MPC Dark Pool Activity
Marathon Petroleum Corporation
Data as of Oct 23, 2026 · Source: FINRA daily short sale volume (off-exchange)
On Oct 23, 2026, FINRA reported 584K MPC shares in publicly disseminated off-exchange trades (dark pools and other off-exchange venues). 234K of those shares (40.1%) were marked short or short-exempt, below MPC's 30-day rolling average of 56.8% (z-score -2.19). Over the last 10 FINRA sessions (Oct 12, 2026 – Oct 23, 2026), MPC's off-exchange short volume ratio ranged from 40.1% to 61.7% and averaged 54.5%; the latest reading is below that 10-session average.
Off-Exchange Volume
584K
Short Volume
234K
Short Volume Ratio
40.1%
30-Day Average
56.8%
z-score -2.19
Daily readings — last 10 FINRA sessions
| Date | Off-exchange shares | Short shares | Short ratio |
|---|---|---|---|
| Oct 12, 2026 | 531K | 321K | 60.4% |
| Oct 13, 2026 | 700K | 391K | 55.9% |
| Oct 14, 2026 | 748K | 351K | 47.0% |
| Oct 15, 2026 | 895K | 531K | 59.4% |
| Oct 16, 2026 | 676K | 415K | 61.3% |
| Oct 19, 2026 | 757K | 467K | 61.7% |
| Oct 20, 2026 | 750K | 444K | 59.2% |
| Oct 21, 2026 | 917K | 448K | 48.8% |
| Oct 22, 2026 | 864K | 443K | 51.3% |
| Oct 23, 2026 Latest | 584K | 234K | 40.1% |
Source: FINRA daily short sale volume (off-exchange). Ratio = ShortVolume ÷ TotalVolume for the day.
MPC dark pool FAQ
- How much MPC off-exchange volume did FINRA report on Oct 23, 2026?
- FINRA's daily short sale volume file reported 584K MPC shares in publicly disseminated off-exchange trades on Oct 23, 2026; 234K of those shares (40.1%) were marked short or short-exempt.
- Is MPC's dark pool short volume ratio unusual right now?
- As of Oct 23, 2026, MPC's short volume ratio of 40.1% is below MPC's 30-day rolling average of 56.8% (z-score -2.19). 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.