Co-founder split on a handshake? What to gather

Tellbrief · October 28, 2026

For education only. Not legal advice. Tellbrief is not a law firm.

If you started with a handshake, then when it’s time to write it down, your lawyer will want to know who owns what today, who built what and what each of you was promised.

Records to have ready

• Your formation documents and any founder stock agreements.
• Your cap table, even a rough one: who owns what share of the company.
• Any messages or notes where you agreed on the split, roles or vesting.
• A list of who holds the domain, code, accounts and other key assets.

Send them only if your lawyer asks. For the first call, knowing where each one is is enough.

Write down who did what

For each founder, note when they started, what they built or brought, what money they put in and how much time they give the business now.

Note the dates

Federal tax law says an election under section 83(b) “shall be made not later than 30 days after the date of such transfer.”¹ Ask your lawyer or tax adviser whether that applies to you, and write down when each founder got their stock, if they have.

Questions worth asking your lawyer

• What should the founders put in writing about who owns what, and what happens if one leaves?
• What should move from a founder’s name into the company’s name, and how?
• Should founder stock vest, and over what period?
• What happens to a founder’s share if they stop working on the business?

Tellbrief adds questions like these to your brief when your answers point to them.

For education only. This article is general information for founders, not legal advice, and reading it doesn’t make you anyone’s client. Tellbrief is not a law firm. For advice about your situation, talk to a licensed lawyer.