Dark pools — formally Alternative Trading Systems, ATS — are venues where institutional traders execute large orders without revealing their intent to the public order book. They are regulated by the SEC and reported to FINRA, which publishes daily aggregate volume figures roughly two weeks in arrears.
Dark-pool volume itself is not directional — it does not tell you whether the institution was a buyer or a seller. What it does tell you is that institutional positioning is active. When combined with the DIX dealer-flow proxy and a corroborating signal like the VPIN-inspired toxicity score, dark-pool activity becomes part of a coherent institutional read.
How ChartGEX surfaces it
ChartGEX pulls FINRA ATS daily aggregates, normalizes them against trailing volume, and surfaces both per-ticker dark-pool levels and aggregate index figures. Extended-hours volume is tracked separately as a weaker signal.