ShortAtlas methodology
What short selling data means
A plain-English guide to short-selling activity, daily short-volume data, Short Interest, and the limits of public US market datasets.
Short selling is a position, short volume is trade flow
ShortAtlas separates daily reported short-volume activity from Short Interest. Daily short volume is trade-flow data from a reporting context, while Short Interest is a twice-monthly reported balance of open short positions.
A high daily short-volume percentage does not automatically mean a stock is heavily shorted. It can reflect market-making, hedging, intraday covering, or reporting context.
How to read a ticker page
Use the as-of date first. Daily short-volume data and Short Interest usually come from different publication cycles.
ShortAtlas is reference data only. It does not provide predictions, target prices, buy or sell signals, or investment advice.
Who appears in short-selling data
Reported short-sale volume is not limited to investors betting against a company. Market makers routinely sell short to fill buy orders and hedge inventory, and that activity is reported the same way as any other short sale.
Convertible bond arbitrage, index and ETF hedging, and merger arbitrage also generate short sales that have little to do with a directional view on a single company.
Where the published data comes from
Daily short-volume files are published by FINRA from trades reported to its facilities. They cover a reporting context rather than every share traded across all US market centers, so the totals are narrower than consolidated market volume.
Short Interest is collected from broker-dealer position reports on a twice-monthly settlement cycle and published after a processing delay, which is why the settlement date on a ticker page is always in the past.