Short interest ratio

The short ratio (or short interest ratio) is usually the number of shares outstanding of a publicly traded company that is sold short, divided by the average daily trading volume (daily transaction). It can also be the percentage of the free float that is "shorted".It is one measure of the market's outlook on a given stock; a higher short interest ratio indicates more pessimism, because a higher proportion of a company's total float has already been sold short. The short interest and short ratio can be deceiving, however, when a company has many convertible securities outstanding and is perceived to be at risk, because convertible and options arbitrageurs will often sell the stock short to manage risk with their long positions in these other instruments.
See more at Wikipedia.org...

This is the ratio number of shares of a security that investors have sold short divided by average daily volume of the security (measured over 30 days or 90 days). There are various interpretations of this ratio. When people short, that is usually (but not always) because they are pessimistic about the security's future performance. However, when you short, at some point, you need to purchase. Hence, some would interpret a large short ratio as an indicator that there will be some buying pressure on the security which would increase its price.