What Is Short Interest? Short Ratio Explained

Short interest is the total number of shares of a stock that have been sold short and not yet covered (bought back). It tells you how many investors are betting against a stock — that its price will fall.

How Short Selling Works

Short sellers borrow shares and sell them immediately, hoping to buy them back later at a lower price and pocket the difference. If the stock goes up instead, the short seller loses money and may be forced to buy shares back ("cover"), which pushes the price up further — the mechanism behind a short squeeze.

Key Short Interest Metrics

• Short Interest: Total shares sold short. Reported twice monthly by FINRA.
• Short Ratio (Days to Cover): Short interest ÷ average daily trading volume. Tells you how many days it would take all short sellers to cover at normal volume. A ratio above 5 is considered high.
• Short Interest as % of Float: Short shares as a percentage of shares available to trade. Above 10% is significant; above 20% is very high.
• Short Volume: Daily short selling activity. Changes day to day and reflects current sentiment shifts.

What High Short Interest Means

High short interest means a large number of investors expect the stock to decline. This can be a bearish signal — smart money is betting against the stock — or it can be a contrarian setup for a short squeeze if the stock starts rising.

Short Squeeze Potential

When a highly-shorted stock starts rising (due to good news, earnings beat, or a change in sentiment), short sellers are forced to buy shares to cut their losses. This surge in buying pushes the price higher, forcing more short sellers to cover — a feedback loop. See the Short Squeeze Rankings.

How to Use Short Interest Data

Short interest is most useful when combined with other signals. A stock with high short interest and a low RSI reading may be a short squeeze candidate. A stock with rising short interest and deteriorating fundamentals may be genuinely at risk.

See the live Short Interest Rankings for S&P 500 and Nasdaq 100 stocks.