Short Interest

ORTEX has estimated short interest every trading day since 2018. Official figures arrive twice a month and around eleven days late. ORTEX publishes a daily estimate for more than 52,000 securities before the US open, updates it through the session, and puts a range around it wherever official figures exist. Cost to borrow, utilization, days to cover, availability and the positions disclosed to regulators sit alongside it, so the whole short side of a stock is one dataset.

At a glance

• 52,700+ securities with a daily estimate
• 2018 daily history from
• 16,900 US securities re-estimated intraday
• Pre-open complete daily file, before the US open

95% of ORTEX estimates were within one percentage point of free float of the official figure, across 2.1 million official prints in the US, Canada, Australia and Hong Kong since August 2023.

Measured against every exchange-reported settlement figure. Estimate frozen before the official print.

What you can do with it

• Risk and crowding. See squeeze risk building on longs and shorts, weeks before the official print.
• Systematic signals. Daily, point-in-time short data since 2018 for factor and event research.
• Borrow and sizing. Cost to borrow and availability to size, finance and time a short.

The whole short side, in one dataset

Every number a short book, a risk desk or a squeeze screen needs, on one row per stock per day.

• Estimated short interest. Shares short every day, as a percentage of free float and in dollar value, with an upper and lower bound where official figures exist. A daily read between official report dates.
• Intraday updates. Short interest re-estimated through the session as lending moves, for around 16,900 US securities, with a live snapshot for any stock.
• Cost to borrow. The ORTEX cost to borrow for new loans and for all loans. The clearest single measure of how hard a stock is to short, and when that is changing.
• Utilization and availability. Shares on loan, the share of lendable supply in use and its daily change, and the shares still available to borrow.
• Named short positions. More than 590,000 positions disclosed to 14 regulators in Europe, the UK and Japan since 2003: who is short, how much, and since when.
• Short Score and days to cover. Days to cover over four volume windows, and one 0 to 100 score that ranks a whole market by short-side pressure.

Facts

Why ORTEX

Official short interest is late and infrequent; lending data on its own is noisy. ORTEX combines both into one daily estimate with a plausible range, removes dividend-driven lending that is not short selling, and scores itself against every official print.

Estimate vs official print

The daily ORTEX estimate against every official FINRA figure for one US stock through a fourfold rise in short interest.

Beyond Meat (BYND): shares short, millions. The line was published every morning. Each dot is the official figure, which arrived around eleven days after its settlement date. The chart is in the brochure PDF.

September 2025 to July 2026, before the company's 2026 reverse split.

While short interest in BYND quadrupled, the ORTEX line showed each step up to two weeks before the official figure.

Documents and API

• Download the brochure (PDF)
• Short Interest on public.ortex.com
• The full ORTEX data catalog (PDF)
• Enterprise API reference: Short interest per stock, Whole market by date, Cost to borrow
• Guide: Short Interest Metrics Explained
• Guide: How Short Interest Is Reported Around the World

Coverage, history and figures are as at November 2026. Provided for information purposes only; not investment advice, a personal recommendation, or an offer to buy or sell any security. Past performance is not a guide to future results. ORTEX does not guarantee the accuracy or completeness of any data or forecast. Trial access, pricing and licensing: [email protected].