Insmed
INSM · NASDAQ
Who owns INSM
Largest institutional holders, from their latest 13F filings
The 10 largest institutions hold 41.1% of INSM’s shares.
- Fidelity Management & Research Company LLC6.3%
- BlackRock Institutional Trust Company, N.A.5.3%
- Vanguard Portfolio Management, LLC4.8%
- Vanguard Capital Management, LLC4.5%
- Next 6 largest institutions20.2%
- All other shareholders58.9%
| Holder | Shares | % of shares |
|---|---|---|
| Fidelity Management & Research Company LLC | 13.56M | 6.26% |
| BlackRock Institutional Trust Company, N.A. | 11.48M | 5.29% |
| Vanguard Portfolio Management, LLC | 10.41M | 4.80% |
| Vanguard Capital Management, LLC | 9.79M | 4.52% |
| Baker Bros. Advisors LP | 8.80M | 4.06% |
| JP Morgan Asset Management | 8.28M | 3.82% |
| Capital International Investors | 8.24M | 3.80% |
| Darwin Global Management Ltd | 6.43M | 2.97% |
| Orbis Investment Management Ltd. | 6.08M | 2.80% |
| State Street Investment Management (US) | 6.05M | 2.79% |
Largest mutual fund holders
| Holder | Shares | % of shares |
|---|---|---|
| Vanguard Total Stock Market Index Fund | 6.91M | 3.19% |
| American Funds Growth Fund of America | 6.25M | 2.89% |
| Statens Pensjonsfond Utland | 3.58M | 1.65% |
| Vanguard Extended Market Index Fund | 2.50M | 1.15% |
| Vanguard Small-Cap Index Fund | 2.49M | 1.15% |
Insider trades
Form 4 filings by officers, directors and large holders
Over the last 6 months, insiders sold $59.82M (44 trades) of INSM on the open market, with no buys.
| Insider | Type | Shares | Value |
|---|---|---|---|
| Brennan David R | Sale | 25.00K | $3.10M |
| SHAROKY MELVIN MD | Sale | 5.00K | $637.65K |
| Adsett Roger | Option exercise | 80.97K | — |
| Adsett Roger | Option exercise | 76.60K | — |
| Adsett Roger | Option exercise | 82.28K | — |
| Adsett Roger | Sale | 239.85K | $31.96M |
| Adsett Roger | Option exercise | 80.97K | $2.47M |
| Adsett Roger | Option exercise | 76.60K | $1.31M |
| Adsett Roger | Option exercise | 82.28K | $1.12M |
| Flammer Martina M.D. | Option exercise | 8.89K | — |
Congressional trades
Disclosed by members of Congress over the last 12 months
| Member | Type | Amount | Traded |
|---|---|---|---|
| Josh GottheimerHouse | Sale | $1K–$15K | Jun 10, 2026 |
Short interest
Settled Sep 30, 2026
- Shares short
- 13.80M
- Days to cover
- 6.50
- % of shares outstanding
- 6.37%
- Average daily volume
- 2.12M
- Change since last report
- +27.8%
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