The cofounder prenup: Money questions to settle before the first wire hits

Starting a company with someone you trust can feel effortless at first. You’re aligned on the idea, feeling excited about what you’re building together, and running on momentum. Talking about money can feel awkward, overly formal, or unnecessary — especially if you’re friends, former colleagues, or long-time collaborators.

But here’s the truth most cofounders learn the hard way: Startups don’t usually fall apart because the product fails. They fall apart because expectations were never aligned about money, risk, and what happens when things get hard.

A “cofounder prenup” creates early clarity. It’s a set of honest, upfront conversations that help you protect your relationship, the company, and yourselves before capital, equity, or stress complicate everything. The goal is simply to ensure no one is silently carrying assumptions that could later turn into resentment.

So, before that first payment hits your bank account, here’s what every founding team should talk through together, in the open, to avoid money issues between cofounders.

If you were getting married to the love of your life, even though you trust that person, you’d probably still talk about finances before making it a done deal, not because you’re planning for disaster, but because pretending money won’t matter is… optimistic. You’d likely discuss things like: How do we split expenses? What’s our budget? What happens if one person earns more — or nothing at all — for a while? 

A cofounder prenup involves having that same conversation, but with your business partner. It’s not an actual legal document, but rather a set of honest conversations to help you get aligned and document your approach to handling money. 

Starting a company together is a legal partnership with real financial consequences. There’s cofounder equity split, risk, debt, outside investors, and long stretches where the business might not pay you at all. And, yet, many founders jump in without ever saying out loud what they’re assuming will happen.

Take these cautionary tales from Reddit threads: 

• One co-founder says she lost trust over a cofounder equity split dispute. 
• One says their co-founder is too risk-averse when it comes to spending.
• Another says their co-founder is spending too much.
• One is unsure how to navigate a partnership with co-founders with different salary needs. 

These examples are exactly why the cofounder prenup is so important. It’s a shared understanding of who’s putting in what, how upside and downside are handled, and what happens if life intervenes or priorities change. It covers things like capital contributions, variable salaries, equity splits, personal runway, and exit expectations — before stress, scarcity, or a term sheet show up.

Navigating a business partnership requires nuance and care. “Cofounder relationships can be hard,” Charity Majors, honeycomb.io co-founder and CTO, wrote in an article on communication. “They are a lot like marriages; in their difficulty and intensity, yes, but also in that when you’re doing it with the right person, it’s all worth it.”

Here are the foundational questions at the heart of the cofounder prenup. No legal language here — just real cofounder financial questions that will help you and your partner get clear on expectations — and avoid relying on assumptions. 

Here are conversations worth having early:

• Are we both investing personal funds? How much, and when? Is this a bootstrapped start with equal cash in, or is one person funding the early days? If contributions aren’t equal, how is that recognized?
• Can either of us afford to go without a salary? For how long? A “we won’t pay ourselves at first” attitude sounds simple — until rent is due. Be honest about timelines, pressure points, and non-negotiables.
• What does each of our personal runways look like? How many months can each founder realistically operate without income? If one cofounder’s personal runway is much shorter, that affects risk tolerance and decision-making.
• How are we splitting equity, and why? Is the split based on role, idea, time commitment, capital, or something else? Will it vest? Will it be revisited as the company evolves?
• What happens if one of us has to leave? Life happens: Health issues, burnout, and better opportunities come up. Talk now about equity cliffs, buybacks, and what “fair” looks like if someone exits early.
• Will any IP, assets, or side work stay personal? Are there pre-existing tools, code, or relationships coming into the business? What’s owned by the company versus each individual?
• How will we handle expenses and reimbursements? Who pays for what upfront? How are shared costs tracked? When does the company start covering expenses, instead of founders floating them?
• Are we opening a joint business bank account? Keeping personal and business money separate isn’t just cleaner, it also prevents misunderstandings and makes future fundraising far easier.
• How will major financial decisions get made? Who has signing authority? Do large expenses, debt, or fundraising decisions require unanimous approval, or does one founder have final say?
• What’s our risk tolerance when it comes to money? Are we conservative about spending or comfortable with moving fast and burning cash to grow? Misaligned risk tolerance is one of the quiet drivers of founder conflict.

None of these questions are inherently uncomfortable. These topics only become uncomfortable when ignored too long. Getting them on the table early helps to create alignment and gives both founders confidence that they’re building on shared ground, not silent assumptions.

Let’s be honest: No one wakes up excited to say, “Hey, can we talk about money and worst-case scenarios?” The way you frame this conversation matters just as much as the questions themselves.

Here are a few principles that make it easier for everyone involved:

• Start from a place of mutual protection, not suspicion. Lead with intent to protect both your relationship and the company. A simple opener like, “I want us to stay aligned, even when things get stressful” sets the right tone.
• Use a neutral framework. Having a shared doc or checklist keeps the conversation from feeling too personal or accusatory. That way you’re responding to questions on a page, not interrogating each other. (Bonus: This approach also makes follow-ups easier later.)
• Normalize transparency early. Money gets harder to talk about once investors, salaries, or other pressures enter the picture. Talking openly now sets a precedent that financial transparency is part of how you operate, not something you avoid.
• Assume you’ll revisit this. This isn’t a one-and-done conversation. Founders evolve. Companies change. Treat this as version one and plan for regular check-ins, as roles, revenue, and risk shift.
• Loop in legal (later). Lawyers are essential when building a business, but starting with legal language can shut down honest discussion. Get aligned as humans first. Then, formalize it once you’re on the same page.

Come to these talks with a spirit of collaboration. “Frame the conversation as partners tackling a shared challenge, not opponents in conflict,” wrote Christine Carrillo, a CEO coach and entrepreneur, in an essay. She suggests avoiding “you versus me” language, which can feel combative, elicit defensive responses, and derail discussions.  “The best tough conversations unite two people solving a problem together. The simplest way to make this shift is by replacing ‘you’ with ‘us.”

For more tips for having these hard conversations, there are plenty of great books out there, including Crucial Conversations and Non-Violent Communication: A Language of Life.

Once you’ve aligned on the money, the last thing you’ll want is clunky systems that create new problems. The goal is to make the financial side of your partnership feel simple, visible, and low-drama. That’s where Mercury comes in.

With Mercury, cofounders can:

• Open a shared business account quickly. Get your shared business bank account set up fast, without weeks of back-and-forth. That way you can start operating as a united company, not a fragmented collection of personal accounts.
• Track capital contributions clearly. Whether one founder is fronting cash or both are investing equally, make sure everything is documented and easy to reference.
• Keep personal and business expenses separate. Clean boundaries from day one mean fewer misunderstandings and far less cleanup later (especially when tax time rolls around).
• Prepare for future investors with clean financial ops. Organized accounts and clear transaction history make diligence smoother when fundraising enters the picture.

When the mechanics are frictionless, money stops being a constant discussion point. Instead, it becomes a type of infrastructure — supporting the work, not complicating your relationship.

Now that you’ve done the hard part by having these conversations with your cofounder, Mercury helps make the follow-through easy with clean accounts, shared visibility, and fewer money-related headaches. 

Get started and apply for a Mercury account today.