Hello, I am new here and there is somthing I don't understand. Why is losing $500 better than losing a higher margin amount such as $2500? What do I miss?
Well if that were the case -- which it is not -- the answer would be obvious: Losing less is better than losing more!! Your margin requirement has nothing to do with how much you stand to win or lose. You are responsible for the totality of a loss even if it exceeds the amount in your account. Think of margin as a deposit that assures the broker that he has your money on deposit to cover a loss.
If you have the capital it can pay to trade with firms with high margin requirement because they can be better capitalized themselves and even too big too fail.