When people evaluate stocks, they look to the upside and determine how far it can go. Using data they hear from reports or looking at a stock chart, they are trying to figure out what will propel the company further. However, there is the flip side to the equation that the average investor may not know, and that is the ability to short a stock. Shorting a stock is when you borrow the shares from your broker, sell them to the market, hoping to buy back at a lower price and return them to the broker, keeping the difference. Shares that are being shorted could indicate people are seeing indications the company stock could be pulling back.