Raising money
Co-founder equity split
A co-founder equity split is how the founders divide ownership of the company between them, usually agreed when the company is set up.
Also called founder equity split, equity split, co founder equity
Looking this up for a class, a job, or something you want to build? If it is the last one, nommi reads your idea before you spend months on it.
There is no standard split. Founders weigh who had the idea, who works full time, who brings money or skills, and who will carry the most work ahead. Founder shares usually vest over time, so a founder who leaves early keeps only part of them. The split goes on the cap table and is hard to change later.
This is not legal or tax advice, check with a lawyer or accountant.
What recent Carta data says
In Carta data, the lead founder of a team, meaning the co-founder with the largest stake, held a median 27% at a priced seed round in 2024, against 52% for a solo founder.
- Median lead founder stake at a priced seed round, team against solo founder (2024 rounds): 27% against 52%.
- Median lead founder stake at exit, team against solo founder (exits 2019 to June 2025): 16% against 28%.
Source: nZero Labs with Carta data, State of Solo Founders 2025. Companies on Carta, not the whole market. A smaller stake is not a reason to found alone: a team shares the work as well as the company. As of 5 November 2026.
When this shows up
Example, not a real founder: two friends split ownership evenly over coffee and sign nothing. Months later one stops working on the company but still owns half, and every investor who reads the cap table asks why.
What to do next
Before writing any code together, agree in writing on the split, the vesting schedule, and what happens to unvested shares if someone leaves. Have a lawyer turn it into the company's documents.
Questions founders ask
How do we split equity between co-founders? Start from the work ahead, not only the idea: who works full time, who brings money or skills, and who will carry most of what is still to be built. There is no standard split, so put it in writing with vesting, and have a lawyer turn it into the company's documents.