Who owns Insmed (INSM)
Which tracked institutional funds hold INSM, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See INSM company fundamentals →
Ownership as of the 2026-Q1 13F filings (latest filed 2026-05-18). 13F is disclosed up to 45 days after quarter-end, so the most recent quarter fills in over the following weeks.
How the tape is positioned
173 tracked funds added or opened INSM while 221 trimmed or exited it between 2025-Q4 and 2026-Q1 — the tape is split. When large holders disagree on a name, the funds moving first are sometimes ahead of the story.
A prompt to read the filings, not a verdict. 13F is a quarter-end snapshot disclosed up to 45 days late; a fund adds or exits for mandate, benchmark, and timing reasons that have nothing to do with a view on the stock. This is a starting question, not a signal to trade.
Conviction spread
INSM’s largest tracked holder by dollar value, JPMORGAN CHASE & CO, sizes it at 0.3% of its own reported 13F book, while the median holder sizes it at 0.1% of theirs — a 0.2pp conviction gap — its largest holder concentrates the name more heavily than the typical one.
Book-share is each fund’s reported value in INSM divided by its whole reported 13F book, so it is comparable across funds of different sizes and is unaffected by stock splits. A higher share means a fund has committed more of its book to the name — a starting question about conviction, not a verdict or a signal to trade.
Institutional & insider positioning
Between 2025-Q4 and 2026-Q1, across 668 tracked filers holding INSM, 384 increased or opened the position and 322 reduced or closed it; over the same quarter, open-market insider Form 4 buying and selling roughly offset.
This fuses two public signals for the same quarter — how tracked institutions changed their positions and whether insiders bought or sold in the open market. It describes what was filed; it is a starting question, not a verdict or a signal to trade.
New buyers & exits
Funds opening or closing a position in INSM between the 2025-Q4 and 2026-Q1 13F filings, and the largest changes among funds holding it in both. New buyers and exits are counted on fund presence (split-invariant); adds and trims are measured on reported value.
New buyers 45
- VANGUARD PORTFOLIO MANAGEMENT LLC$1.7B
- VANGUARD CAPITAL MANAGEMENT LLC$1.6B
- Capital World Investors$223M
- VANGUARD FIDUCIARY TRUST CO$221M
- Paradigm Biocapital Advisors LP$205M
- VANGUARD ASSET MANAGEMENT, Ltd$59M
Full exits 51
- VANGUARD GROUP INC$3.7B
- Holocene Advisors, LP$139M
- TWO SIGMA ADVISERS, LP$69M
- Zurich Insurance Group Ltd/FI$49M
- Alberta Investment Management Corp$36M
- NOVO HOLDINGS A/S$35M
Largest adds
- FMR LLC$419M
- Invesco Ltd.$265M
- Artisan Partners Limited Partnership$224M
- WESTFIELD CAPITAL MANAGEMENT CO LP$165M
- D. E. Shaw & Co., Inc.$163M
- AMERIPRISE FINANCIAL INC$157M
Largest trims
- Darwin Global Management, Ltd.$1.1B
- BlackRock, Inc.$449M
- Orbis Allan Gray Ltd$421M
- NORGES BANK$374M
- JPMORGAN CHASE & CO$335M
- PRICE T ROWE ASSOCIATES INC /MD/$197M
Institutional holders
One row per tracked fund, largest reported value first. “% of value” is the fund’s share of this security’s tracked institutional value — not of shares outstanding. Rows marked stale are from an earlier filing than the security’s latest quarter — that fund is absent from the newest snapshot (position exited, or reported under a different name).
