COST Dark Pool Activity
COSTCO WHOLESALE CORPORATION
Data as of Oct 23, 2026 · Source: FINRA daily short sale volume (off-exchange)
On Oct 23, 2026, FINRA reported 589K COST shares in publicly disseminated off-exchange trades (dark pools and other off-exchange venues). 284K of those shares (48.3%) were marked short or short-exempt, above COST's 30-day rolling average of 46.0% (z-score 0.42). Over the last 10 FINRA sessions (Oct 12, 2026 – Oct 23, 2026), COST's off-exchange short volume ratio ranged from 40.5% to 56.8% and averaged 47.6%; the latest reading is above that 10-session average.
Off-Exchange Volume
589K
Short Volume
284K
Short Volume Ratio
48.3%
30-Day Average
46.0%
z-score 0.42
Daily readings — last 10 FINRA sessions
| Date | Off-exchange shares | Short shares | Short ratio |
|---|---|---|---|
| Oct 12, 2026 | 586K | 259K | 44.2% |
| Oct 13, 2026 | 467K | 206K | 44.1% |
| Oct 14, 2026 | 1.2M | 504K | 43.0% |
| Oct 15, 2026 | 1.2M | 479K | 40.5% |
| Oct 16, 2026 | 699K | 328K | 47.0% |
| Oct 19, 2026 | 632K | 327K | 51.8% |
| Oct 20, 2026 | 666K | 378K | 56.8% |
| Oct 21, 2026 | 490K | 253K | 51.6% |
| Oct 22, 2026 | 809K | 391K | 48.4% |
| Oct 23, 2026 Latest | 589K | 284K | 48.3% |
Source: FINRA daily short sale volume (off-exchange). Ratio = ShortVolume ÷ TotalVolume for the day.
COST dark pool FAQ
- How much COST off-exchange volume did FINRA report on Oct 23, 2026?
- FINRA's daily short sale volume file reported 589K COST shares in publicly disseminated off-exchange trades on Oct 23, 2026; 284K of those shares (48.3%) were marked short or short-exempt.
- Is COST's dark pool short volume ratio unusual right now?
- As of Oct 23, 2026, COST's short volume ratio of 48.3% is above COST's 30-day rolling average of 46.0% (z-score 0.42). 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.