Alnylam Pharmaceuticals, Inc. (ALNY) Ownership
ALNY ownership summary
as of October 18, 2026- Institutions
- 101.7% of shares outstanding
- Insiders
- 0.18% of shares outstanding
- Shares outstanding
- 133.8M
- Float
- 133.2M shares available to trade
- Short interest
- 7.68% 7.7M shares short
- Days to cover
- 5.17 short interest up 7.2% vs prior month
- Institutions 101.69%
- Insiders 0.18%
ALNY top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | FMR Inc | 11.23% | 15.0M | $3.48B | +444,796 (+3.1%) | June 30, 2026 |
| 2 | Capital World Investors | 8.33% | 11.1M | $2.58B | +342,498 (+3.2%) | June 30, 2026 |
| 3 | BlackRock Inc | 8.15% | 10.9M | $2.53B | +462,767 (+4.4%) | June 30, 2026 |
| 4 | Capital Research Global Investors | 7.29% | 9.8M | $2.26B | +279,518 (+3.0%) | June 30, 2026 |
| 5 | Vanguard Portfolio Management, LLC | 4.89% | 6.5M | $1.52B | +47,110 (+0.7%) | June 30, 2026 |
| 6 | Vanguard Capital Management, LLC | 4.51% | 6.0M | $1.40B | +82,772 (+1.4%) | June 30, 2026 |
| 7 | T. Rowe Price Investment Management,Inc. | 4.22% | 5.6M | $1.31B | +448,849 (+8.6%) | June 30, 2026 |
| 8 | Amvescap Plc. | 2.81% | 3.8M | $870.4M | −320,802 (−7.9%) | June 30, 2026 |
| 9 | State Street Corp | 2.66% | 3.6M | $824.3M | +232,991 (+7.0%) | June 30, 2026 |
| 10 | JPMorgan Chase & Co | 2.00% | 2.7M | $620.3M | −3.6M (−57.7%) | June 30, 2026 |
| 11 | Geode Capital Management, LLC | 1.97% | 2.6M | $611.1M | −24,545 (−0.9%) | June 30, 2026 |
| 12 | Baillie Gifford & Co Limited. | 1.82% | 2.4M | $565.6M | −53,977 (−2.2%) | June 30, 2026 |
| 13 | NORGES BANK | 1.70% | 2.3M | $526.7M | +19,038 (+0.8%) | June 30, 2026 |
| 14 | Wellington Management Company LLP | 1.58% | 2.1M | $489.3M | +174,482 (+9.0%) | June 30, 2026 |
| 15 | Orbis Allan Gray Ltd | 1.49% | 2.0M | $460.7M | +652,582 (+48.9%) | June 30, 2026 |
| 16 | Dodge & Cox | 1.46% | 2.0M | $453.3M | +26,140 (+1.4%) | June 30, 2026 |
| 17 | Two Sigma Investments LLC | 1.40% | 1.9M | $434.9M | −116,640 (−5.9%) | June 30, 2026 |
| 18 | American Century Companies Inc | 1.39% | 1.9M | $429.8M | +51,593 (+2.9%) | June 30, 2026 |
| 19 | ClearBridge Advisors, LLC | 0.94% | 1.3M | $292.0M | −96,553 (−7.1%) | June 30, 2026 |
| 20 | T. Rowe Price Associates, Inc. | 0.86% | 1.1M | $266.4M | −283,547 (−19.8%) | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 13 holders added 3.3M shares and 7 cut 4.5M.
ALNY top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | American Funds Growth Fd of Amer A | 5.70% | 7.6M | $1.77B | −403,937 (−5.0%) | June 30, 2026 |
| 2 | T. Rowe Price Capital Appreciation | 3.40% | 4.5M | $1.05B | +393,240 (+9.5%) | August 31, 2026 |
| 3 | Vanguard MStar Total Stk Mkt Idx Invest | 3.17% | 4.2M | $983.9M | −8,320 (−0.2%) | August 31, 2026 |
| 4 | American Funds AMCAP A | 3.07% | 4.1M | $950.9M | +357,021 (+9.5%) | June 30, 2026 |
| 5 | Vanguard MStar Mid Cap Index Instl | 2.16% | 2.9M | $669.5M | −1,552 (−0.1%) | August 31, 2026 |
| 6 | Invesco QQQ Trust | 2.09% | 2.8M | $647.8M | −4,554 (−0.2%) | September 30, 2026 |
| 7 | Fidelity OTC | 1.57% | 2.1M | $487.1M | −39,900 (−1.9%) | August 31, 2026 |
| 8 | Vanguard Health Care Inv | 1.32% | 1.8M | $408.4M | +149,888 (+9.3%) | June 30, 2026 |
| 9 | American Funds Invmt Co of Amer A | 1.21% | 1.6M | $373.9M | −334,845 (−17.2%) | June 30, 2026 |
| 10 | Vanguard MStar Growth Index Investor | 1.20% | 1.6M | $373.2M | −2,745 (−0.2%) | August 31, 2026 |
| 11 | T. Rowe Price Mid-Cap Growth | 0.96% | 1.3M | $298.2M | +50,443 (+4.1%) | August 31, 2026 |
| 12 | Dodge & Cox Stock I | 0.92% | 1.2M | $285.9M | — | June 30, 2026 |
| 13 | American Funds IS® Growth 1 | 0.90% | 1.2M | $277.7M | −78,610 (−6.2%) | June 30, 2026 |
| 14 | iShares Biotechnology ETF | 0.78% | 1.0M | $241.2M | −7,880 (−0.8%) | September 30, 2026 |
| 15 | Vanguard MStar Mid Cap Growth ETF | 0.77% | 1.0M | $237.8M | +4,681 (+0.5%) | August 31, 2026 |
