Res,, I have had this happen to my-self on many ocassions. I recently contacted TD and was told a second Institution also had a sell order in, although the ask only showed 2 thousand shares my order for 26000 got filled at the ask price and then the next ask appeared at the same ask. I was told that this was not a ice-burg order. I have made hundreds of transactions on the CNQ in the last yr and have contacted TD brokers on several ocassions . They ( TD ) ALWAYS TELL ME THE SAME LINGO, AS THIS EXCHANGE IS AN UNREGULATED ex and your orders are subject to risk. I have expierenced the same on the tse as they call them ic-burgs or black pools. The game on the Greens will soon intensify as we see positions take hold, i will not just sit and act like a dumb pawn , as i prefer to be a knight. Long On The Greens Traps7