Two-Founder Equity Split and Vesting Checklist

You are about to sign formation documents, and the equity split is still a handshake. Make it a checklist now, because about three in ten startups lose a cofounder by the fourth year. The split and vesting terms are the cheapest way to keep the company stable if the partnership changes.

The split is where the argument starts

A small gap can prevent a tie. It gives the person with more responsibility a little more stake. Equal splits need a reason. If you choose equal, write a short memo that names the reasons: shared risk, shared hours, shared prior work, and a plan for who makes the final call. If you choose a gap, make the gap match the difference in contribution, not the difference in confidence.

Put the contribution on a page. Who has already spent time building the product? Who has the customer relationships? Who is taking on the day-to-day operations? Who is bringing the technical skill that makes the product possible? The answer should be visible in the split, or in the memo if the split is equal.

Vesting is the tripwire that protects the founder who stays

The paperwork should decide what happens before emotions do. A clean break is easier when the shares are already tied to time. The standard schedule is four years with a one-year cliff, and 94% of founders and employees at startups backed by venture capital use it.

The cliff means nothing vests until the first year is complete, then the remaining shares vest over the rest of the schedule. If a founder leaves before the cliff, the unvested shares go back to the company. If a founder leaves after the cliff, the company keeps only the unvested portion. The shares follow the work, and the company does not lose control of shares it has not earned.

If the other person leaves after a short time, the company should not be left with a large unearned stake. That keeps a remaining founder from negotiating from a weak position.

Outside money shrinks the split but does not fix it

Founding teams kept roughly 56% of fully diluted equity after a seed round and roughly 36% after Series A, the next institutional round, once all potential shares are counted. The split you choose now will be smaller in percentage terms later, but it still sets the balance of power. A founder who starts with a larger share can still be outvoted later if the terms are bad. A founder who starts with a smaller share can still have a meaningful stake if the terms are fair.

A founder who feels the split was unfair before the round is likely to feel it after the round. The formation documents are the place to make the answer visible, because they are the version founders can point to later.

The formation documents are where the answer lives

Finish the checklist in a meeting. It holds the two decisions that prevent the most expensive argument: the split and the vesting terms.

• Start from 51/49, or write down why 50/50 is right. The median split for two-founder companies incorporated in 2019 was 60/40, and it shifted to 51/49 by 2023. Nearly half of two-person founding teams divide equity equally, and the equal-split share rose from 31.5% in 2015 to 45.9%.
• Put each founder on four-year vesting with a one-year cliff.
• State what happens to unvested shares if a founder leaves. Across 150+ departure cases, no vesting left the leaving founder with all of their equity in 65% of situations, and vesting was associated with clean breaks at triple the rate.
• Record the split and vesting terms in the formation documents before signing.

When the formation documents are ready, check the documents against the checklist. If the split and vesting terms are missing, stop the signing. Do not sign until the answer is in the file.