Insmed Incorporated
Insmed Incorporated (INSM) Stock Ownership
Institutional vs insider vs public ownership from 13F and float data — top holders, activity, and insider trades below.
SEC 13F · FMP · INSM · as of Sep 30, 2025
Ownership Breakdown
624
Institutional Holders
▲ 61 vs Q2
$30.33B
Total Inst. Value
▲ $9.18B vs Q2
216.75M
Shares Outstanding
freeFloat 91.48%
210.88M
13F Shares Held
▲ 490,062 vs Q2
Institutional ownership = 13F shares ÷ total outstanding. Insider % = 100 − free float. Public % = free float − institution %. Data: FMP /symbol-positions-summary + /shares-float + SEC EDGAR.
Top Institutional Holders
INSM largest shareholders · institutional ownership
Q3 2025 · SEC 13F
Showing top 10 holders
| Holder | Shares | % Owned | Weight | Value | Reported | Change |
|---|---|---|---|---|---|---|
JPMORGAN CHASE & CO pharmaceutical preparations | 23.05M | 12.18% | 12.18% | $3.32T | Nov 26, 2025 | ▲ 7.41M |
DARWIN GLOBAL MANAGEMENT, LTD. pharmaceutical preparations | 20.46M | 9.66% | 9.66% | $2.90T | Nov 14, 2025 | ▲ 1.11M |
VANGUARD GROUP INC pharmaceutical preparations | 19.94M | 9.41% | 9.41% | $2.87T | Nov 7, 2025 | ▲ 2.29M |
BLACKROCK, INC. pharmaceutical preparations | 12.36M | 5.84% | 5.84% | $1.78T | Nov 12, 2025 | ▲ 1.22M |
FMR LLC pharmaceutical preparations | 9.18M | 4.34% | 4.34% | $1.32T | Nov 13, 2025 | ▲ 4.09M |
CAPITAL INTERNATIONAL INVESTORS pharmaceutical preparations | 7.55M | 3.57% | 3.57% | $1.09T | Nov 13, 2025 | ▲ 75.0K |
PRICE T ROWE ASSOCIATES INC /MD/ pharmaceutical preparations | 6.93M | 3.27% | 3.27% | $998.20B | Nov 14, 2025 | ▼ 4.30M |
BAKER BROS. ADVISORS LP pharmaceutical preparations | 6.70M | 3.17% | 3.17% | $965.37B | Nov 14, 2025 | ▼ 1.01M |
D. E. SHAW & CO., INC. pharmaceutical preparations | 5.66M | 2.67% | 2.67% | $814.73B | Nov 14, 2025 | ▲ 2.23M |
ARTISAN PARTNERS LIMITED PARTNERSHIP pharmaceutical preparations | 4.94M | 2.33% | 2.33% | $711.08B | Nov 12, 2025 | ▲ 1.62M |
Data from SEC Form 13F filings. Ownership bar normalised to largest holder. Change flags: isNew / isSoldOut / changeInSharesNumber (FMP extract-analytics/holder).
Institutional Activity
Q3 2025 vs prior quarter
Q3 2025
24
Increased
+27.52M shares0
New Positions
first time holders24
Decreased
−14.40M shares0
Sold Out
fully exitedNet shares change (top 50)
+13.12M
+27.52M / −14.40M
Net new holders
+0
0 new / 0 exited
Based on top 50 institutional holders by position size. Fields: isNew, isSoldOut, changeInSharesNumber (FMP extract-analytics/holder, limit=50).
Insider Buying vs Selling
INSM insider trading · insider activity
Source: SEC Form 4
Insiders have been primarily selling shares recently. Selling may be driven by pre-scheduled Rule 10b5-1 plans rather than negative sentiment.
16
Buy transactions
45
Sell transactions
0.36
Buy/Sell ratio
$0M
Total disposed
Recent Insider Transactions
Showing 10 most recent · Common Stock only
| Name · Role | Date | Type | Shares | Price | Value | After Trans. | Filing |
|---|---|---|---|---|---|---|---|
Adsett Roger Chief Operating Officer | Jun 3, 2026 | Sale | 2,370 | $102.27 | $242.4K | 98.6K | Form 4 ↗ |
Bonstein Sara Chief Financial Officer | Jun 3, 2026 | Sale | 2,404 | $102.27 | $245.9K | 69.1K | Form 4 ↗ |
Smith Michael Alexander Chief Legal Officer | Jun 3, 2026 | Sale | 2,159 | $102.27 | $220.8K | 39.5K | Form 4 ↗ |
Lewis William Chair and CEO | Jun 3, 2026 | Sale | 7,605 | $102.27 | $777.8K | 265.4K | Form 4 ↗ |
Flammer Martina M.D. Chief Medical Officer | Jun 3, 2026 | Sale | 2,566 | $102.27 | $262.4K | 62.3K | Form 4 ↗ |
Flammer Martina M.D. Chief Medical Officer | Jun 5, 2026 | Sale | 1,858 | $103.78 | $192.8K | 60.5K | Form 4 ↗ |
Smith Michael Alexander Chief Legal Officer | May 22, 2026 | Sale | 6,149 | $108.47 | $667.0K | 41.6K | Form 4 ↗ |
Lewis William Chair and CEO | May 18, 2026 | Sale | 5,753 | $105.32 | $605.9K | 292.8K | Form 4 ↗ |
Lewis William Chair and CEO | May 18, 2026 | Sale | 11,836 | $106.39 | $1.26M | 281.0K | Form 4 ↗ |
Lewis William Chair and CEO | May 18, 2026 | Sale | 7,975 | $106.97 | $853.1K | 273.0K | Form 4 ↗ |
Source: /insider-trading/search (FMP stable). Buy/Sell direction: acquisitionOrDisposition A=Buy, D=Sell. RSU vesting (M-Exempt) excluded from sentiment bar. All data from SEC EDGAR public filings.
About institutional & insider ownership
Insmed Incorporated (INSM) is primarily owned by institutional investors, who hold approximately 97.3% of total shares outstanding. Company insiders own approximately 8.52%, while retail and public investors account for the remaining 0.00%.
The largest institutional shareholder of Insmed Incorporated is JPMORGAN CHASE & CO, holding approximately 23.05 million shares — equal to 12.18% of outstanding shares — as of September 30, 2025.
A total of 624 institutional investors currently hold INSM stock, with a combined institutional value of approximately $30.33 billion as of the most recent 13F filing period.
Frequently asked questions
INSM ownershipInsmed Incorporated (INSM) is primarily owned by institutional investors, who hold approximately 97.3% of shares. The largest shareholder is JPMORGAN CHASE & CO with a 12.18% stake. Company insiders hold 8.52%. Data sourced from SEC Form 13F as of September 30, 2025.