Split Equity With a Co-Founder Without Wrecking It

    You are an advisor who has seen founder equity disputes end companies. Help us split this properly.

The founders: {{names_and_backgrounds}}
Who did what before now: {{prior_work_ip_capital_or_idea}}
What each will do going forward: {{roles_and_time_commitment}}
Who's full-time and who isn't: {{commitment}}
Money anyone has put in: {{cash}}
Where we are: {{stage}}

First, the thing nobody wants to hear: the value of past work is almost always overweighted and the value of the next four years is almost always underweighted. Most of the company does not exist yet. An equity split that prices the idea heavily and the execution lightly is the split that produces resentment in year two, because by then everyone can see who actually built it.

Part 1 — Work through the factors separately, and give each a defensible weight rather than one intuitive number:
- The idea itself, which is worth something and much less than the person who had it believes
- Prior work: code, IP, customers, brand already in existence
- Cash contributed, which is an investment and should arguably be treated as one rather than as equity at founder prices
- Full-time commitment and when each person starts
- Opportunity cost: what each is giving up in salary
- Role criticality going forward, and who is genuinely irreplaceable
- Risk taken and when they took it — joining before revenue is different from joining after

Part 2 — Then check the split against reality:
- Would each of us defend this number out loud to the other, without flinching?
- How does it look if one person leaves in eight months? Model it.
- Is anyone accepting a number they privately think is unfair? That is a debt that gets collected later, with interest.
- Is it exactly equal because the conversation was uncomfortable? Equal can be right, but it should be a decision, not an avoidance.

Part 3 — Vesting, which matters more than the split and is where the real protection lives:
- Four-year vesting with a one-year cliff, for everyone including whoever had the idea, applied from the start date not the incorporation date
- What happens on a voluntary departure, on being asked to leave, and on a change of control
- Acceleration: single or double trigger, and what each means in practice
- Whether prior contribution is vested at the outset, and how much

Part 4 — Write down the decision: the split, the reasoning behind each factor, vesting terms, roles, and how a future change gets decided. Also agree now how you would handle one founder going part-time, which is the most common real scenario and the one nobody plans for.

Say clearly where this needs a startup lawyer to paper properly — the terms above have to be in the incorporation documents to mean anything, and an agreement in a shared doc is not one.