Private trading venues among large institutions that do not show up in the regular market.
What these venues are
Dark Pools (Dark Pools) are private trading venues where trades execute with no visible order book: no one sees supply and demand before execution, and the trade is reported after it happens. They are legal, federally regulated, and host about a third of US stock trading.
Why they exist
To protect huge orders from themselves: a fund that wants to sell five million shares on the open market moves the price against itself as soon as its intent shows. Hiding it reduces the trade's impact on price and saves the retirees whose money the fund manages real millions. The function is legitimate, even if the name suggests otherwise.
What can be read from them
A symbol's dark-trading share and the locations of its large blocks: heavy dark activity at one price level draws a map of quiet institutional interest, the accumulation and distribution levels that do not show in the order book. The data arrives late and aggregated, so it is a map of positions, not a timing signal.
Hypothetical example
A stock oscillates around $85 and its dark volume swells at that level for two weeks in a row: a large player is building a position patiently where no one can see. The level becomes a reference. A break through it on volume says the accumulator has quit or has finished.
Common mistake
Reading every dark print as bullish accumulation: the published data carries no explicit direction (buy or sell?). Direction is inferred from where the trade printed between bid and ask, a probabilistic inference, not a certainty.
What the published data does not say
There is no explicit direction: was the block a buy or a sell? It is inferred from where the trade printed between bid and ask, a probabilistic inference, not a certainty. So read it as a map of areas of interest, not a timing signal, and back it with relative volume and price behavior at the same level.
Where to see it on the platform
The symbol card shows the share of off-exchange trading in its weekly volume, sourced from broker-regulator data, with the levels of the largest blocks.
The symbol card shows the share of off-exchange trading in its weekly volume, sourced from the broker regulator.
