If you are monitoring the trades in realtime all you are looking at is the name of the broker used to run the trade.
If you CIBC, TD, etc on a buy or sell it just means that whoever ran the trade is using that bank / broker. It does not literally mean CIBC is trading on the stock.
Keep in mind banks do not trade 10's or 100's of shares, those trades are more likely retail investors. Banks and institutions deal in 100's of thousands or more of shares.
If you watch the volume indicator on the globe and mail quote page you can get a feel for the size of each trade. Their charts also show volume with the bar indicators on the bottom of the chart page.
Be mindful of seeing a large buy followed a small sell that resets the running shareprice back down.