how-short-sellers-beat-the-system - Recommended reading"It doesn’t take a lot of money to control a stock via short selling on the TSX Venture. As a matter of fact, institutions often hammer stocks via short selling and back up their shorts with warrants they obtained in a previous financing. They often force the price of a stock down to finance the same companies they’re shorting to get a better financing price, or to force a company into a financing arrangement.”
From one of the best articles I've seen regarding short selling in Canada. I recommend everyone read every word of it.
Rainyday, there's actually a term for 'painting the tape': What is Downticking?
Downticking is when a trader sells stock so that the most recent change in the share price is negative. This is usually done right before the market closes using very small amounts of stock.
And since stock charts only follow the closing price of a stock, you can see how easy it is for a short seller to create a nasty-looking downward chart by spoofing and down-ticking.
These practices are illegal but happen to many Canadian stocks.