Founders Agreement: 8-Clause Guide for Startups (2026)

What Is a Founders Agreement and Why Does Every Startup Need One?

A founders agreement is a legally binding contract between co-founders that defines equity ownership, roles and responsibilities, intellectual property rights, vesting schedules, and departure procedures. Most guides treat it as a single document. It isn't — it's a coordinated package of two to four aligned documents, and misaligning even one of them is how co-founding teams end up in costly litigation before they reach Series A.

Key takeaways

• A founders agreement is not one PDF — it's a package of aligned documents: the agreement itself, a Restricted Stock Purchase Agreement, an IP assignment, and an 83(b) election filed within 30 days.
• The four-year vesting schedule with a one-year cliff is the investor-standard structure; deviating from it requires a clear documented rationale.
• "Good leaver" and "bad leaver" have no legal definition under U.S. law — your agreement must define them explicitly, or those terms are meaningless.
• California SB 699 (effective January 1, 2024) voids non-competes even if signed in another state; a non-compete clause aimed at California-based founders is now a civil violation, not just unenforceable.
• The 83(b) election window is 30 calendar days from the stock transfer date — not 30 days from signing paperwork. The IRS does not grant extensions.

Why Most Founders Get the Agreement Structure Wrong

The single most common structural error is treating the founders agreement as one standalone contract. In practice, a founders agreement is a coordinated four-document package:

Document	What It Does	When You Need It
Founders Agreement	Defines roles, equity percentages, decision-making authority, IP ownership, departure terms, and non-solicitation	At or before incorporation
Restricted Stock Purchase Agreement (RSPA)	Makes founder equity real on the cap table; contains the actual vesting schedule and company repurchase rights	Same day as founders agreement
IP Assignment Agreement	Transfers all pre-incorporation and post-incorporation IP from founders individually to the company	Same day as founders agreement
IRS Form 15620 (83(b) Election)	Locks in tax basis at grant-date value so future appreciation is taxed as capital gain, not ordinary income	Within 30 calendar days of stock transfer

Skipping the RSPA means vesting terms are aspirational, not enforceable as company repurchase rights. Skipping IP assignment means a departing founder may retain ownership of the codebase. Skipping the 83(b) election triggers an ordinary income tax event at every future vesting milestone — often when the stock is illiquid and the founder cannot sell to cover the bill.

Before you write a clause of the founders agreement, confirm all four documents are on your closing checklist. Create your Founders Agreement on Pactlio — describe your deal in plain English and our AI agents draft a review-ready document covering all key terms.

The 8 Clauses Every Founders Agreement Must Cover

1. Equity Split

Document the exact ownership percentage for each founder. Base it on factors that will hold up in an investor's due diligence conversation: expected future time commitment, capital contributed, prior IP being assigned, relevant domain expertise, and customer or investor relationships brought to the company.

Common structures:

Model	Works Best When
Equal split (e.g., 50/50, 33/33/33)	All founders commit full-time from day one with comparable contributions
Weighted split	One founder contributes significant prior IP, capital, or specialized expertise
Dynamic (e.g., Slicing Pie)	Contributions will vary substantially and are hard to predict upfront
Equal split + option pool reserve	Founders split equally, with 10–15% reserved for future hires and advisors

Document the rationale in writing alongside the percentage — not just the number. Investors will ask why the split was structured a specific way, and a written explanation builds confidence. Undocumented splits are a due diligence red flag.

2. Vesting Schedule

Vesting protects the company and remaining founders if someone leaves early. The investor-standard structure is a four-year vesting schedule with a one-year cliff: nothing vests in the first 12 months; at month 12, 25% vests immediately; the remaining 75% vests in monthly installments over the following 36 months.

Without vesting, a co-founder who leaves after six months keeps their full equity stake forever — creating what investors call "dead equity" on the cap table. That situation does not just feel unfair; it makes the company structurally unfundable.

You can add an acceleration clause, but most institutional investors prefer either no acceleration or double-trigger acceleration only: vesting speeds up only if both an acquisition occurs and the founder is involuntarily terminated afterward.

3. Intellectual Property Assignment

Under U.S. copyright law, IP vests in the individual creator by default. A founders agreement must include an express IP assignment clause covering all work created for the startup — code, designs, inventions, trademarks — whether created before or after incorporation.

