What to do in an equity disagreement in a startup
cmos: If there is a vesting period, perhaps negotiate that to be shorter.  Often times a founders shares will vest over time, so that if you quit in a month you don't retain an inappropriate amount of the company compared to the effort put in.  Since you are taking a 'hit', that could be a beneficial negotiation.  Read the paperwork.  Three times.  Make sure you understand every sentence.You are asking us because you feel like you've been taken.  You were told (promised?) that you would get 20%.  Now it's down to 16% because someone's a crybaby, and your the only one getting shorted.There's simply no right answer about what to do.  And that's the crappy part about starting a company.  Sometimes the rules change.  Sometimes people are mean.  Sometimes you get screwed.  Staying with the company could either be the smartest thing or the dumbest thing you ever do.  You asked for advice, so your not 100% on staying.  But that also means your not 100% on leaving.  So you see potential.If you really don't know, stay.  If it's fun, keep going.  If not, bail instantly.  This is your 'get out of jail free with no guilt' card.  Later on, if things are crappy, and you just want to leave, but everyone is depending on you to work for cheap and slug through it more, and you just don't see it going anywhere, or realize it's not fun, or it turns out these guys really are assholes (which hopefully would show itself sooner, if not now) and no, you don't want to spend every waking moment of your life with them, you can just quit.