Days to Cover

Days to cover (also called the short interest ratio) is calculated by dividing the total short interest by the average daily trading volume. It represents how many days it would take for all short sellers to close their positions.

What this tells you

Short interest divided by average daily trading volume — an estimate of how many trading days it would take for every short position to be closed out at recent volumes. Sometimes called the short interest ratio.

What it does not tell you

Both inputs are older than they look. Short interest is reported on a twice-monthly schedule with a reporting lag, and average volume is by definition backward-looking, so the figure describes a market that has already moved on. It also tells you nothing about why anyone is short — a hedge against a convertible bond and a bet against the business produce the same number. And it does not predict a squeeze. It describes a condition, not an outcome.

Further reading: Wikipedia