| 16 | American Funds New Perspective A | 0.76% | 1.0M | $236.5M | — | June 30, 2026 |
| 17 | Fidelity Growth Company Fund | 0.67% | 894K | $207.3M | −398,000 (−30.8%) | August 31, 2026 |
| 18 | Strategic Advisers Fidelity US TtlStk | 0.66% | 888K | $206.0M | +4,700 (+0.5%) | August 31, 2026 |
| 19 | T. Rowe Price Capital Apprec Eq ETF | 0.60% | 801K | $185.8M | +960 (+0.1%) | September 30, 2026 |
| 20 | American Funds American Balanced A | 0.60% | 800K | $185.5M | +800,000 (0.0%) | June 30, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
ALNY insider transactions
latest 20| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2026-04-06 | Melissa Mclaughlin | Sell | $330.42 | 2,286 | $755,340 |
| 2026-04-02 | Melissa Mclaughlin | Sell | $319.59 | 1,624 | $519,014 |
| 2026-03-03 | Kevin Joseph Fitzgerald | Sell | $319.73 | 1,652 | $528,194 |
| 2026-03-03 | Pushkal Garg | Sell | $319.74 | 1,775 | $567,538 |
| 2026-03-02 | Jeffrey V Poulton | Sell | $327.65 | 2,206 | $722,796 |
| 2026-03-02 | Kevin Joseph Fitzgerald | Sell | $327.65 | 1,598 | $523,585 |
| 2026-03-02 | Pushkal Garg | Sell | $327.66 | 1,717 | $562,592 |
| 2026-03-02 | Tolga Tanguler | Sell | $327.65 | 1,598 | $523,585 |
| 2026-03-02 | Yvonne Greenstreet | Sell | $327.65 | 6,799 | $2.2M |
| 2026-02-17 | Kevin Joseph Fitzgerald | Sell | $331.96 | 2,041 | $677,530 |
| 2026-02-13 | Jeffrey V Poulton | Sell | $310.08 | 2,242 | $695,199 |
| 2026-02-13 | Kevin Joseph Fitzgerald | Sell | $310.08 | 1,959 | $607,447 |
| 2026-02-13 | Pushkal Garg | Sell | $310.08 | 2,242 | $695,199 |
| 2026-02-13 | Tolga Tanguler | Sell | $310.08 | 1,959 | $607,447 |
| 2026-02-13 | Yvonne Greenstreet | Sell | $310.08 | 6,958 | $2.2M |
| 2026-01-13 | Kevin Joseph Fitzgerald | Sell | $370.33 | 2,290 | $848,056 |
| 2026-01-12 | Yvonne Greenstreet | Sell | $362.86 | 9,577 | $3.5M |
| 2026-01-12 | Tolga Tanguler | Sell | $362.87 | 1,510 | $547,934 |
| 2026-01-12 | Kevin Joseph Fitzgerald | Sell | $362.87 | 1,510 | $547,934 |
| 2026-01-12 | Jeffrey V Poulton | Sell | $362.87 | 2,780 | $1.0M |
Reported trades by company officers, directors and other filers (including disclosures by members of Congress where EODHD lists them). "—" where the filing gives no share count.
ALNY shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns ALNY
Institutional investors own 101.7% of Alnylam's shares and insiders 0.18%. The largest holder is FMR Inc with 11.23% of the shares (15.0M), as of June 30, 2026. Among the top 20 institutions, 13 added shares and 7 reduced their stake in the latest filings. Short interest is 7.68% of the float, or 5.17 days of average trading volume. The share count rose 77.1% since 2014.
Related: ALNY analyst forecast, ALNY key metrics. See the ALNY stock overview for the latest quote and news.
ALNY ownership FAQ
Who owns the most Alnylam stock?
The largest shareholders of Alnylam are FMR Inc (11.23%), Capital World Investors (8.33%), BlackRock Inc (8.15%), Capital Research Global Investors (7.29%), Vanguard Portfolio Management, LLC (4.89%).
What percentage of Alnylam is owned by institutions?
Institutions hold 101.7% of Alnylam's shares outstanding; insiders hold 0.18%.
Which funds own Alnylam?
The largest fund holders of Alnylam are American Funds Growth Fd of Amer A (5.70%), T. Rowe Price Capital Appreciation (3.40%), Vanguard MStar Total Stk Mkt Idx Invest (3.17%), American Funds AMCAP A (3.07%), Vanguard MStar Mid Cap Index Instl (2.16%).
What is Alnylam's short interest?
7.7M shares of Alnylam were sold short, 7.68% of the float; at the average daily volume it would take 5.17 days to cover.
Are insiders buying or selling Alnylam?
Of the latest 20 reported insider transactions in Alnylam (since January 12, 2026), 0 were purchases and 20 were sales.
How many shares of Alnylam are outstanding?
Alnylam has 133.8M shares outstanding, of which 133.2M are in the public float.