MLM Dark Pool Activity
Martin Marietta Materials, Inc.
Data as of Oct 23, 2026 · Source: FINRA daily short sale volume (off-exchange)
On Oct 23, 2026, FINRA reported 280K MLM shares in publicly disseminated off-exchange trades (dark pools and other off-exchange venues). 204K of those shares (72.8%) were marked short or short-exempt, above MLM's 30-day rolling average of 55.4% (z-score 1.52). Over the last 10 FINRA sessions (Oct 12, 2026 – Oct 23, 2026), MLM's off-exchange short volume ratio ranged from 36.2% to 72.8% and averaged 55.8%; the latest reading is above that 10-session average.
Off-Exchange Volume
280K
Short Volume
204K
Short Volume Ratio
72.8%
30-Day Average
55.4%
z-score 1.52
Daily readings — last 10 FINRA sessions
| Date | Off-exchange shares | Short shares | Short ratio |
|---|---|---|---|
| Oct 12, 2026 | 228K | 97K | 42.8% |
| Oct 13, 2026 | 302K | 109K | 36.2% |
| Oct 14, 2026 | 434K | 188K | 43.3% |
| Oct 15, 2026 | 479K | 295K | 61.5% |
| Oct 16, 2026 | 447K | 287K | 64.3% |
| Oct 19, 2026 | 380K | 194K | 51.0% |
| Oct 20, 2026 | 389K | 244K | 62.7% |
| Oct 21, 2026 | 205K | 138K | 67.3% |
| Oct 22, 2026 | 365K | 204K | 56.0% |
| Oct 23, 2026 Latest | 280K | 204K | 72.8% |
Source: FINRA daily short sale volume (off-exchange). Ratio = ShortVolume ÷ TotalVolume for the day.
MLM dark pool FAQ
- How much MLM off-exchange volume did FINRA report on Oct 23, 2026?
- FINRA's daily short sale volume file reported 280K MLM shares in publicly disseminated off-exchange trades on Oct 23, 2026; 204K of those shares (72.8%) were marked short or short-exempt.
- Is MLM's dark pool short volume ratio unusual right now?
- As of Oct 23, 2026, MLM's short volume ratio of 72.8% is above MLM's 30-day rolling average of 55.4% (z-score 1.52). Meridian's dark pool model does not flag this reading as an anomaly.
- What does the dark pool short volume ratio measure?
- FINRA publishes daily short sale volume for trades reported off-exchange to its trade reporting facilities, which include dark pools and other off-exchange venues. The ratio divides FINRA's ShortVolume figure, which counts both short and short-exempt sales, by the total off-exchange shares reported for that day. It is not short interest and not a directional signal: market-maker hedging and reporting mechanics can raise it, so it is context for other signals.