Short interest is the total number of a stock's shares that have been sold short and not yet closed out. It's reported by exchanges (FINRA/Nasdaq) roughly twice a month for US-listed stocks — public, verifiable data, not an estimate.
The two numbers that actually matter
- Short interest as % of float — how much of the tradeable supply is currently shorted. Above ~10-15% starts to be considered elevated, though this varies a lot by stock.
- Days to cover — short interest divided by average daily volume. A high days-to-cover means it would take shorts several days of average trading to close their positions if they all tried at once — the core ingredient in a short squeeze.
What it doesn't tell you
Short interest is a snapshot, updated roughly twice a month, not a live feed — positions can change significantly between reports. It also doesn't tell you WHY a stock is heavily shorted (could be a genuine bearish thesis, a hedge against a long position elsewhere, or an arbitrage strategy) — high short interest alone isn't automatically bullish or bearish, it's a magnitude indicator that matters most alongside price action and volume.
Where Quantora fits
Quantora's Short Interest section pulls current short interest, days-to-cover, and the period-over-period change for any US-listed stock — free, sourced from Nasdaq's public data, right on the same Stock Intelligence page as technicals, ownership, and insider activity.