MCO dark pool volume
FINRA weekly ATS volume · per dark pool · MCO off-exchange context · 8-week trend
Weekly FINRA data, published on a delay. Week shown: Sep 28 to Oct 2, 2026. FINRA first published this week's NMS Tier 1 file on Oct 19, 2026, 17 days after the week ended. These are the newest weekly numbers FINRA has published, not a live feed.
In the week of Sep 28 to Oct 2, 2026, MCO traded 1.9M shares in dark pools (FINRA-reported alternative trading system volume) across 30 dark pools, the largest was UBS ATS with 298.0K shares, dark pools carried 68% of its 2.7M FINRA-reported off-exchange shares. FINRA first published this week's file on Oct 19, 2026.
Latest week by dark pool
MCO dark pool volume, week of Sep 28 to Oct 2, 2026
| Dark pool | Shares | Trades | Share of MCO dark pool volume |
|---|---|---|---|
| UBS ATS | 298.0K | 11,335 | 15.9% |
| SIGMA X2 | 221.2K | 12,360 | 11.8% |
| INTELLIGENT CROSS LLC | 214.0K | 8,524 | 11.4% |
| INSTINCT X | 188.3K | 4,642 | 10.0% |
| LEVEL ATS | 130.9K | 4,704 | 7.0% |
| MS POOL (ATS-4) | 96.4K | 1,166 | 5.1% |
| ONECHRONOS | 87.0K | 2,498 | 4.6% |
| MS TRAJECTORY CROSS (ATS-1) | 86.8K | 8,926 | 4.6% |
| BIDS ATS | 80.6K | 341 | 4.3% |
| THE BARCLAYS ATS | 67.7K | 1,499 | 3.6% |
| POSIT | 59.3K | 539 | 3.2% |
| JPB-X | 58.4K | 1,937 | 3.1% |
Top 12 of 30 reported dark pools, covering 100% of the FINRA dark pool total.
Weekly trend
MCO dark pool volume history
| FINRA week | Dark pool shares | Non-ATS off-exchange | Dark share of off-exchange |
|---|---|---|---|
| Sep 28, 2026 to 2, 2026 | 1.9M | 865.5K | 68% |
| Sep 21, 2026 to 25, 2026 | 1.2M | 415.6K | 74% |
| Sep 14, 2026 to 18, 2026 | 956.0K | 680.5K | 58% |
| Sep 7, 2026 to 11, 2026 | 792.7K | 411.0K | 66% |
| Aug 31, 2026 to 4, 2026 | 1.2M | 434.6K | 73% |
| Aug 24, 2026 to 28, 2026 | 922.3K | 455.7K | 67% |
| Aug 17, 2026 to 21, 2026 | 1.2M | 547.5K | 68% |
| Aug 10, 2026 to 14, 2026 | 881.7K | 539.7K | 62% |
Dark pool volume is up 60.3% versus four weeks earlier (Aug 31, 2026).
Off-exchange context
Dark pools are one half of off-exchange trading. In the week of Sep 28 to Oct 2, 2026, FINRA reported 2.7M MCO shares traded off the exchanges in total: 1.9M through dark pools and 865.5K through the non-ATS channel (internalizers and wholesale market makers reporting straight to FINRA). Dark pools carried 68% 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 MCO 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
MCO stock page · Live MCO chart · Dark pool tracker · What is a dark pool (glossary) · Data methodology · All tickers: dark pool hub
FAQ
How much MCO volume trades in dark pools?
In the week of Sep 28 to Oct 2, 2026, MCO traded 1.9M shares in dark pools (FINRA-reported alternative trading system volume) across 30 dark pools, the largest was UBS ATS with 298.0K shares, dark pools carried 68% of its 2.7M FINRA-reported off-exchange shares. FINRA first published this week's file on Oct 19, 2026.
Which dark pools trade MCO?
In the week of Sep 28 to Oct 2, 2026, UBS ATS was the largest dark pool for MCO with 298.0K shares, out of 30 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 28 to Oct 2, 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.