Nowhere did I say to be unreasonable, aggressive, or rude. Just that being kind and compassionate is not what you need to be. As you say, "an immovable wall", w

Nowhere did I say to be unreasonable, aggressive, or rude. Just that being kind and compassionate is not what you need to be. As you say, "an immovable wall", which is hardly kind or compassionate. By "nice", if you mean polite, of course. By "nice", if you mean kind and compassionate (reiterating those adjectives), no, unless you mean "polite" by those as well. "Helping the other co-founder get to the decision" is only going to be achieved with leverage given that it's clear they're not looking to find an equitable (hah!) solution. They're trying to get as much control and equity as possible. It may be the OP has no option but to accept it (keeping 3% and moving on). Or it may be the OP has better options. But the point is that the other party has made their intentions known. They haven't come to the negotiating table saying "This is what I want, how can I get you to agree", they've come to it with "This is what I want; accept it", and when provided what the OP wants in return, turned it down, rather than seeking some middle ground or otherwise budging.