Ionis Pharmaceuticals
IONS
436 hedge funds and large institutions have $11B invested in Ionis Pharmaceuticals in 2025 Q3 according to their latest regulatory filings, with 114 funds opening new positions, 136 increasing their positions, 116 reducing their positions, and 37 closing their positions.
208% more first-time investments, than exits
New positions opened: 114 | Existing positions closed: 37
128% more call options, than puts
Call options by funds: $170M | Put options by funds: $74.8M
65% more capital invested
Capital invested by funds: $6.67B → $11B (+$4.34B)
20% more funds holding
Funds holding: 362 → 436 (+74)
17% more repeat investments, than reductions
Existing positions increased: 136 | Existing positions reduced: 116
0% more funds holding in top 10
Funds holding in top 10: 12 → 12 (0)
0.59% less ownership
Funds ownership: 106.09% → 105.5% (-0.59%)
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
DM
Deerfield Management
New York
|
+$96.7M |
| 2 |
Marshall Wace
London,
United Kingdom
|
+$46.2M |
| 3 |
Citadel Advisors
Miami,
Florida
|
+$44.3M |
| 4 |
American Century Companies
Kansas City,
Missouri
|
+$43.9M |
| 5 |
Pictet Asset Management
Carouge,
Switzerland
|
+$38.3M |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
T. Rowe Price Investment Management
Baltimore,
Maryland
|
-$141M |
| 2 |
Adage Capital Partners
Boston,
Massachusetts
|
-$121M |
| 3 |
Millennium Management
New York
|
-$91.3M |
| 4 |
BG
Bellevue Group
Kuesnacht,
Switzerland
|
-$78.5M |
| 5 |
BI
BVF Inc
San Francisco,
California
|
-$75.6M |
IONS Hedge Fund Activity: Q3 2025 in Review
436 of the 7,640 institutional investors tracked by Wall St. Rank reported a position in Ionis Pharmaceuticals (IONS) for Q3 2025, worth a combined $11B — up 65% from $6.67B a quarter earlier.
Buyers outnumbered sellers: 114 funds opened new IONS positions and 37 closed out — a net gain of 77 holders — while 136 added to existing stakes and 116 trimmed.
The largest buyer was Deerfield Management, opening a new position worth an estimated $96.7M. The largest seller was T. Rowe Price Investment Management, cutting an estimated $141M.
- 436 institutional investors held Ionis Pharmaceuticals (IONS) as of Q3 2025, up from 362 in Q2 2025.
- Funds reported $11B of Ionis Pharmaceuticals stock for Q3 2025, up 65% quarter-over-quarter.
- 114 funds opened new Ionis Pharmaceuticals positions in Q3 2025 and 37 closed out, a net change of +77 holders.
- The largest Ionis Pharmaceuticals buyer in Q3 2025 was Deerfield Management, an estimated $96.7M added.
- The largest Ionis Pharmaceuticals seller in Q3 2025 was T. Rowe Price Investment Management, an estimated $141M sold.
Based on aggregated 13F filings for Q3 2025.