| Fund | Shares | Reported value | % of value | Quarter |
|---|---|---|---|---|
| JPMORGAN CHASE & CO added | 24,150,499 | $3.7B | 10.7% | 2026-Q1 |
| Darwin Global Management, Ltd. trimmed | 16,805,184 | $2.6B | 7.4% | 2026-Q1 |
| FMR LLC added | 16,143,583 | $1.7B | 5.0% | 2026-Q2 |
| VANGUARD PORTFOLIO MANAGEMENT LLC new | 10,371,802 | $1.7B | 4.9% | 2026-Q1 |
| BlackRock, Inc. added | 15,807,984 | $1.7B | 4.9% | 2026-Q2 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 9,642,131 | $1.6B | 4.6% | 2026-Q1 |
| BAKER BROS. ADVISORS LP added | 7,421,111 | $1.2B | 3.5% | 2026-Q1 |
| Artisan Partners Limited Partnership added | 6,527,301 | $1.1B | 3.1% | 2026-Q1 |
| Capital International Investors added | 8,238,124 | $878M | 2.5% | 2026-Q2 |
| RTW INVESTMENTS, LP added | 4,842,880 | $792M | 2.3% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 4,450,389 | $733M | 2.1% | 2026-Q1 |
| STATE STREET CORP added | 6,052,174 | $645M | 1.9% | 2026-Q2 |
| D. E. Shaw & Co., Inc. added | 5,877,959 | $627M | 1.8% | 2026-Q2 |
| AMERIPRISE FINANCIAL INC added | 3,057,718 | $500M | 1.4% | 2026-Q1 |
| FRANKLIN RESOURCES INC trimmed | 2,617,251 | $428M | 1.2% | 2026-Q1 |
| PRICE T ROWE ASSOCIATES INC /MD/ added | 3,405,290 | $363M | 1.0% | 2026-Q2 |
| NORGES BANK added | 3,377,641 | $360M | 1.0% | 2026-Q2 |
| Orbis Allan Gray Ltd trimmed | 1,872,824 | $306M | 0.9% | 2026-Q1 |
| UBS Group AG trimmed | 1,737,481 | $284M | 0.8% | 2026-Q1 |
| CITADEL ADVISORS LLC added | 2,556,973 | $273M | 0.8% | 2026-Q2 |
| BANK OF AMERICA CORP /DE/ trimmed | 1,502,281 | $246M | 0.7% | 2026-Q1 |
| Integral Health Asset Management, LLC added | 1,500,000 | $245M | 0.7% | 2026-Q1 |
| WESTFIELD CAPITAL MANAGEMENT CO LP added | 1,468,459 | $240M | 0.7% | 2026-Q1 |
| MAVERICK CAPITAL LTD added | 2,150,762 | $229M | 0.7% | 2026-Q2 |
| SEI INVESTMENTS CO added | 1,395,794 | $228M | 0.7% | 2026-Q1 |
| Capital World Investors new | 1,362,291 | $223M | 0.6% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 1,354,516 | $221M | 0.6% | 2026-Q1 |
| MILLENNIUM MANAGEMENT LLC added | 2,048,005 | $218M | 0.6% | 2026-Q2 |
| MORGAN STANLEY trimmed | 1,331,542 | $218M | 0.6% | 2026-Q1 |
| NORTHERN TRUST CORP added | 1,294,000 | $212M | 0.6% | 2026-Q1 |
| Castle Hook Partners LP added | 1,269,754 | $208M | 0.6% | 2026-Q1 |
| Bank of New York Mellon Corp trimmed | 1,262,749 | $206M | 0.6% | 2026-Q1 |
| Paradigm Biocapital Advisors LP added | 1,254,488 | $205M | 0.6% | 2026-Q1 |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC added | 1,215,025 | $199M | 0.6% | 2026-Q1 |
| NOMURA ASSET MANAGEMENT INTERNATIONAL INC. trimmed | 1,143,739 | $187M | 0.5% | 2026-Q1 |
| Pictet Asset Management Holding SA added | 1,102,248 | $179M | 0.5% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC added | 1,069,390 | $175M | 0.5% | 2026-Q1 |
| Fiera Capital Corp added | 1,021,970 | $167M | 0.5% | 2026-Q1 |
