Dark pool volume, explained
A dark pool is a private venue where institutions trade without posting their orders to a public order book. The trades still print — they are reported to the tape after execution — but the intent is hidden while the order is being filled.
Why institutions use them
A pension fund buying two million shares on a lit exchange would move the price against itself before the order finished. Routing through a dark pool lets the order fill closer to the prevailing price. This is legal, regulated, and routine — roughly 40% of US equity volume executes off-exchange on a normal day.
What the percentage actually measures
Dark pool share is off-exchange volume divided by total volume for that ticker, for that session. It is a ratio, not a direction: a high number tells you size traded quietly, not whether it was buying or selling.
How to read it
Around 40% is ordinary. Sustained readings well above that on a single name mean unusual institutional participation — worth pairing with options positioning to guess at direction. A single high day proves nothing; a run of them alongside a rising call wall is a different story.
The honest limitation
Off-exchange prints do not carry a buy/sell flag you can trust. Anyone selling you a "dark pool buy signal" is inferring direction from data that does not contain it. We show the share and let you combine it with positioning yourself.
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