Alnylam Pharmaceuticals, Inc.
Alnylam Pharmaceuticals, Inc. (ALNY) Stock Ownership
Institutional vs insider vs public ownership from 13F and float data — top holders, activity, and insider trades below.
SEC 13F · FMP · ALNY · as of Sep 30, 2025
Ownership Breakdown
869
Institutional Holders
▲ 174 vs Q2
$59.21B
Total Inst. Value
▲ $16.12B vs Q2
133.51M
Shares Outstanding
freeFloat 99.57%
133.88M
13F Shares Held
▲ 234,794 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
ALNY largest shareholders · institutional ownership
Q3 2025 · SEC 13F
Showing top 10 holders
| Holder | Shares | % Owned | Weight | Value | Reported | Change |
|---|---|---|---|---|---|---|
FMR LLC pharmaceutical preparations | 16.77M | 12.93% | 12.93% | $7.65T | Nov 13, 2025 | ▲ 961.1K |
CAPITAL WORLD INVESTORS pharmaceutical preparations | 16.43M | 12.67% | 12.67% | $7.49T | Nov 13, 2025 | ▼ 370.8K |
VANGUARD GROUP INC pharmaceutical preparations | 13.57M | 10.46% | 10.46% | $6.19T | Nov 7, 2025 | ▲ 268.3K |
BLACKROCK, INC. pharmaceutical preparations | 9.90M | 7.64% | 7.64% | $4.52T | Nov 12, 2025 | ▼ 76.6K |
CAPITAL RESEARCH GLOBAL INVESTORS pharmaceutical preparations | 7.22M | 5.57% | 5.57% | $3.29T | Nov 13, 2025 | ▲ 31.2K |
JPMORGAN CHASE & CO pharmaceutical preparations | 4.54M | 3.50% | 3.50% | $2.07T | Nov 26, 2025 | ▲ 2.48M |
GROUPAMA ASSET MANAGMENT pharmaceutical preparations | 4.03M | 3.11% | 3.11% | $18.61B | Dec 1, 2025 | ▲ 2.48M |
STATE STREET CORP pharmaceutical preparations | 3.08M | 2.38% | 2.38% | $1.41T | Nov 14, 2025 | ▼ 91.6K |
BAILLIE GIFFORD & CO pharmaceutical preparations | 2.79M | 2.15% | 2.15% | $1.27T | Oct 31, 2025 | ▼ 242.5K |
GEODE CAPITAL MANAGEMENT, LLC pharmaceutical preparations | 2.50M | 1.93% | 1.93% | $1.14T | Nov 12, 2025 | ▲ 100.5K |
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
29
Increased
+13.94M shares0
New Positions
first time holders21
Decreased
−9.65M shares0
Sold Out
fully exitedNet shares change (top 50)
+4.29M
+13.94M / −9.65M
Net new holders
+8
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
ALNY 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.
19
Buy transactions
15
Sell transactions
1.27
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 |
|---|---|---|---|---|---|---|---|
PYOTT DAVID E I director | Jun 1, 2026 | Sale | 921 | $297.71 | $274.2K | 4.5K | Form 4 ↗ |
PYOTT DAVID E I director | Jun 1, 2026 | Sale | 1,175 | $298.91 | $351.2K | 3.3K | Form 4 ↗ |
PYOTT DAVID E I director | Jun 1, 2026 | Sale | 1,222 | $299.87 | $366.4K | 2.1K | Form 4 ↗ |
PYOTT DAVID E I director | Jun 1, 2026 | Sale | 495 | $300.72 | $148.9K | 1.6K | Form 4 ↗ |
PYOTT DAVID E I director | Jun 1, 2026 | Sale | 17 | $302.65 | $5.1K | 1.6K | Form 4 ↗ |
Cravatt Benjamin director | Jun 1, 2026 | Award | 4,393 | $295.63 | $1.30M | 4.4K | Form 4 ↗ |
Sigal Charles Elliott director | May 20, 2026 | Award | 671 | — | — | 1.4K | Form 4 ↗ |
Sigal Charles Elliott director | May 20, 2026 | Award | 1,441 | $298.48 | $430.1K | 1.4K | Form 4 ↗ |
SCHULMAN AMY W director | May 20, 2026 | Award | 838 | — | — | 24.0K | Form 4 ↗ |
SCHULMAN AMY W director | May 20, 2026 | Award | 1,802 | $298.48 | $537.9K | 1.8K | 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
Alnylam Pharmaceuticals, Inc. (ALNY) is primarily owned by institutional investors, who hold approximately 100.0% of total shares outstanding. Company insiders own approximately 0.43%, while retail and public investors account for the remaining 0.00%.
The largest institutional shareholder of Alnylam Pharmaceuticals, Inc. is FMR LLC, holding approximately 16.77 million shares — equal to 12.93% of outstanding shares — as of September 30, 2025.
A total of 869 institutional investors currently hold ALNY stock, with a combined institutional value of approximately $59.21 billion as of the most recent 13F filing period.
Frequently asked questions
ALNY ownershipAlnylam Pharmaceuticals, Inc. (ALNY) is primarily owned by institutional investors, who hold approximately 100.0% of shares. The largest shareholder is FMR LLC with a 12.93% stake. Company insiders hold 0.43%. Data sourced from SEC Form 13F as of September 30, 2025.