IB has liberal leverage, low margin, low commissions and low fees. And it has come up again and again on ET, they will liquidate a portfolio in a heart beat, if an account hits one of their risk triggers. They offer you the leverage, and don't over charge with margin; but they will quickly liquidate (guess its automated) and won't ask for your opinion if that leverage becomes a risk to one's account. Personally, I don't have a problem with it; in fact its a good business practice on their end.. They are up front about it. Its not arbitrary. And a trader's account screen at any given moment shows, if things are getting close to this happening. They've probably saved traders tons of money by doing this. Limiting it to a major loss instead of a major ruin.