Yes absolutely. sorry i just read this now but you should have called your firm and they should have eaten the loss in excess of your buying power. This happened to me once, i went 200000 long once instead of 2000, which 2000 would have used us the rest of the buying power. The clearing firm, software company etc, either had that trade broken (which actually moved the market in my stock for about 15 minuetes) or they just ate the loss. You should have pressed your firm to handle this, they have in many other cases. What good is a buying power limit if it can ONLY hurt you and not help you? It is, foremost, supposed to prevent errors of this sort. I would expect and fight to get that money back. Don't let your firm or the clearing firm bs you about it. If they start moaning about it....you can mention regulators etc..and that ususally starts the ball rolling. best of luck