If no vesting was set up when ownership was divided, you technically own a third of the company. However if there was some implied agreement, or you want to be

If no vesting was set up when ownership was divided, you technically own a third of the company. However if there was some implied agreement, or you want to be fair, it makes sense to give back some of the equity. I think it's reasonable to keep more than a third of your portion though. The biggest risk in working on a startup is before it's raised (significant) funding when it's worth 0$. If you're actually raising another round soon, you've together brought it from a valuation of $0 to $2M. This was the highest risk time, so without a vesting agreement you may 'deserve' more than a third of your third, e.g. half of the third. It would be good to consult a lawyer though.