BAKER BROS. ADVISORS LP: INSMED INC (INSM): Quarterly 13F Position History
As of Q1 2026, BAKER BROS. ADVISORS LP reported 7,421,111 shares of INSMED INC (INSM), worth $1.2B and representing 7.0% of its 13F equity book. Quarter-over-quarter share count change: + 828,365 (+12.6%) . The position first appeared in Q1 2016 and has been disclosed across 41 13F-HR filings in Pactolio's tracked window.
- 7,421,111Shares Held (Latest Filing)
- $1.2BReported Market Value (Latest Filing)
- 7.0%Portfolio Weight (% of 13F Equity Book)
- +828,365Quarter-over-Quarter Share Change
- +$66.1MQuarter-over-Quarter Value Change
- 7,712,900Peak Reported Shares (Historical)
Quarterly 13F-HR Disclosure History Source: SEC 13F-HR filings, 41 quarter s
| Quarter | Shares | QoQ Share Change | Share Change (%) | Market Value | Weight | Implied Price |
|---|---|---|---|---|---|---|
| Q1 2026 | 7,421,111 | +828,365 | +12.6% | $1.2B | 7.0% | $163.5 |
| Q4 2025 | 6,592,746 | 110,738 | -1.7% | $1.1B | 6.7% | $174.0 |
| Q3 2025 | 6,703,484 | 1,009,416 | -13.1% | $965.4M | 7.0% | $144.0 |
| Q2 2025 | 7,712,900 | +2,332,274 | +43.3% | $776.2M | 7.5% | $100.6 |
| Q1 2025 | 5,380,626 | +373,763 | +7.5% | $410.5M | 4.5% | $76.3 |
| Q4 2024 | 5,006,863 | +590,945 | +13.4% | $345.7M | 3.7% | $69.0 |
| Q3 2024 | 4,415,918 | +839,880 | +23.5% | $322.4M | 3.3% | $73.0 |
| Q2 2024 | 3,576,038 | +3,233,038 | +942.6% | $239.6M | 3.1% | $67.0 |
| Q1 2024 | 343,000 | 0 | — | $9.3M | 0.1% | $27.1 |
| Q4 2023 | 343,000 | 0 | — | $10.6M | 0.1% | $31.0 |
| Q3 2023 | 343,000 | 0 | — | $8.7M | 0.0% | $25.3 |
| Q2 2023 | 343,000 | 0 | — | $7.2M | 0.0% | $21.1 |
| Q1 2023 | 343,000 | +323,050 | +1619.3% | $5.8M | 0.0% | $17.1 |
| Q4 2022 | 19,950 | 0 | — | $398.6K | 0.0% | $20.0 |
| Q3 2022 | 19,950 | 2,136,051 | -99.1% | $430.0K | 0.0% | $21.6 |
| Q2 2022 | 2,156,001 | 0 | — | $42.5M | 0.2% | $19.7 |
| Q1 2022 | 2,156,001 | 0 | — | $50.7M | 0.3% | $23.5 |
| Q4 2021 | 2,156,001 | 0 | — | $58.7M | 0.3% | $27.2 |
| Q3 2021 | 2,156,001 | 0 | — | $59.4M | 0.3% | $27.5 |
| Q2 2021 | 2,156,001 | 0 | — | $61.4M | 0.3% | $28.5 |
| Q1 2021 | 2,156,001 | 0 | — | $73.4M | 0.3% | $34.1 |
| Q4 2020 | 2,156,001 | 116,711 | -5.1% | $71.8M | 0.3% | $33.3 |
| Q3 2020 | 2,272,712 | 752,672 | -24.9% | $73.0M | 0.3% | $32.1 |
| Q2 2020 | 3,025,384 | 0 | — | $83.3M | 0.4% | $27.5 |
| Q1 2020 | 3,025,384 | +580,119 | +23.7% | $48.5M | 0.3% | $16.0 |
| Q4 2019 | 2,445,265 | +215,505 | +9.7% | $58.4M | 0.3% | $23.9 |
| Q3 2019 | 2,229,760 | 232,456 | -9.4% | $39.3M | 0.3% | $17.6 |
| Q2 2019 | 2,462,216 | +384,615 | +18.5% | $63.0M | 0.4% | $25.6 |
| Q1 2019 | 2,077,601 | +225,619 | +12.2% | $60.4M | 0.4% | $29.1 |
| Q4 2018 | 1,851,982 | 0 | — | $24.3M | 0.2% | $13.1 |
| Q3 2018 | 1,851,982 | +1,151,982 | +164.6% | $37.4M | 0.2% | $20.2 |
| Q2 2018 | 700,000 | 0 | — | $16.6M | 0.1% | $23.6 |
| Q1 2018 | 700,000 | 0 | — | $15.8M | 0.1% | $22.5 |
| Q4 2017 | 700,000 | 0 | — | $21.8M | 0.2% | $31.2 |
| Q3 2017 | 700,000 | +300,000 | +75.0% | $21.8M | 0.2% | $31.2 |
| Q2 2017 | 400,000 | 0 | — | $6.9M | 0.1% | $17.2 |
| Q1 2017 | 400,000 | 0 | — | $7.0M | 0.1% | $17.5 |
| Q4 2016 | 400,000 | 0 | — | $5.3M | 0.1% | $13.2 |
| Q3 2016 | 400,000 | 1,100,000 | -73.3% | $5.8M | 0.1% | $14.5 |
| Q2 2016 | 1,500,000 | 0 | — | $14.8M | 0.2% | $9.9 |
| Q1 2016 | 1,500,000 | — | — | $19.0M | 0.2% | $12.7 |
Methodology & FAQ
How This Position History Is Sourced
Each row is one SEC Form 13F-HR filing disclosing this position. Share count, market value, and reported quarter are taken verbatim from the filing; portfolio weight is recomputed against the same filing's total reported equity book. Implied price-per-share is market value divided by shares — a quarter-end mark, not the manager's cost basis. See the full methodology document for the normalization rules.
When did BAKER BROS. ADVISORS LP first disclose a INSM position in 13F-HR filings?
BAKER BROS. ADVISORS LP first reported INSMED INC (INSM) on its 13F-HR filing for the period ending 2016-03-31 (Q1 2016). The position has appeared on 41 reported quarters within Pactolio's tracked window.
What was BAKER BROS. ADVISORS LP's most recent quarter-over-quarter share-count change in INSM?
Between Q4 2025 and Q1 2026, BAKER BROS. ADVISORS LP added 828,365 shares of INSM (+12.6%), bringing the total reported position to 7,421,111 shares at a market value of $1.2B.
Does the implied price-per-share represent BAKER BROS. ADVISORS LP's cost basis in INSM?
No. The implied price-per-share column is the 13F-HR reported market value divided by reported share count on the filing date (end of quarter). It is a quarter-end mark, not a cost basis or transaction price. Use it as a sanity check on the value column, not as an indicator of the manager's entry or exit price.