| NWI MANAGEMENT LP added | 1,014,000 | $166M | 0.5% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC trimmed | 942,646 | $154M | 0.4% | 2026-Q1 |
| Duquesne Family Office LLC added | 1,424,690 | $152M | 0.4% | 2026-Q2 |
| AMERICAN CENTURY COMPANIES INC added | 925,799 | $151M | 0.4% | 2026-Q1 |
| PRINCIPAL FINANCIAL GROUP INC added | 916,464 | $150M | 0.4% | 2026-Q1 |
| WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC trimmed | 902,666 | $148M | 0.4% | 2026-Q1 |
| ADAGE CAPITAL PARTNERS GP, L.L.C. added | 900,000 | $147M | 0.4% | 2026-Q1 |
| BALYASNY ASSET MANAGEMENT L.P. added | 1,326,430 | $141M | 0.4% | 2026-Q2 |
| FIL Ltd trimmed | 828,947 | $136M | 0.4% | 2026-Q1 |
| TWO SIGMA INVESTMENTS, LP added | 1,242,222 | $132M | 0.4% | 2026-Q2 |
| Amundi trimmed | 804,977 | $132M | 0.4% | 2026-Q1 |
| Legal & General Group Plc added | 787,079 | $129M | 0.4% | 2026-Q1 |
| RAYMOND JAMES FINANCIAL INC trimmed | 775,148 | $121M | 0.4% | 2026-Q1 |
| ALLIANCEBERNSTEIN L.P. added | 688,734 | $120M | 0.3% | 2026-Q1 |
| Hood River Capital Management LLC added | 688,554 | $113M | 0.3% | 2026-Q1 |
| SUMMIT PARTNERS PUBLIC ASSET MANAGEMENT, LLC trimmed | 653,445 | $107M | 0.3% | 2026-Q1 |
| Clearbridge Investments, LLC trimmed | 643,435 | $105M | 0.3% | 2026-Q1 |
| Artia Global Partners LP trimmed | 628,712 | $103M | 0.3% | 2026-Q1 |
| Swiss National Bank added | 625,912 | $102M | 0.3% | 2026-Q1 |
| GW&K Investment Management, LLC added | 623,048 | $102M | 0.3% | 2026-Q1 |
| JENNISON ASSOCIATES LLC added | 604,694 | $99M | 0.3% | 2026-Q1 |
| BNP PARIBAS FINANCIAL MARKETS trimmed | 604,600 | $99M | 0.3% | 2026-Q1 |
| WELLS FARGO & COMPANY/MN added | 597,384 | $98M | 0.3% | 2026-Q1 |
| TimesSquare Capital Management, LLC added | 584,798 | $96M | 0.3% | 2026-Q1 |
| DEUTSCHE BANK AG\ trimmed | 562,474 | $92M | 0.3% | 2026-Q1 |
| EVENTIDE ASSET MANAGEMENT, LLC added | 546,310 | $89M | 0.3% | 2026-Q1 |
| FEDERATED HERMES, INC. trimmed | 538,257 | $88M | 0.3% | 2026-Q1 |
| Nuveen, LLC trimmed | 534,750 | $87M | 0.3% | 2026-Q1 |
| ROYAL BANK OF CANADA added | 523,101 | $86M | 0.2% | 2026-Q1 |
| Sumitomo Mitsui Trust Group, Inc. added | 501,282 | $82M | 0.2% | 2026-Q1 |
| Ensign Peak Advisors, Inc added | 499,756 | $82M | 0.2% | 2026-Q1 |
| Affinity Asset Advisors, LLC added | 480,000 | $78M | 0.2% | 2026-Q1 |
| FRONTIER CAPITAL MANAGEMENT CO LLC added | 469,561 | $77M | 0.2% | 2026-Q1 |
| BNP PARIBAS ASSET MANAGEMENT Holding S.A. added | 467,753 | $76M | 0.2% | 2026-Q1 |
| JANUS HENDERSON GROUP PLC trimmed | 419,304 | $69M | 0.2% | 2026-Q1 |
| SAMLYN CAPITAL, LLC added | 417,205 | $68M | 0.2% | 2026-Q1 |
| Palo Alto Investors LP trimmed | 415,269 | $68M | 0.2% | 2026-Q1 |
| Candriam S.C.A. added | 401,735 | $66M | 0.2% | 2026-Q1 |
| DIMENSIONAL FUND ADVISORS LP added | 400,900 | $65M | 0.2% | 2026-Q1 |
| AQR CAPITAL MANAGEMENT LLC trimmed | 612,832 | $65M | 0.2% | 2026-Q2 |
| LORD, ABBETT & CO. LLC trimmed | 397,261 | $65M | 0.2% | 2026-Q1 |
