Most cofounder fallouts are not about the number. They are about a conversation that never happened, papered over with a number that felt fair on a good day in a café. The split is the artifact; the missing conversation is the cause.1
The number is a symptom
When founders ask “is 50/50 a mistake,” they are asking the wrong question. A 50/50 split between two people who have actually said the hard things out loud is durable. A 60/40 split between two people who have not is a lawsuit with a head start.
“A fair split is not a number you agree on. It is a set of questions you can answer the same way, separately.”
Four questions before the split
Answer these alone, on paper, then compare. Where your answers diverge is exactly where the split is actually being decided.
- 01Who decides when we disagree, and on what? Name the domains — product, hiring, fundraising — and who holds the final call in each.
- 02What happens if one of us leaves in month nine? If the answer is not “their unvested equity returns to the company,” you do not have a split, you have a hostage situation.
- 03What are we each actually committing — capital, time, risk, network — and for how long? Write it down; memory is self-serving.
- 04What would make us renegotiate this, and how? A split that cannot be revisited will instead be resented.
Vesting is a feature, not an insult
Founders flinch at proposing vesting to each other, as if it signals distrust. It signals the opposite: a commitment to the people who do the work, and a clean answer to the month-nine question before it is asked in anger. The duos who set it up early almost never think about it again.2