TRADING THEORY––Never answer a margin call because you are probably overtrading, and most likely, the position is going against you and you probably have lost much more than 2% on that trade. Never allow this to happen to you because you always want to have sufficient margin in your trading account just in case the exchange raises margin as that will force you out of the position.

A great rule is to keep 50% of your total portfolio in cash and the other 50% in trades, that way if something crazy happens and it does sometimes, this helps in managing risk in a huge way.