My friend and I invented this together… who owns what?

If you’ve ever built something with a friend, whether it’s an app, a product, a process, a “why doesn’t this exist yet?” solution—you already know the vibe. It starts with energy, late-night texts, and a shared “we’re onto something,” but then, as you get into the logistics of things, you begin to search, “My friend and I invented this together…who owns what?”

Then the uncomfortable question shows up:

“Are we both co-owners? How does this work?”

That’s not a rude question. It’s the grown-up question. And asking it early is how you keep a good partnership from turning into a lawsuit with receipts, or a falling out later down the line.

How ownership really works when two people create something together:

Inventor vs. owner: they’re not the same thing

This is the part that surprises people. Allow our firm to break it down for you in a way that’s simplified.

An inventor is the person who contributed the inventive idea—the “new” part that makes it patentable.

An owner is the person or company that holds the rights to the invention (usually through an assignment agreement).

In the U.S., patents must list the true inventors. You can’t “thank” your friend by listing them as an inventor if they didn’t actually contribute to the invention. And you can’t cut someone out just because you’re mad, or you paid for materials, or you came up with the name.

But even if you’re correctly listed as an inventor, ownership can still be transferred—often to a company, investor, or another person—if you sign an assignment (contract). That’s why paperwork matters.

What counts as a “joint inventor”:

Not everyone who helped is automatically a joint inventor.

Examples of contributions that often do qualify:

• Your friend designed a key feature that solves the problem in a new way
• You came up with the core method, and they refined it into the version that actually works
• You each contributed different essential pieces of the final invention (not just the packaging or marketing)

Examples that usually do not qualify (even if they were helpful):

• Paying for supplies or development
• Giving feedback like “make it faster” or “users would like this better”
• Doing routine coding, building, or testing without contributing to the inventive concept
• Marketing ideas, brand names, logos, or business strategy

A simple way to think about it: inventorship is about the “aha” that makes it new, not the sweat that makes it real.

If we’re joint inventors, do we automatically split everything 50/50?

Not necessarily.

People assume “we invented it together” equals “we own it equally.” But the law doesn’t work like a friendship bracelet.

If there’s no written agreement, ownership can default in ways you didn’t intend. And here’s the big landmine:

If two people jointly own a patent in the U.S., each co-owner may be able to use it, make it, sell it, and license it—without the other person’s permission—and without paying the other person a dime, unless you have an agreement that says otherwise.

Read that again. That one rule is responsible for a lot of “how did this get so ugly?” situations.

How to split ownership the smart way:

If you and your friend are building something real, you want clarity in writing while you still like each other. That doesn’t mean you don’t trust them. It means you respect the project enough to protect it.

Here are clean, common options:

Option 1: You both own it personally (with a written co-ownership agreement)
This can work early on, but it needs rules:

• Who can license it, and under what terms?
• Do both signatures have to be on deals?
• How are profits split?
• What happens if one person wants out?
• What if one person stops contributing?

Option 2: Assign it to a company you both own
This is often the best “business-ready” structure. You form an LLC or corporation and both inventors assign their rights to the entity. Then the company owns the invention, and you each own your percentage of the company.

It’s cleaner for investors, cleaner for licensing, and usually prevents the “one person goes rogue” problem.

Option 3: One person owns it, the other gets a license or a royalty
Sometimes one person is driving the business and the other wants a fair return without ongoing involvement. You can document:

• A license back to the other person
• A royalty percentage
• A buyout clause
• Milestones (for example, royalties start after sales begin)

The key is deciding this before money or attention hits the project.

Mistakes that blow up later (and they’re more common than you think):

1. Waiting until you’re “successful” to define ownership
   Nothing tests friendships like a sudden opportunity. Investors, customers, and media attention have a way of turning vague arrangements into hard feelings.
2. Mixing work, employers, and side projects
   If one of you created this on company time, using company equipment, or under an employment agreement that claims inventions—your employer may have rights. That can derail a patent or a deal fast.
3. Filing a patent with the wrong inventors (or missing one)
   Incorrect inventorship can create huge legal problems and can even make a patent unenforceable if it’s not handled properly.
4. Using a handshake deal for a business asset
   A handshake is great for ordering wings. Not for splitting ownership of an invention.
5. Publicly disclosing the invention before protecting it
   Posting online, pitching without an NDA, launching a demo—those moves can impact patent rights and negotiating leverage. Timing matters.

A practical checklist for “we invented this together”:

If you’re reading this and thinking, “Yep, that’s us,” here’s a solid next step list:

• Write down who contributed what (dates help)
• Decide: personal co-ownership or company ownership?
• Put the split in writing (ownership percentage alone is not enough)
• Include “what if we break up?” terms: buyout, exit, deadlock
• Handle assignments and confidentiality before pitching broadly
• File strategically (often a provisional patent application is a smart early step)
• Make sure inventorship is correct before anything is filed

You don’t need to be suspicious. You just need to be clear.

Overall, when friends invent together, the invention isn’t the hard part. The hard part is what happens after the invention—when real money, real risk, and real opportunity show up.

A short, well-written agreement now can save you years of stress later. And it can protect the friendship, too.

If you and a co-inventor are unsure how to split rights, how to structure ownership, or whether a patent filing could create problems, call Tucker Law at 1-800-TUCKERWINS. A quick conversation can help you avoid the kind of preventable blow-ups we see all the time.