Founders' Agreement Template: Equity, Vesting, the 83(b) Election, and a Free Structure (2026)

Written by

Helena Kozlova in

Legal Content Specialist, AI Lawyer

~12 min read · Updated May 2026

Fact-checked by

Kamal Tserakhau in

Legal Team Lead · AI Lawyer

Reviewed for accuracy · Verified May 2026

A founders' agreement is the deal between co-founders about the things that wreck startups: who owns how much, what happens if someone leaves, who decides what, and who owns the code and the idea. Most templates cover the obvious parts and miss the two that cost founders the most: a vesting schedule that protects the company, and a 30-day tax election that can save each founder a fortune. This guide shows you what to include, how to split equity, how vesting and the cliff work, why IP assignment is non-negotiable, and the 83(b) election you cannot afford to miss.

The short answer

A founders' agreement sets each co-founder's equity, vesting, roles, decision rights, IP assignment, and what happens on departure. The market standard for vesting is four years with a one-year cliff, so a founder who leaves in the first year keeps nothing. Every founder must assign their past and future IP to the company, or fundraising will stall. And if you receive restricted stock subject to vesting, you generally have just 30 days from the grant to file an 83(b) election with the IRS, which can save you a large tax bill later. Put it all in writing before the company is worth fighting over.

This article is general information for a U.S. audience, not legal or tax advice. Equity, vesting, and tax elections have real financial consequences, so have a startup attorney and a tax professional review your setup, especially the 83(b) election.

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4 yr / 1 yrthe standard vesting schedule and cliff

IPassign all founder IP to the company, or fundraising stalls

30 daysthe strict 83(b) election window after a restricted-stock grant

In writingsettle the hard questions before the company is worth fighting over

What is a founders' agreement?

A founders' agreement is a contract among a startup's co-founders that sets out equity ownership, vesting, roles and responsibilities, decision-making, intellectual-property assignment, compensation, and what happens if a founder leaves. It is the document that turns an informal partnership into a clear deal, so the team has answers before the hard questions arrive.

Most co-founder disputes are not about strategy; they are about ownership and exit. The founders' agreement exists to settle those while everyone is still aligned and the equity is worth little, which is exactly when these conversations are easiest to have.

Once you incorporate, parts of this agreement get formalized into stock-purchase agreements, bylaws, and a shareholder agreement. But the founders' agreement is where the team first writes down the deal.

What should a founders' agreement include?

A solid founders' agreement covers the equity split, the vesting schedule and cliff, each founder's role and decision rights, an assignment of all founder IP to the company, compensation or sweat-equity terms, confidentiality, and the departure and buyback mechanics. Equity, vesting, and IP assignment are the three that carry the most weight.

The anatomy of a founders agreement: equity split, vesting, IP assignment, roles, decisions, exit — The anatomy of a founders' agreement, from the equity split through to exit.

Clause	What it should say
Equity split	Each founder's ownership percentage at founding, and the rationale
Vesting and cliff	How and when each founder earns their shares
Roles	Each founder's title, domain, and day-to-day authority
Decision-making	How major decisions are made and how ties are broken
IP assignment	Each founder assigns all past and future company IP to the company
Compensation	Salary, sweat equity, or deferred pay, and expense rules
Departure and buyback	What happens to a leaving founder's vested and unvested shares
Confidentiality	Protection of the company's confidential information

The clause founders skip is the tie-breaker, and the one they get wrong is IP assignment. Both are covered below.

How should founders split equity?

There is no formula, but the split should reflect each founder's contribution: time commitment, prior work or IP, capital, and role. Equal splits work for founders who are equally committed; weighted splits make sense when contributions differ. Whatever you choose, document the percentages and the reasons, and avoid a pure 50/50 with no way to break a deadlock.

Three equity-split models: equal for matched commitment, weighted for differing contribution, smaller grants for part-time or advisory roles — Three common equity models, matched to how much each founder brings.

The hardest split is the one that feels fairest in the moment: a clean 50/50 between two founders. It is fine, as long as the agreement names a tie-breaker for deadlocks, because two equal owners who disagree can otherwise freeze the company. Decide the split on contribution, then write down how you will resolve a standoff.

How does founder vesting work, and what is a cliff?

Vesting means a founder earns their shares over time instead of owning them all on day one. The market standard is four years with a one-year cliff: nothing vests until the founder has been with the company for 12 months, when 25% vests at once, and the rest vests monthly over the next three years. A founder who leaves before the cliff keeps nothing, which is exactly the point.

Time with the company	Shares vested
Before 12 months (the cliff)	0%
At 12 months	25% (the cliff vests at once)
Months 13 to 48	The remaining 75%, vesting monthly
At 48 months	100% fully vested

Vesting protects the founders who stay and the company itself. Without it, a co-founder can leave after a few months and keep a large, fully owned slice of the company, which makes the cap table toxic and scares off investors. Investors expect founder vesting, so adding it early is a signal of a serious team.

Why must founders assign their IP to the company?

