CTSO dark pool volume
FINRA weekly ATS volume · per dark pool · CTSO off-exchange context · 8-week trend
Weekly FINRA data, published on a delay. Week shown: Sep 14 to 18, 2026. FINRA first published this week's NMS Tier 2 file on Oct 19, 2026, 31 days after the week ended. These are the newest weekly numbers FINRA has published, not a live feed.
In the week of Sep 14 to 18, 2026, CTSO traded 3.8K shares in dark pools (FINRA-reported alternative trading system volume) across 11 dark pools, the largest was UBS ATS with 757 shares, dark pools carried 18% of its 21.1K FINRA-reported off-exchange shares. FINRA first published this week's file on Oct 19, 2026.
Latest week by dark pool
CTSO dark pool volume, week of Sep 14 to 18, 2026
| Dark pool | Shares | Trades | Share of CTSO dark pool volume |
|---|---|---|---|
| UBS ATS | 757 | 36 | 20.1% |
| SIGMA X2 | 710 | 10 | 18.8% |
| INTELLIGENT CROSS LLC | 575 | 11 | 15.2% |
| LEVEL ATS | 471 | 9 | 12.5% |
| VIRTU MATCHIT ATS | 321 | 12 | 8.5% |
| THE BARCLAYS ATS | 313 | 7 | 8.3% |
| IBKR ATS | 216 | 3 | 5.7% |
| BIDS ATS | 200 | 2 | 5.3% |
| BNPP CORTEX ATS | 108 | 4 | 2.9% |
| JPM-X | 100 | 1 | 2.6% |
| CBX | 4 | 4 | 0.1% |
Weekly trend
CTSO dark pool volume history
| FINRA week | Dark pool shares | Non-ATS off-exchange | Dark share of off-exchange |
|---|---|---|---|
| Sep 14, 2026 to 18, 2026 | 3.8K | 17.3K | 18% |
| Sep 7, 2026 to 11, 2026 | 9.4K | 38.2K | 20% |
| Aug 31, 2026 to 4, 2026 | 247.2K | 4.6M | 5% |
| Aug 24, 2026 to 28, 2026 | 39.4K | 303.8K | 11% |
| Aug 17, 2026 to 21, 2026 | 60.0K | 526.0K | 10% |
| Aug 10, 2026 to 14, 2026 | 13.7K | 215.4K | 6% |
| Aug 3, 2026 to 7, 2026 | 12.0K | 247.1K | 5% |
Dark pool volume is down 93.7% versus four weeks earlier (Aug 17, 2026).
Off-exchange context
Dark pools are one half of off-exchange trading. In the week of Sep 14 to 18, 2026, FINRA reported 21.1K CTSO shares traded off the exchanges in total: 3.8K through dark pools and 17.3K through the non-ATS channel (internalizers and wholesale market makers reporting straight to FINRA). Dark pools carried 18% of that off-exchange total. This is a share of FINRA-reported off-exchange volume, not of total market volume; the FINRA weekly file does not include exchange volume.
How to read this
Dark pools are private alternative trading systems that match institutional orders without displaying them to the public first. The weekly FINRA file shows how many CTSO shares and trades each dark pool reported, aggregated for the whole week. It carries no prices, no trade sizes, and no direction, so it cannot say whether the volume was buying or selling. Use it to see where hidden liquidity concentrated, and pair it with the live chart for price context.
Related
CTSO stock page · Live CTSO chart · Dark pool tracker · What is a dark pool (glossary) · Data methodology · All tickers: dark pool hub
FAQ
How much CTSO volume trades in dark pools?
In the week of Sep 14 to 18, 2026, CTSO traded 3.8K shares in dark pools (FINRA-reported alternative trading system volume) across 11 dark pools, the largest was UBS ATS with 757 shares, dark pools carried 18% of its 21.1K FINRA-reported off-exchange shares. FINRA first published this week's file on Oct 19, 2026.
Which dark pools trade CTSO?
In the week of Sep 14 to 18, 2026, UBS ATS was the largest dark pool for CTSO with 757 shares, out of 11 dark pools that reported the ticker. The table above lists the rest.
Why is this data weeks old?
FINRA publishes dark pool volume weekly, on a delay. The week of Sep 14 to 18, 2026 was first published Oct 19, 2026, and nothing fresher exists until FINRA publishes the next week. We state the lag plainly instead of dressing delayed data up as live.
Does heavy dark pool volume mean big investors are buying?
No. Dark pool volume is hidden liquidity: it says where institutions chose to trade away from the lit exchanges, nothing about direction. FINRA reports share counts and trade counts, not prices, sizes, or sides. A week of heavy dark pool volume can accompany accumulation, distribution, or two-sided market making.