- Quarter end
- 31 Dec 2025
- the date the book describes
- Filed
- 27 Oct 2026
- latest of these filings; the earliest 10 Feb 2026
- Managers listing it
- 29
- at least, of 95 tracked, among listed positions
- Comparable managers
- 92
- filed both Q3 2025 and Q4 2025; 15 listed it in both
- Shares listed
- 39,381,388
- combined, among listed positions
- Reported value
- $6.9bn
- combined, at the quarter end
Among the 92 comparable managers: 14 buyers (opened or added shares) and 20 sellers (trimmed or exited), at least, among listed positions. Their net change in shares was -3,132,924.
Managers listing INSM in Q4 2025
29 of 29 holders
Largest increases and reductions, by shares
Increases
- Invesco Ltdexisting position · 7,518,338 shares now+5,514,467
- Fidelity (FMR LLC)existing position · 9,927,936 shares now+746,973
- Two Sigma Advisers LPexisting position · 395,000 shares now+343,700
- Balyasny Asset Management LLCexisting position · 380,561 shares now+343,080
- Two Sigma Investments LPexisting position · 962,156 shares now+189,376
Reductions
- T. Rowe Price Associates Incexisting position · 4,039,466 shares now-2,892,000
- D. E. Shaw & Co.existing position · 4,350,995 shares now-1,306,469
- Millennium Management LLCexisting position · 1,311,654 shares now-1,024,458
- Citadel Advisors LLCexisting position · 1,157,295 shares now-900,346
- Jane Street Group LLCexisting position · 13,505 shares now-778,229
New positions and exits
New (3)
Exited (6)
- Maverick Capital Ltdwas $95m
- Voloridge Investment Management LLCwas $68m
- Point72 Asset Management LPwas $67m
- Brevan Howard Capital Management LPwas $42m
- Schonfeld Strategic Advisors LLCwas $8.7m
- Tudor Investment Corpwas $245k
Ownership over time
Tracked managers listing it, at least.
| Quarter | Holders | Reported value | Buyers | Sellers |
|---|---|---|---|---|
| Q3 2013 | 1 | $20m | n.a. | n.a. |
| Q4 2013 | 1 | $28m | n.a. | n.a. |
| Q1 2014 | 2 | $39m | n.a. | n.a. |
| Q2 2014 | 2 | $43m | n.a. | n.a. |
| Q3 2014 | 1 | $34m | n.a. | n.a. |
| Q4 2014 | 1 | $44m | n.a. | n.a. |
| Q1 2015 | 1 | $174m | n.a. | n.a. |
| Q2 2015 | 1 | $211m | n.a. | n.a. |
| Q3 2015 | 1 | $168m | n.a. | n.a. |
| Q4 2015 | 2 | $169m | n.a. | n.a. |
| Q3 2016 | 1 | $146m | n.a. | n.a. |
| Q1 2017 | 1 | $189m | n.a. | n.a. |
| Q2 2017 | 4 | $180m | n.a. | n.a. |
| Q3 2017 | 7 | $890m | n.a. | n.a. |
| Q4 2017 | 4 | $954m | n.a. | n.a. |
| Q1 2018 | 3 | $428m | n.a. | n.a. |
| Q2 2018 | 3 | $475m | n.a. | n.a. |
| Q3 2018 | 4 | $416m | n.a. | n.a. |
| Q4 2018 | 1 | $150m | n.a. | n.a. |
| Q1 2019 | 4 | $897m | n.a. | n.a. |
| Q2 2019 | 6 | $559m | n.a. | n.a. |
| Q3 2019 | 6 | $284m | n.a. | n.a. |
| Q4 2019 | 6 | $680m | n.a. | n.a. |
| Q1 2020 | 7 | $472m | n.a. | n.a. |
| Q2 2020 | 7 | $1.0bn | n.a. | n.a. |
| Q3 2020 | 9 | $1.2bn | n.a. | n.a. |
| Q4 2020 | 8 | $1.0bn | n.a. | n.a. |
| Q1 2021 | 6 | $816m | n.a. | n.a. |
| Q2 2021 | 6 | $800m | n.a. | n.a. |
| Q3 2021 | 7 | $803m | n.a. | n.a. |
| Q4 2021 | 7 | $760m | n.a. | n.a. |
| Q1 2022 | 8 | $680m | n.a. | n.a. |
| Q2 2022 | 7 | $566m | n.a. | n.a. |
| Q3 2022 | 10 | $379m | n.a. | n.a. |
| Q4 2022 | 8 | $360m | n.a. | n.a. |
| Q1 2023 | 6 | $282m | n.a. | n.a. |
| Q2 2023 | 6 | $353m | n.a. | n.a. |
| Q3 2023 | 7 | $415m | n.a. | n.a. |
| Q4 2023 | 8 | $539m | 4 | 5 |
| Q1 2024 | 8 | $437m | 7 | 3 |
| Q2 2024 | 16 | $2.2bn | 10 | 6 |
| Q3 2024 | 18 | $2.3bn | 10 | 10 |
| Q4 2024 | 14 | $1.6bn | 4 | 8 |
| Q1 2025 | 14 | $1.9bn | 9 | 4 |
| Q2 2025 | 23 | $3.7bn | 17 | 6 |
| Q3 2025 | 20 | $5.8bn | 10 | 9 |
| Q4 2025 | 19 | $6.6bn | 14 | 20 |
| Q1 2026 | 19 | $7.0bn | 16 | 17 |
| Q2 2026 | 21 | $5.0bn | 28 | 11 |
Compare with…
Holders over time, buyers and sellers, and the managers holding both, side by side for up to four stocks.
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How much of the picture this is
A 13F is a manager’s long US-listed equity book at a quarter end, filed up to 45 days later. It shows no shorts, cash, bonds or performance, and it is never today’s portfolio. Large books are listed to their largest positions, so a manager missing from this table may still hold a small position below that line. These are 95 tracked managers, not the institutional market.
Which funds own INSM, latest filings →Back to the 13F Explorer →