MASS Dark Pool Activity

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

MASS dark pool volume for the week of 2026-07-06: 237.2K shares traded across 25 ATS venues with a total notional value of $1.9M. Volume is up 28.2% week-over-week. Primary routing venues include , MS TRAJECTORY CROSS (ATS-1), LEVEL ATS.

Dark pool activity in MASS 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 MASS.