We'll find out soon enough if CIBC started buying everything in sight after 2:30pm today because of a leak, short covering or looking for a big block of shs in this price range. Maybe just a technical bump. 

Who's the market maker in this stock? I would think it's a house with the biggest consistent volumes. CIBC would definitely be one.

 https://www.tsx.com/trading/toronto-stock-exchange/order-types-and-features/market-maker-program/market-makers-list