Base the ownership discussion on future contribution

A real cofounder accepts responsibility for the whole venture. That commitment differs from employment with shares as part of compensation. Do not use one label to conceal different expectations. Explain what each person must contribute and what they can reasonably expect in return.

Past effort alone does not determine future value. A long period of work on a weak product can matter less than the right person joining tomorrow. Consider the capability, risk, resources, and continuing commitment that each person brings. Also recognize what the business has already created.

Comparable continuing responsibility can support comparable ownership. Different roles and commitments can justify a different arrangement. No single percentage removes the need for judgment. The reasoning must be clear enough for everyone to accept without hidden resentment.

Distinguish ownership, salary, and decision rights. They affect one another, but they answer different questions. Document the arrangement with suitable professional help. Review its assumptions when a significant change makes them inaccurate.