CSTL Dark Pool Activity

ATS off-exchange volume intelligence · Week of 2026-07-06

CSTL dark pool volume for the week of 2026-07-06: 325.7K shares traded across 23 ATS venues with a total notional value of $7.8M. Volume is up 27.8% week-over-week. Primary routing venues include , MS TRAJECTORY CROSS (ATS-1), SIGMA X2.

Dark pool activity in CSTL reflects institutional order flow executing on Alternative Trading Systems (ATS) registered with the SEC — private venues where large-block trades are matched away from public exchanges to minimize price impact. StonkWhisper ingests FINRA-published ATS volume data to track these off-exchange flows. Sustained elevation in dark pool percentage — particularly when concentrated at specific venues — can indicate institutional accumulation or distribution ahead of significant price moves. The interactive charts below show 12-week historical volume and complete venue breakdown for CSTL.