Pre-incorporation IP is where most teams get into trouble. Code written on nights and weekends before the company existed belongs to the individual founder who wrote it unless explicitly assigned. List pre-existing IP in a schedule attached to the agreement and assign it to the company. Investors and acquirers will conduct IP chain-of-title searches; any gap in assignment is a negotiating weapon against you.

One California-specific carve-out: California Labor Code § 2870 exempts inventions developed entirely on your own time, without company resources, and unrelated to the company's business. Acknowledge this exception in your IP clause rather than trying to override it — courts will not enforce an assignment that ignores § 2870.

For more on structuring IP protections across your full contract stack, see our guide to IP clauses in contracts.

4. Roles, Responsibilities, and Decision-Making

Specify titles (CEO, CTO, COO), the areas each founder owns day-to-day, and the decision thresholds that govern major actions:

• Unilateral decisions: each founder can make these in their own domain without asking others
• Majority vote decisions: hiring above a salary threshold, entering major contracts, spending above a dollar cap
• Reserved matters (unanimous consent): issuing new equity, taking on debt above a defined amount, selling material assets, bringing on a new co-founder

Deadlock provisions are mandatory for 50/50 splits. Without one, any unresolved deadlock on a major decision defaults — under corporate law — to dissolution as the only remedy. Common deadlock mechanisms include binding mediation, a rotating tiebreaker, or a designated neutral advisor with a tie-breaking vote. Penn Law's founders agreement overview recommends binding confidential mediation as a practical default for factual disputes.

5. Good Leaver and Bad Leaver Terms

Good leaver and bad leaver have no statutory definition under U.S. law. Their meaning is entirely what your founders agreement says they mean. An agreement that uses these terms without defining them is a litigation waiting to happen.

Define both explicitly:

• Good leaver: departure due to death, permanent disability, mutual agreement, or termination without cause. Good leaver founders typically retain their vested shares and sometimes receive partial credit toward unvested shares.
• Bad leaver: voluntary resignation, termination for cause (define cause: fraud, gross misconduct, material breach of fiduciary duty). Bad leaver founders typically lose unvested shares to company repurchase at par value ($0.0001/share), and some agreements allow repurchase of vested shares at fair market value.

Define "cause" precisely — vague language like "acts inconsistent with the company's best interests" invites disputes.

6. Founder Departure and Exit Mechanics

Cover every departure scenario:

• Voluntary resignation: unvested shares return to the company; vested shares retained (unless bad leaver terms apply)
• Termination for cause: specify the process — notice, cure period, board vote threshold
• Death or permanent disability: company has the right (but not the obligation) to repurchase shares from the estate at fair market value
• Buyout price: how is fair market value determined? An independent 409A valuation is the standard mechanism

Include a right of first refusal (ROFR): before a founder can transfer shares to a third party, the company and existing founders have the right to purchase those shares at the offered price. This keeps the cap table clean and prevents a former founder from selling equity to a competitor.

7. Confidentiality

Confidentiality obligations covering business plans, technology, customer lists, and financial information should survive a founder's departure. This is your first line of trade secret protection under the federal Defend Trade Secrets Act (DTSA), 18 U.S.C. § 1836, which gives companies a federal civil cause of action for trade secret misappropriation — including injunctive relief and damages.

8. Non-Compete and Non-Solicitation

Whether a non-compete is worth including depends entirely on where your founders live:

California founders: California Business & Professions Code § 16600, reinforced by SB 699 (codified as B&P § 16600.5, effective January 1, 2024), makes non-competes void in the employment and co-founder context. SB 699 extended this ban to agreements signed in other states — a Nevada employer cannot enforce a non-compete against a California-based founder even if the contract specifies Nevada law. Attempting to enforce such a clause is now a civil violation carrying a private right of action for damages and attorney's fees.

Founders in most other U.S. states: Reasonable non-competes are generally enforceable if limited in duration (6 months to 2 years is typical), geographic scope (limited to where the company operates), and restricted activities (narrowly defined). Minnesota and North Dakota also ban them outright.

A non-solicitation clause — preventing a departing founder from recruiting employees or approaching current customers — is more broadly enforceable in California and is worth including everywhere. For a full state-by-state breakdown, see our guide to non-compete law by state.

The 83(b) Election: What the Tax Math Actually Looks Like

This is the clause most guides summarize in two sentences. Here is what it actually costs to miss it.

Scenario: Three co-founders each receive 1,000,000 shares of restricted stock at a purchase price of $0.001/share (total cost: $1,000 per founder) on day one. The company raises a Series A 18 months later, and an independent 409A valuation sets common stock at $2.00/share.

