Short Interest
The number of shares sold short but not yet bought back, often shown as a percent of float.
Also called: short squeeze · days to cover
Written by Javier Sánchez Ros
In plain language
High short interest means many participants are positioned for a decline. Every one of them is a future buyer, because closing a short requires buying.
Days to cover estimates how long it would take short sellers to exit at average daily volume. High readings indicate a crowded, hard-to-exit position.
A short squeeze happens when rising prices force short sellers to buy back, which pushes prices higher and forces more buying. These moves are fast and detached from fundamentals.
Worked through
Short interest at 22% of float, and the squeeze mechanism
- Short interest
- 22% of float
- Days to cover
- 6.4
- Shorts must buy to exit
- always
- Buying pushes price
- higher, forcing more
Every short position is a future buy order. When 22% of the float is sold short and it would take six days of normal volume for those positions to close, that is a very large quantity of guaranteed future demand sitting above the market.
A squeeze is what happens when it arrives at once. Price rises, the earliest shorts buy to cover, that buying pushes price higher, which forces the next tier to cover, and so on. The move feeds itself and has nothing to do with the company — the fundamental case for the short can be entirely correct while it happens.
Stops handle this badly because squeezes gap. Price does not walk up through your level politely; it jumps, often at the open, and the buy-stop fills well above where it was set on a position whose losses are already unbounded.
High short interest is therefore not the confirmation it looks like. It tells you many people agree with your thesis, and that their agreement is stored as fuel for a move against you.
Why it matters
Shorting a heavily shorted stock carries squeeze risk that ordinary stop placement handles poorly, because squeezes gap through levels.
Common mistakes
- Treating high short interest as a reason to buy on its own.
- Shorting a crowded name with a tight stop that a squeeze will leap over.
Keep exploring
These concepts are connected. Understanding one usually makes the next one easier.
A position that profits when the price falls.
The number of shares actually available for public trading.
How easily an asset can be bought or sold without moving its price.
A jump between one period’s close and the next period’s open with no trading in between.
How much and how quickly an asset’s price moves over a given period.