FINRA Short Interest Data, Explained

Nearly every short-interest number you have ever read traces back to FINRA, the US broker-dealer regulator — and FINRA publishes two entirely different short-selling datasets that get conflated constantly. One is the short interest file: broker-reported open short positions, compiled twice a month. The other is the daily short volume file: a byproduct of trade reporting, published every day, measuring something else. This page explains both at the source level — the schedules, what each file contains, and the failure modes we have caught in the files themselves.

The twice-monthly short interest file

Broker-dealers report their customers' and their own open short positions to FINRA as of two settlement dates each month — mid-month and month-end — and the exchanges disseminate the compiled totals per security. That cadence is verifiable in the data:

SELECT toYear(settlement_date) AS year,
       uniqExact(settlement_date) AS settlement_dates
FROM global_markets.stocks_short_interest
WHERE settlement_date >= '2024-01-01' AND settlement_date <= '2026-06-30'
GROUP BY year
ORDER BY year

Twenty-four settlements a year — 24 in 2024, 24 in 2025 — landing on a published exchange schedule. Each record carries the position (shares short), an average-daily-volume figure, and the days-to-cover ratio built from them. Two properties matter more than anything in the file: it is a snapshot of open positions (the thing people actually mean by "short interest"), and it is slow — positions as of the settlement date, published roughly two weeks later. The lag has its own page, with the publication delays measured print by print.

The daily short volume file — the one that isn't short interest

Every day, FINRA publishes per-ticker "short volume": the portion of that day's reported off-exchange trades where the sell side was marked short. It is DAILY and fresh — and it is a flow, not a position. Market makers short constantly as routine inventory management, so marked-short percentages run high (often forty to sixty percent of volume) for utterly ordinary stocks on utterly ordinary days. Treating the daily file as fast short interest is the single most common short-data mistake on the internet; the two-datasets comparison takes it apart with a worked example.

The failure modes — receipts from our own archive

Reading a data source honestly means knowing how it breaks. In the last month our pipeline has caught the daily short-volume file arriving truncated twice — an alphabetical fragment of the usual ticker universe:

SELECT toString(date) AS d,
       uniqExact(ticker) AS tickers_on_file
FROM global_markets.stocks_short_volume
WHERE date IN ('2026-06-26', '2026-06-29', '2026-06-30', '2026-07-06', '2026-07-07', '2026-07-08')
GROUP BY date
ORDER BY date

June 29's file carried 5489 tickers against ~15052 on a normal day, and July 7's carried 4333 — both alphabetical truncations, both on newsworthy sessions, both flagged in our recaps when they happened. The practical rule: before quoting any single day's short volume for any ticker, check whether that day's file is complete. (The twice-monthly short interest file has its own failure mode — after-the-fact restatement. We have watched a young listing's settlement print revised several-fold upward weeks after first publication; pages here re-run their queries at every regeneration precisely so revisions surface instead of fossilizing.)

Which file should you use for what?

• "How shorted is this stock?" — the twice-monthly short interest file, read with its date. The most-shorted leaderboards are built from its latest print.
• "Are shorts pressing today?" — nothing public answers this cleanly. The daily file is the closest artifact and it mostly measures market-making plumbing; use it for patterns across days, never as a same-day position estimate.
• "When does new data arrive?" — settlements twice monthly on the exchange schedule, published on a lag; daily files each evening for the prior session.

FINRA short interest FAQ

How often does FINRA publish short interest?

Open short positions are reported as of two settlement dates per month — mid-month and month-end, twenty-four per year — and published roughly two weeks after each settlement. The daily short volume file is a different dataset, published every trading day.

Is FINRA short interest data free?

Yes — FINRA and the exchanges disseminate both files publicly. Most paid "short interest" products are repackaging (or estimating between) these same prints.

Why does short volume show 50% short when short interest is tiny?

The daily file marks the sell side of off-exchange trades, and market makers sell short constantly as inventory plumbing — it is a flow statistic dominated by intermediation, not a position statistic. The two numbers measure different things and routinely diverge by an order of magnitude.

Can FINRA short interest data be wrong?

It can be late, truncated, or restated — all three documented above from our own archive. Treat every print as "as reported, as of its date," and prefer sources that show which file and date a number came from.

Every panel is a stored, versioned query over the files themselves — expand the SQL, or audit any date's coverage on the Strasmore terminal.