Without an 83(b) election: Under IRC § 83(a), each vesting event is a taxable income event. At month 12 (cliff), 250,000 shares vest at $2.00/share = $500,000 of ordinary income, taxed at up to 37% federal = $185,000 in federal taxes due — on stock the founder cannot sell. Months 13-18 add another ~12.5% (125,000 shares × $2.00 = $250,000 of additional ordinary income = ~$92,500 more in federal taxes). Total federal tax exposure from vesting events alone in the first 18 months: ~$277,500 per founder, owed on illiquid shares.

With an 83(b) election filed within 30 days of grant: The founder pays tax on the grant-date spread — $1,000 paid for $1,000 of value = $0 of ordinary income. All future appreciation is capital gain, taxed at the long-term capital gains rate (currently a maximum of 20% for high earners under IRC § 1(h)) once shares are held more than one year. The same $750,000 of value appreciation would produce ~$150,000 in tax instead of $277,500 — and only when the founder actually sells.

The 2025 update on filing: On November 7, 2024, the IRS released Form 15620 as the standardized form for 83(b) elections. In 2025, the IRS enabled online filing through its "mobile-friendly forms" portal at irs.gov — electronic submission is now the IRS's preferred method and provides instant confirmation of receipt. The 30-day deadline from the stock transfer date remains unchanged and absolute; the IRS does not accept late filings regardless of method. After filing, provide a copy to the company so it can report income inclusion correctly. If your grant involves more than 99,999,999 shares or a price per share below four decimal places, consult counsel on whether paper filing is more appropriate for your facts.

Set a calendar reminder for day one — before you sign anything else.

The Real Cost of Skipping It: The Snapchat Lesson

Reggie Brown conceived the original idea for disappearing photo messages that became Snapchat. He collaborated with Evan Spiegel and Bobby Murphy through the app's early development, co-filed patent applications, and even named the company. There was no founders agreement governing his equity, role, or departure terms. Spiegel and Murphy pushed him out of the company without compensation.

Brown sued in 2013. Snap settled in September 2014 for $157.5 million, a figure confirmed in Snap Inc.'s 2017 SEC S-1 filing. The settlement did not make Brown a billionaire alongside his co-founders — it compensated him at a fraction of what a documented equity stake would have been worth at Snap's $25 billion IPO valuation. The absence of a signed agreement did not protect the founders who stayed; it cost the company $157.5 million and created reputational complexity in their IPO documentation.

A one-afternoon negotiation and a signed document would have resolved Brown's role and equity at a cost of zero.

For more on the documents every early-stage company needs alongside a founders agreement, see contracts every startup needs.

Founders Agreement vs. Shareholders Agreement: When You Need Each

	Founders Agreement	Shareholders Agreement
Timing	At or before incorporation (pre-seed)	After a priced equity round (Series A or later)
Covers	Founding team only	All shareholders: founders + investors
Key terms	Equity percentages, vesting, IP assignment, roles, founder exits, non-solicitation	Board composition, anti-dilution, liquidation preferences, drag-along/tag-along, information rights
Replaces the other?	No — evolves into the shareholders agreement at fundraising	No — builds on the founders agreement
Who negotiates	Founders among themselves	Investors and founders, typically with attorneys

One practical note: include an amendment mechanism that does not require unanimous consent from every party. If a founder has departed and gone dark, an amendment clause requiring their signature can stall your fundraising close entirely. A majority or supermajority threshold (e.g., 75% of outstanding shares) is a safer default than unanimity.

For a deeper look at how the shareholders agreement fits into your governance stack, see our shareholders agreement guide.

Jurisdiction Notes

Jurisdiction	Key Considerations
Delaware C-corp	The standard for VC-backed startups. Delaware's Court of Chancery provides deep corporate law precedent. Reasonable non-competes with departing founders are generally enforceable.
California	Non-competes in the founder/employment context are void under B&P Code § 16600 and § 16600.5. Focus on IP assignment, DTSA-backed confidentiality, and narrow non-solicitation clauses.
New York	Moderate non-compete enforcement; courts apply a reasonableness test. No blanket ban.
Minnesota / North Dakota	Near-categorical bans on non-competes, similar to California.
Multi-state founding teams	The governing law clause determines which state's law applies to disputes. Delaware is the standard choice for its predictable, well-developed corporate law.

