IONS Dark Pool Activity
Ionis Pharmaceuticals, Inc.
Data as of Oct 23, 2026 · Source: FINRA daily short sale volume (off-exchange)
On Oct 23, 2026, FINRA reported 1.1M IONS shares in publicly disseminated off-exchange trades (dark pools and other off-exchange venues). 453K of those shares (39.7%) were marked short or short-exempt, above IONS's 30-day rolling average of 33.7% (z-score 0.54). Over the last 10 FINRA sessions (Oct 12, 2026 – Oct 23, 2026), IONS's off-exchange short volume ratio ranged from 30.9% to 56.5% and averaged 43.2%; the latest reading is below that 10-session average.
Off-Exchange Volume
1.1M
Short Volume
453K
Short Volume Ratio
39.7%
30-Day Average
33.7%
z-score 0.54
Daily readings — last 10 FINRA sessions
| Date | Off-exchange shares | Short shares | Short ratio |
|---|---|---|---|
| Oct 12, 2026 | 689K | 251K | 36.4% |
| Oct 13, 2026 | 768K | 284K | 36.9% |
| Oct 14, 2026 | 680K | 385K | 56.5% |
| Oct 15, 2026 | 829K | 345K | 41.6% |
| Oct 16, 2026 | 567K | 234K | 41.3% |
| Oct 19, 2026 | 817K | 417K | 51.0% |
| Oct 20, 2026 | 911K | 449K | 49.3% |
| Oct 21, 2026 | 867K | 420K | 48.4% |
| Oct 22, 2026 | 2.5M | 762K | 30.9% |
| Oct 23, 2026 Latest | 1.1M | 453K | 39.7% |
Source: FINRA daily short sale volume (off-exchange). Ratio = ShortVolume ÷ TotalVolume for the day.
IONS dark pool FAQ
- How much IONS off-exchange volume did FINRA report on Oct 23, 2026?
- FINRA's daily short sale volume file reported 1.1M IONS shares in publicly disseminated off-exchange trades on Oct 23, 2026; 453K of those shares (39.7%) were marked short or short-exempt.
- Is IONS's dark pool short volume ratio unusual right now?
- As of Oct 23, 2026, IONS's short volume ratio of 39.7% is above IONS's 30-day rolling average of 33.7% (z-score 0.54). 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.