MAS Dark Pool Activity
ATS off-exchange volume intelligence · Week of 2026-07-20
MAS dark pool volume for the week of 2026-07-20: 2.3M shares traded across 25 ATS venues with a total notional value of $181.3M. Volume is down 16.1% week-over-week. Primary routing venues include , INTELLIGENT CROSS LLC, UBS ATS.
Dark pool activity in MAS 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 MAS.
Weekly History
| Week | Shares | DP % | WoW |
|---|---|---|---|
| 2026-07-20 | 2.3M | — | -16.1% |
| 2026-07-13 | 2.8M | — | +6.5% |
| 2026-07-06 | 2.6M | — | +4.7% |
| 2026-06-29 | 2.5M | — | -3.4% |
| 2026-06-22 | 2.6M | — | +8.6% |
| 2026-06-15 | 2.4M | — | -7.6% |
| 2026-06-08 | 2.6M | — | -12.5% |
| 2026-06-01 | 2.9M | — | +16.7% |
| 2026-05-25 | 2.5M | — | -25.4% |
| 2026-05-18 | 3.4M | — | -23.8% |
| 2026-05-11 | 4.4M | — | +24.1% |
| 2026-05-04 | 3.6M | — | +2.7% |