For founding teams spread across states or countries, choose governing law deliberately. A founder who lives in California but whose agreement specifies Delaware law may still argue California public policy applies to California-based activities.

How to Execute a Founders Agreement: Step by Step

1. Align on equity philosophy before opening a template. Discuss each founder's expected future time commitment, capital contribution, and prior IP. Write down the rationale.
2. Inventory all pre-existing IP. List every piece of code, design, patent application, or trade secret created for the company before incorporation. Every item on that list must be assigned.
3. Choose your vesting structure. Standard: 4-year, 1-year cliff, monthly vesting thereafter. Document any acceleration terms (and be prepared to justify single-trigger acceleration to investors).
4. Define good leaver, bad leaver, and cause explicitly. Do not use those terms without definitions.
5. Draft the founders agreement and RSPA together, not separately. Vesting terms in both documents must match exactly.
6. Have a startup attorney review before signing. A template review for a pre-revenue startup typically costs $300–$600 — a fraction of the cost of any future dispute.
7. Sign, issue shares, update the cap table, and file 83(b) elections within 30 days. Use IRS Form 15620 via the IRS online portal at irs.gov. File electronically for instant confirmation of receipt. Provide a copy to the company.
8. Set a review trigger. Revisit the agreement when a new co-founder joins, when roles change significantly, or at each financing round.

Generate a founders agreement with Pactlio — describe your deal structure in plain English and our AI agent panel drafts a review-ready document.

For guidance on negotiating the terms before you sign, see our guide to how to negotiate contracts.

Common Mistakes to Avoid

• Equal split with no vesting. An equal split is not inherently wrong. An equal split without vesting is structurally dangerous — it means any founder can leave after three months and keep their full stake permanently. Always use vesting, regardless of how equity is divided.
• Leaving pre-incorporation IP unassigned. Code or designs built before the company formed belong to the individual who created them unless explicitly assigned. Attach a schedule and assign it in the agreement.
• Using "good leaver / bad leaver" without defining them. These phrases have no statutory meaning in U.S. law. Undefined, they are litigation triggers, not resolution mechanisms.
• Missing the 83(b) deadline. The IRS does not grant extensions. Set a calendar reminder for day one — the clock runs from the date of stock transfer, not from the date you receive paperwork.
• Requiring unanimous consent to amend. If a founder departs and becomes uncooperative, a unanimity clause can make the agreement impossible to update and block your next funding round.
• Skipping the RSPA. Without a Restricted Stock Purchase Agreement, vesting terms in the founders agreement are not backed by enforceable company repurchase rights.

Sources

• IRS Form 15620 — Section 83(b) Election (standardized form, released November 2024): https://www.irs.gov/forms-pubs/update-to-the-2024-publication-525-for-section-83b-election
• Mintz — New Electronic Filing Option for Section 83(b) Elections: https://www.mintz.com/insights-center/viewpoints/2906/2025-07-29-new-electronic-filing-option-section-83b-elections
• Sidley Austin — 83(b) Goes Digital: Two Quirks Founders Should Know: https://www.sidley.com/en/insights/newsupdates/2025/08/83b-goes-digital-two-quirks-founders-should-know-before-you-click-submit
• California Business & Professions Code § 16600 and § 16600.5 (SB 699, effective January 1, 2024): https://legiscan.com/CA/text/SB699/id/2839277
• Paul Weiss — California Non-Compete Laws Take Effect (SB 699 and AB 1076 analysis): https://www.paulweiss.com/insights/client-memos/california-non-compete-laws-take-effect
• California Labor Code § 2870 (IP assignment exception): https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?sectionNum=2870.&lawCode=LAB
• Defend Trade Secrets Act, 18 U.S.C. § 1836: https://uscode.house.gov/view.xhtml?req=granuleid:USC-prelim-title18-section1836
• Snap Inc. S-1 (Reggie Brown settlement disclosure, $157.5M): https://techcrunch.com/2017/02/02/snapchat-reggie-brown/
• EquityList — Founders' Agreement for U.S. Companies: https://www.equitylist.co/blog-post/founders-agreement-for-us-companies
• University of Pennsylvania Law School — Founders' Agreement Overview: https://www.law.upenn.edu/clinic/entrepreneurship/startupkit/founders-agreement.pdf

This article is general information, not legal advice. Laws vary by jurisdiction. Pactlio generates professional drafts for review — have a licensed attorney review anything important.