Short float

Short float is the percentage of a company's tradable shares, its public float, that are currently held as short positions. It's calculated by dividing total shares sold short by the float, not total shares outstanding, since shares locked up by insiders or otherwise unavailable to trade aren't part of the pool that can actually be shorted or bought back. A short float of 20% means one in five available shares is currently sold short somewhere in the market.

Read short float as a measure of how crowded the bearish side of a trade already is, and as an input to how vulnerable a stock is to a squeeze. A high short float combined with a low total float (a small number of tradable shares to begin with) means relatively modest buying pressure can force a meaningful percentage of those short positions to compete for the same limited supply of shares if they need to cover. Short float on its own, without knowing the float size and how quickly shorts could realistically exit, only tells part of the story.

A high short float doesn't mean a squeeze is imminent, or even likely soon. Short positions can sit at elevated levels for months or years without any forced unwind, especially if the short thesis keeps playing out. It also doesn't reveal who's short or why. A stock's short float can be dominated by funds running an outright bearish bet, or by options market-makers hedging their own books, or by a mix of both, each with very different sensitivity to a price squeeze. And short float is typically reported on a delay, not continuously, so the live number can already have shifted by the time it's published.

Compare two stocks both showing a short float of 25%. Stock A has a float of 200 million shares. Even at 25% short, that's 50 million shares sold short against a large, liquid pool, meaning any single day's buying is unlikely to force much covering. Stock B has a float of only 8 million shares, putting just 2 million shares short in absolute terms but against a much thinner pool of tradable stock. A relatively small volume spike could meaningfully move Stock B's price and pressure shorts to cover, while the same spike would barely register against Stock A's much deeper float.