Ionis Pharmaceuticals
IONS
491 hedge funds and large institutions have $13.5B invested in Ionis Pharmaceuticals in 2025 Q4 according to their latest regulatory filings, with 111 funds opening new positions, 166 increasing their positions, 142 reducing their positions, and 44 closing their positions.
152% more first-time investments, than exits
New positions opened: 111 | Existing positions closed: 44
50% more call options, than puts
Call options by funds: $153M | Put options by funds: $102M
22% more capital invested
Capital invested by funds: $11B → $13.5B (+$2.47B)
17% more repeat investments, than reductions
Existing positions increased: 166 | Existing positions reduced: 142
13% more funds holding
Funds holding: 435 → 491 (+56)
8% more funds holding in top 10
Funds holding in top 10: 12 → 13 (+1)
0.31% less ownership
Funds ownership: 105.5% → 105.2% (-0.31%)
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
Capital World Investors
Los Angeles,
California
|
+$394M |
| 2 |
JP Morgan Chase
New York
|
+$133M |
| 3 |
Franklin Resources
San Mateo,
California
|
+$99M |
| 4 |
BBA
Baker Bros. Advisors
New York
|
+$92.2M |
| 5 |
Two Sigma Investments
New York
|
+$81.5M |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
T. Rowe Price Investment Management
Baltimore,
Maryland
|
-$305M |
| 2 |
DTC
Deep Track Capital
Greenwich,
Connecticut
|
-$159M |
| 3 |
BG
Bellevue Group
Kuesnacht,
Switzerland
|
-$109M |
| 4 |
Adage Capital Partners
Boston,
Massachusetts
|
-$88.5M |
| 5 |
Macquarie Group
Sydney, NSW 2000,
Australia
|
-$74.1M |
IONS Hedge Fund Activity: Q4 2025 in Review
491 of the 8,224 institutional investors tracked by Wall St. Rank reported a position in Ionis Pharmaceuticals (IONS) for Q4 2025, worth a combined $13.5B — up 22% from $11B a quarter earlier.
Buyers outnumbered sellers: 111 funds opened new IONS positions and 44 closed out — a net gain of 67 holders — while 166 added to existing stakes and 142 trimmed.
The largest buyer was Capital World Investors, adding an estimated $394M. The largest seller was T. Rowe Price Investment Management, cutting an estimated $305M.
- 491 institutional investors held Ionis Pharmaceuticals (IONS) as of Q4 2025, up from 435 in Q3 2025.
- Funds reported $13.5B of Ionis Pharmaceuticals stock for Q4 2025, up 22% quarter-over-quarter.
- 111 funds opened new Ionis Pharmaceuticals positions in Q4 2025 and 44 closed out, a net change of +67 holders.
- The largest Ionis Pharmaceuticals buyer in Q4 2025 was Capital World Investors, an estimated $394M added.
- The largest Ionis Pharmaceuticals seller in Q4 2025 was T. Rowe Price Investment Management, an estimated $305M sold.
Based on aggregated 13F filings for Q4 2025.