FINRA short volume data showing stocks with the highest short volume percentage.
Unusual activity is flagged when short vol >50% and relative volume >1.5x.
Methodology note: This data shows FINRA-reported short volume, which is a commonly used proxy but is not identical to true dark pool volume. Short volume includes market maker activity and hedging. Data is delayed by one trading day.
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For informational purposes only. The data and visualizations on this page do not constitute financial advice, investment recommendations, or an offer to buy or sell any securities. Always do your own research and consult a qualified financial advisor before making investment decisions.
Here's the part of market structure that almost nobody talks about: roughly four out of every ten shares traded in the U.S. never touch a public exchange. They move through dark pools — private venues where big institutions can quietly work massive orders without tipping the tape. The whole reason they exist is that if a pension fund tried to buy five million shares of a stock on the NYSE, the price would run away from them before they got halfway filled. Dark pools solve that by matching large blocks anonymously, typically near the midpoint of the public spread. The orders themselves stay invisible until the trade is already done.
FINRA requires all off-exchange venues (including dark pools, ATSs, and internalizers) to report daily short volume. This data shows what percentage of total off-exchange volume was executed as short sales. A high short volume percentage does not necessarily mean bearish positioning—market makers routinely sell short as part of their order-filling process and hedge immediately. However, persistent or unusual short volume, especially combined with high relative volume, may reflect institutional positioning.
The ratio of short volume to total volume reported through off-exchange venues. A baseline of 40–50% is normal due to market-making activity. Readings above 55% are sometimes noted by traders, and above 65% may reflect elevated short activity.
This compares the current day's volume to the stock's average volume over the prior 20 days. A relative volume above 1.5x means 50% more shares are trading than normal. When combined with high short volume, it suggests unusual institutional activity that may be worth monitoring.
Yes. FINRA publishes short volume data with a one-trading-day delay. The data you see on our tracker reflects the previous trading session. This delay is built into the regulatory reporting schedule and applies to all data providers.
Not necessarily. Market makers frequently sell short as part of normal order-filling and hedge their positions immediately. A baseline short volume of 40–50% is standard. Only persistently elevated readings well above 55%, especially with unusual relative volume, are sometimes noted as unusual.
We flag stocks as “unusual” when two conditions are met simultaneously: short volume exceeds 50% of total volume AND relative volume is above 1.5x the 20-day average. This combination filters out normal market-making noise and highlights stocks where something atypical may be occurring.
Institutional investors managing large portfolios need to trade millions of shares without alerting the market. If they placed a large order on a public exchange, other traders would front-run them, driving the price up before the institution could finish buying. Dark pools provide anonymity and minimize market impact for these large block trades.
