Short interest data, live.
Exchanges publish short interest twice a month, roughly seven business days after the positions settle, so the official print is up to four weeks old by the time the next one arrives. ORTEX models it from securities-lending data and updates the estimate through the trading day, alongside the cost to borrow (borrow fee), availability, utilization and days to cover. These are the estimates professional desks work from and the financial press quotes.
The metrics, defined
Shares sold short as a percentage of the free float, the shares actually available to trade. ORTEX estimates it from securities-lending data and updates it through the trading day, instead of waiting for the twice-monthly exchange snapshot.
The annualized fee to borrow shares for short selling. A rising borrow fee means the lending market is tightening; an expensive borrow makes shorts costly to hold.
Shares still available to borrow, relative to shares already borrowed. As availability dries up toward zero, new shorts cannot be opened and existing shorts get harder to maintain, a classic squeeze ingredient.
The share of lendable stock currently out on loan. High utilization plus a rising borrow fee is a crowded short.
Short interest divided by average daily volume: roughly how many trading days short sellers would need to buy everything back.
Reading a squeeze setup
The ingredients tend to appear together: high short interest as a percentage of free float, shrinking availability, expensive borrow and high days to cover. When a catalyst hits a stock in that state, short sellers all need the same exit at the same time. ORTEX data made that setup visible before the Beyond Meat squeeze in October 2025, when Reuters cited ORTEX estimates of short interest above 100% of the public float.
Short interest and borrow figures are ORTEX estimates produced by our models, not exchange or regulatory filings. Estimates revise as new lending data arrives.
How fast a short squeeze moves
Faster than the official data. GameStop went from about $17 to an intraday $483 in under three weeks in January 2021, starting from short interest that the SEC’s own staff report later put above 100% of the public float. The whole move fit inside a single twice-monthly reporting cycle.
AMC did it twice the same year. In January 2021 the shares ran from about $2 to $20 in three weeks. The June echo was faster still: from roughly $12 to an intraday $72.62 in seven trading sessions, a move that cost funds on the short side more than a billion dollars in a single week.
The record belongs to Volkswagen in October 2008. Porsche disclosed control of about 74% of the shares on a Sunday; with the state of Lower Saxony holding another 20%, short sellers sitting on roughly 12% of the stock were left chasing a free float of about 6%. The price went from around €210 to an intraday €1,005 in the two trading days that followed, briefly making Volkswagen the most valuable company in the world. That is the five-fold move sketched in the chart above.
None of those moves waited for an exchange print. Live estimates are the only way to see the setup while it is still building, and the unwind while it is still tradeable.
On the platform, in your code, in your models
Everything on this page is live on the ORTEX platform and ships raw over the REST API, Python SDK and Excel add-in, from single-stock queries to full-universe bulk files.
And the data earns its keep beyond squeeze watching. Our Short Momentum Stock Score trading model, built partly on this short interest data, returned 2,545% over the last 16.51 years, against 789% for the S&P 500 Total Return. That is 3× the index, compounding at 21.9% a year.
Get the same data your desk quotes.
Live short interest on the platform, over the REST API and Python SDK, or straight into Excel. Start free, no card required.
See also: Stock Scores, Index Rebalance forecasts and the ORTEX API.