| VICTORY CAPITAL MANAGEMENT INC trimmed | 396,245 | $65M | 0.2% | 2026-Q1 |
| Polar Capital Holdings Plc added | 368,107 | $60M | 0.2% | 2026-Q1 |
| GATEWAY INVESTMENT ADVISERS LLC | 365,000 | $60M | 0.2% | 2026-Q1 |
| VANGUARD ASSET MANAGEMENT, Ltd new | 360,075 | $59M | 0.2% | 2026-Q1 |
| WELLINGTON MANAGEMENT GROUP LLP added | 543,893 | $58M | 0.2% | 2026-Q2 |
| Point72 Asset Management, L.P. added | 536,997 | $57M | 0.2% | 2026-Q2 |
| Sofinnova Investments, Inc. added | 346,075 | $57M | 0.2% | 2026-Q1 |
| California Public Employees Retirement System trimmed | 344,612 | $56M | 0.2% | 2026-Q1 |
| MARSHALL WACE, LLP added | 501,930 | $54M | 0.2% | 2026-Q2 |
| Rock Springs Capital Management LP trimmed | 314,300 | $51M | 0.1% | 2026-Q1 |
| National Pension Service added | 311,881 | $51M | 0.1% | 2026-Q1 |
| CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM trimmed | 303,182 | $50M | 0.1% | 2026-Q1 |
| Nearwater Capital Markets, Ltd trimmed | 300,000 | $49M | 0.1% | 2026-Q1 |
| VANGUARD GROUP INC added | 21,076,344 | $3.7B | 10.6% | 2025-Q4 stale |
| Deep Track Capital, LP added | 1,750,000 | $176M | 0.5% | 2025-Q2 stale |
| Holocene Advisors, LP trimmed | 801,165 | $139M | 0.4% | 2025-Q4 stale |
| PERCEPTIVE ADVISORS LLC added | 702,130 | $101M | 0.3% | 2025-Q3 stale |
| Vestal Point Capital, LP added | 1,075,000 | $82M | 0.2% | 2025-Q1 stale |
| ALKEON CAPITAL MANAGEMENT LLC | 500,000 | $72M | 0.2% | 2025-Q3 stale |
| TWO SIGMA ADVISERS, LP added | 395,000 | $69M | 0.2% | 2025-Q4 stale |
| DEERFIELD MANAGEMENT COMPANY, L.P. trimmed | 471,000 | $68M | 0.2% | 2025-Q3 stale |
Ownership over time
Tracked institutional holder count and total shares held by filing quarter (independent scales). The curated-era tail and any mid-ingest latest quarter are handled honestly — a partial quarter is not drawn as a collapse.
Reading this table
Funds hold the same stock for different reasons — an index fund “holds” almost everything, an active manager sizes a name to a mandate and a benchmark, and each fund entered at its own price and time. Because 13F is filed up to 45 days after quarter-end, every row is a backward-looking snapshot; a manager may have traded since. Share-class siblings (a company’s A and C shares) are rolled up to one line so a dual-class name is never double-counted. Compare like-for-like. A large holder is not an endorsement, and a fund exiting is not a warning — this is a starting question, not a verdict.
About 13F filings
A Form 13F is a quarterly disclosure that institutional investment managers with over $100 million in US-listed equities must file with the SEC. In plain English: it is a snapshot of the long stock positions a fund held at the end of a quarter. It covers long US-listed equities only — not short positions, options, cash, or private holdings — and the funds shown are the large sample we track, not the complete 13F universe.