Alnylam Pharmaceuticals Inc
Ownership
Ownership Structure
Who owns Alnylam Pharmaceuticals Inc (ALNY)? This page shows the largest institutions and funds, the ownership structure and the latest insider transactions. 99.6% of the shares are freely tradable; institutional investors hold 102.1%.
Largest Shareholders
Institutions
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| FMR Inc | 11.23 | 15,023,962 | +3.1 | 06/30/2026 |
| Capital World Investors | 8.33 | 11,144,846 | +3.2 | 06/30/2026 |
| BlackRock Inc | 8.15 | 10,907,675 | +4.4 | 06/30/2026 |
| Capital Research Global Investors | 7.29 | 9,750,699 | +3.0 | 06/30/2026 |
| Vanguard Portfolio Management, LLC | 4.89 | 6,538,390 | +0.7 | 06/30/2026 |
| Vanguard Capital Management, LLC | 4.51 | 6,029,478 | +1.4 | 06/30/2026 |
| T. Rowe Price Investment Management,Inc. | 4.22 | 5,642,173 | +8.6 | 06/30/2026 |
Funds
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| American Funds Growth Fd of Amer A | 6.70 | 8,960,487 | +17.6 | 09/30/2026 |
| American Funds AMCAP A | 3.38 | 4,526,680 | +10.4 | 09/30/2026 |
| T. Rowe Price Capital Appreciation | 3.37 | 4,510,570 | -0.7 | 09/30/2026 |
Largest reported positions according to regulatory filings; stake as a percentage of shares outstanding, change versus the previous filing. Source: fundamentals data.
Insider holdings
| Person | Role | Shares | Value | As of | Type |
|---|---|---|---|---|---|
| Greenstreet Yvonne | Chief Executive Officer | 95,802 | 15,807,330 $ | Sep 19, 2026 | direct |
| Supran Bryan | EVP, CLO and Secretary | 12,807 | 2,113,155 $ | Oct 2, 2026 | direct |
Holdings as of each person's most recent SEC Form 4 filing — excluding options and RSUs, which are not shares yet. Holdings may have changed between two filings.
Insiders
Insider Transactions
| Date | Person | Role | Type | Shares | Price | Value |
|---|---|---|---|---|---|---|
| Oct 2, 2026 | Supran Bryan | EVP, CLO and Secretary | Sell | 1,758 | 226.88 | 398,855 |
| Sep 19, 2026 | Greenstreet Yvonne | Chief Executive Officer | Other | 107 | 0.00 | – |
Reportable transactions by officers and major shareholders from SEC Form 4 filings. "Other" includes things like stock grants and option exercises without a buy/sell character. View all insider transactions →
Data as of: October 30, 2026 · Source: fundamental data & SEC filings (annual and quarterly reports, 10-K/10-Q)
Note: pure fact-based analysis, not investment advice and not a solicitation to buy or sell. All figures without guarantee.