A friend of mine is trading with IB and doing well. Recently IB has canceled his several successful transactions. First time they called and suggest either to cancel transaction or execute it with worth price. He lost $1000 because of this. Next time they canceled transactions without any warnings. Here is their email with explanations: "GENERAL ERROR TRADE INFORMATION In order to promote a fair and orderly market in which to trade, exchanges often make decisions to allow or disallow trades based on a number of factors. The exchanges each have their own guidelines that are used in evaluating executions, some of which are made public AND SOME ARE NOT. Currently the exchanges operate as "Self Regulatory Organizations" or SRO's, which gives them the authority to make such decisions." So my questions are: Does they has a right to do so? How it is possible to trade Forex with IB or any other broker, if the will allow you to loose generously and will cancel your successful transaction when you will win?