Short interest.

In plain English

Short interest is the total quantity of a company's shares that have been borrowed and sold with the obligation to return them later. Exchanges collect and publish the figure on a regular schedule, so it is always somewhat stale by the time you see it. It is often quoted as a percentage of the freely tradable float, which is more meaningful than the raw count because it scales with company size. High short interest signals that many traders are positioned against the stock, but it says nothing about whether they are right. It also identifies the pool of buyers who will eventually have to close out.

01Why it matters

Short interest tells you how crowded a bet against a stock is, which shapes how violently the price can move in either direction when the news finally lands.

02The math, step by step

Say a company has 50 million shares in its float and 9 million shares sold short. Short interest is 18 percent of float. If the float were 200 million with the same 9 million short, it would be 4.5 percent, a very different picture from the same raw number.

Illustrative example. The amounts here are hypothetical, chosen to show how the math works, not real quoted rates or figures.

03What this is NOT

04Receipts

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