3 stages of shared homeownership

Ultimate guide to shared homeownership