How to Read a Short Interest Ratio

Short interest ratios can help investors recognize a stock's trend.

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Investors rely on a wide variety of analytical tools to formulate their predictions for upcoming market action. A “short interest ratio” is one such resource. Using the short interest ratio, an investor can quickly determine whether or not a stock is being disproportionately shorted relative to its fundamentals. This information, in turn, will provide strong indicators as to whether or not it may be the right time to buy.


A short interest ratio provides investors with an insightful overview of how many shorted shares have yet to be covered or closed. As the ratio increases, investors may think twice before entering a new short position.

Exploring the Basics of Short Interest Ratios

Fundamentally, a short interest ratio is a mathematical formula in which the number of shorted shares of a stock are divided by the average volume of daily trades. To fully understand the implications of this formula, it is first necessary to explore the process of short selling.

When an investor “shorts” a stock, they are selling a specific number of securities that they currently do not own in hopes that the price of the asset will eventually fall. When an investor borrows the shares from a broker in order to sell them, they will eventually be required to return them. If the investor was able to sell the shares at a high price point and then repurchase them for a significantly lower price, they will be able to realize a profitable gain after returning the shares to the original broker.

That being said, there is considerable risk involved in this type of transaction due to the fact that there is no guarantee that the price of the shares will decline. For example, if shares are shorted and the price increases, the investor will be required to buy back the securities they borrowed at the new, higher price. This opens the door for significant losses.

Distinguishing Between Short Volume vs Short Interest

It is easy to misuse various terms related to this particular analytical method. That being said, taking the time to properly understand how these particular ideas are distinguished from one another can help reduce risk and increase the likelihood of profitable gain.

Whereas the term “short volume” measures the number of shares that have been shorted over a given period of time, “short interest” represents the number of shorted shares that have yet to be closed out or covered by investors. Taking this one step further, the short interest ratio is used to assess how long it would take for all shorted shares currently in play to be covered. The larger the ratio becomes, the more outstanding shorted shares have yet to be closed.

This information could become particularly important for investors who may be considering entering a short position. With a large number of outstanding shorted shares that have not been closed, entering a new short position could create unnecessary risk.

Exploring Limitations of the Ratio

Although the short interest ratio does yield a variety of meaningful data, there are some limitations to this particular measurement. For example, a short interest tracker is only reported to investors every two weeks. Because of this, it is quite possible that the data may already be somewhat outdated by the time it reaches investors.

With that in mind, it is recommended that investors use the short interest ratio as a supplement to additional methods of analysis rather than as a sole prognosticator. This will help mitigate some level of risk over time and ensure that investors have all possible information to inform their trades.