Because without it, the company may not actually own the product. Each founder should assign all relevant past, present, and future intellectual property, including code, designs, and inventions, to the company as a condition of their equity. If a founder later leaves still owning the core IP, fundraising stalls, because investors will not fund a company that does not clearly own what it sells.

This is the founders' agreement equivalent of the work-made-for-hire problem in development contracts: paying for or building something is not the same as the company owning it. An express assignment from each founder to the company is what makes ownership clean.

Diligence will test this. When you raise money or sell the company, the buyer's lawyers check that every founder assigned their IP. A gap here can delay or kill a deal, so close it at formation.

The 83(b) election: a 30-day decision you cannot miss

If you receive restricted stock subject to vesting, you generally have only 30 days from the grant to file an 83(b) election with the IRS. It lets you be taxed on the stock's value at grant, which for a new company is often near zero, instead of being taxed as each tranche vests, when the company may be worth far more. The 30-day deadline is strict, with no extensions, and missing it can cost a founder a large tax bill later.

This is the single most expensive thing founders overlook. Under Internal Revenue Code §83, restricted stock is normally taxed as it vests, at the value on each vesting date. For a successful startup, that means a growing tax bill on illiquid stock you cannot sell to pay it.

The fix is to file an 83(b) election within 30 days of the grant, electing to be taxed now on the full value (usually tiny at founding). The future appreciation is then taxed as capital gain when you sell, not as ordinary income as it vests. The deadline cannot be extended for any reason, so calendar it the day you receive restricted stock and confirm the filing with a tax professional.

What happens when a co-founder leaves?

The departure and buyback terms decide it. A leaving founder keeps only their vested shares, and the company usually has the right to repurchase unvested shares, sometimes at the price the founder paid. The agreement should also address whether the company can buy back vested shares, and how a departing founder's role and confidentiality obligations continue. Clear leaver terms prevent a former co-founder from holding the company hostage.

This is where vesting does its work. Because a departing founder forfeits unvested shares, an early exit does not leave a large dead-weight stake on the cap table. Spell out the repurchase right, the price, and the timeline so the mechanics are automatic rather than a negotiation during a stressful exit.

Common mistakes to avoid

The mistakes that sink startups are predictable: no written agreement, no vesting, no IP assignment, a deadlocked 50/50 with no tie-breaker, and missing the 83(b) election window. Each one is cheap to fix at formation and expensive to fix later.

Operating on a handshake with no founders' agreement at all.
Skipping vesting, so a founder who leaves early keeps a large stake.
Failing to have each founder assign their IP to the company.
A pure 50/50 split with no mechanism to break a deadlock.
Missing the 30-day 83(b) election window on restricted stock.

Frequently asked questions

Do co-founders really need a written founders' agreement?

Yes. The hardest startup disputes are about ownership and exit, and a written founders' agreement settles them in advance, while the equity is still worth little and the team is aligned. It also signals to investors that the founders are serious, and it prevents a departing co-founder from keeping an outsized stake.

How should we split founder equity?

Base it on contribution: time commitment, prior work or IP, capital, and role. Equal splits suit equally committed founders; weighted splits suit unequal contributions. Document the percentages and the reasoning, and if you choose 50/50, include a tie-breaker so a deadlock cannot freeze the company.

What is the standard vesting schedule for founders?

Four years with a one-year cliff. Nothing vests for the first 12 months; at the one-year mark 25% vests at once, and the remaining shares vest monthly over the next three years. A founder who leaves before the cliff forfeits all of it, which protects the founders who stay.

What is a vesting cliff?

It is a minimum period, usually 12 months, that a founder must complete before any equity vests. If they leave before the cliff, they forfeit the entire unvested grant. The cliff stops a short-tenure founder from walking away with a meaningful ownership stake.

What is an 83(b) election and when do I file it?

It is an IRS election that taxes restricted stock at its value when granted, rather than as it vests. You generally must file it within 30 days of the grant, and the deadline cannot be extended. For founders whose stock is worth almost nothing at founding, filing can convert future gains from ordinary income into capital gain and save a large tax bill.

Why do founders have to assign their IP to the company?

So the company clearly owns what it sells. Without an assignment, a founder can leave still owning the core code or invention, which stalls fundraising because investors will not fund a company that does not own its product. Each founder should assign all relevant past and future IP to the company at formation.

What happens to a co-founder's equity if they leave?

They keep their vested shares, and the company usually has the right to repurchase the unvested ones, often at the price the founder paid. Good departure terms also address vested-share buybacks, ongoing confidentiality, and the timeline, so an exit follows clear rules instead of a fight.

Is a founders' agreement the same as an operating agreement or bylaws?

No. A founders' agreement is the early deal among the founders. Once you incorporate, its terms are formalized into stock-purchase agreements with vesting, corporate bylaws, and a shareholder agreement. The founders' agreement is where the deal starts, not the final corporate paperwork.

Sources and references

Internal Revenue Code §83 and the 83(b) election, on the taxation of restricted property and the 30-day filing window.
Standard startup practice on four-year vesting with a one-year cliff and founder IP assignment (Carta, Cooley GO, and startup-law practitioners).
General U.S. principles on equity splits, decision rights, and founder departure terms.

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