You don't intend to work on this startup full-time? I'd say the current deal you have (10% for you, presumably 90% for the full time co-founder) sounds fair to

You don't intend to work on this startup full-time? I'd say the current deal you have (10% for you, presumably 90% for the full time co-founder) sounds fair to me. I have advised many founders in how to split equity. Think of it this way: if you had started at 50/50 each with the standard vesting, and you had quit early on (6 months to a year later), your 50% would turn into 6.25% to 12%. Pretty much exactly where you are now. I don't think you need to re-negotiate. Once your founder raises more money, you'll soon be diluted closer to 5%. Nothing that an outside investor would worry much about, unless they are not seasoned investors. Don't change anything.