What should a co-founder agreement include?

Learn what to include in a co-founder agreement to protect your startup. Explore equity vesting, IP ownership, roles, and dispute resolution for founders.

8 min readUpdated September 2026

The short answer

A co-founder agreement is a foundational document that outlines the roles, equity distribution, and responsibilities of a startup's founding team. Unlike a formal company constitution, this private contract addresses potential conflicts before they arise. It must cover ownership percentages, vesting schedules, decision-making powers, and what happens if a founder leaves. Having this in place early prevents costly litigation and provides clarity to future investors about the stability of the management team.

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Equity Split and Vesting Schedules

The most critical part of the agreement is how ownership is divided. Founders often default to equal splits, but this does not always reflect the value brought by each person. You should consider factors like technical expertise, capital contribution, and initial time commitment when deciding percentages.

Vesting is essential to ensure founders stay committed for the long haul. A standard four-year vesting period with a one-year cliff is common in the US and UK. This means if a founder leaves before the one-year mark, they walk away with nothing, protecting the remaining founders from 'dead equity' on the cap table.

  • Initial equity percentage for each founder
  • Vesting period duration (typically 3-4 years)
  • One-year cliff provision
  • Acceleration clauses upon acquisition
  • Treatment of unvested shares if a founder is terminated
  • Buy-back rights for the company

Roles and Decision-Making Authority

Ambiguity in leadership can paralyze a startup during high-pressure situations. The agreement should define specific titles such as CEO, CTO, or COO, while outlining the primary responsibilities of each role. This avoids overlapping duties and helps the team move faster.

Beyond daily tasks, you must define how major decisions are made. This includes hiring senior staff, raising debt, or pivoting the business model. In India and the EU, certain corporate actions may require specific board approvals, so aligning the founder agreement with local company law is vital.

  • Primary job titles and descriptions
  • Voting rights for major business decisions
  • Tie-breaking mechanisms for deadlocked votes
  • Daily operational autonomy limits
  • Procedures for removing a founder from their role

Intellectual Property Ownership

Investors will rarely fund a company that does not clearly own its core technology or branding. The agreement must state that all work created by founders for the startup belongs to the company, not the individual creator. This is often handled through an IP assignment clause.

Without this clause, a departing founder could legally claim ownership of the codebase or trademarks, effectively holding the company hostage. Ensure that the assignment covers past, present, and future work related to the business venture.

  • Formal assignment of all IP to the entity
  • Disclosure of any prior inventions
  • Warranties that the IP does not infringe third-party rights
  • Prohibition on using company IP for personal projects
  • Survival of IP obligations after departure

Exit Strategies and Departure

Founders often leave due to burnout, personal reasons, or disagreements. The agreement should define 'Good Leaver' and 'Bad Leaver' scenarios. A Good Leaver might keep their vested shares, while a Bad Leaver - such as someone fired for fraud - may be forced to sell everything back at a nominal price.

In the US, 'at-will' employment concepts influence these exits, whereas in the UK and India, employment contracts might require longer notice periods. Clearly defining the process for resignation or removal prevents legal surprises later.

  • Definition of Good Leaver vs. Bad Leaver
  • Notice periods for voluntary resignation
  • Valuation methods for share buy-backs
  • Rights of first refusal (ROFR) for remaining founders
  • Drag-along and tag-along rights for future sales

Confidentiality and Non-Competes

Founders have access to the company's most sensitive data. A robust confidentiality clause ensures that trade secrets stay protected even if a founder leaves. This should be comprehensive and last indefinitely for truly sensitive information.

Non-compete clauses are common but subject to varying regional laws. For instance, non-competes are largely unenforceable in California, while they are permitted in many other US states and the UK if they are reasonable in scope and duration. In India, post-employment non-competes are generally difficult to enforce.

  • Duration of non-compete restrictions
  • Geographic scope of non-compete clauses
  • Non-solicitation of employees and customers
  • Definition of confidential information
  • Exclusions for publicly available information

Sample clause language

Illustrative wording, written for this guide — not copied from any real contract.

Risky Equity Clause
All equity shall be split equally among the founders immediately upon signing. No vesting shall apply, and each founder has full rights to their shares regardless of their future involvement in the company.

This is highly risky because a founder could quit on day two and still own a massive portion of the company, making it uninvestable.

Balanced Vesting Clause
Founder shares shall vest over forty-eight months, with a twelve-month cliff. If a Founder ceases to be an employee for any reason other than a Bad Leaver event, they shall retain all vested shares, while the company maintains a right to repurchase unvested shares at cost.

This protects the company's cap table while rewarding the founder for the time they actually contributed to the business.

Red flags to look for

  • No vesting schedule for founder equity
  • Absence of an IP assignment clause
  • No clear process for resolving deadlocked decisions
  • Equal splits without considering actual contributions
  • Vague definitions of 'Bad Leaver' scenarios
  • Lack of a clear buy-sell agreement for departing founders

Not sure whether your contract has these problems? Lawly AI reads the whole document, quotes the risky wording back to you, and scores the overall risk in about a minute.

What to ask for

  • The length and conditions of the cliff period
  • Acceleration of vesting upon the sale of the company
  • Specific veto rights for minority founders on certain topics
  • The valuation method used for share buy-backs
  • Scope and duration of non-compete restrictions

Check this in your own contract

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Frequently asked questions

When should we sign a co-founder agreement?

As soon as you decide to work together seriously. Waiting until you have revenue or funding often makes negotiations harder because the stakes are higher.

Is a co-founder agreement legally binding?

Yes, it is a private contract. While it is not a public filing like Articles of Incorporation, it is enforceable in court or arbitration.

What happens if we don't have an agreement?

Default state laws apply, which often mean equal ownership and no vesting. This can lead to messy lawsuits if one founder leaves or if roles become unclear.

Can we change the agreement later?

Yes, but only if all parties agree in writing. It is common to update the agreement as the company grows or as new founders join.

Related guides

This guide is general educational information about how these clauses usually work. It is not legal advice, and contract law differs by jurisdiction. For a decision that matters, speak to a qualified lawyer.