Here in the states the market makers on a given stock can see the stop loss orders that are in place for each stock. For a heavily traded stock, MMs regularly drop the trade price of a stock for milliseconds so they can pluck the stock sitting there with a stop loss order, and then the next trade happens at the previous market price for the day. Don't know if TSX MMs can do the same; but it looks to me that that is what happened today. CLose in stop losses are often just fancy orders to sell at a limit price.
Anyone got any view into the TSX mm family ?