Ranked by reported Q1 2026 13F market value
Share of total reported institutional value in ALNY held by the largest 10 / 25 filers.
| # | Institution | Shares Held | Market Value | QoQ Change | Ownership % | % of Fund |
|---|---|---|---|---|---|---|
| 1 | FMR LLC | 14.6M | $4.82B | -8.3% | 10.927% | 0.26% |
| 2 | Capital World Investors | 10.8M | $3.57B | -33.7% | 8.096% | 0.49% |
| 3 | BlackRock, Inc. | 10.4M | $3.46B | +0.4% | 7.828% | 0.06% |
| 4 | Capital Research Global Investors | 9.5M | $3.13B | +39.7% | 7.098% | 0.49% |
| 5 | VANGUARD PORTFOLIO MANAGEMENT LLC | 6.5M | $2.15B | — | 4.865% | 0.11% |
| 6 | VANGUARD CAPITAL MANAGEMENT LLC | 5.9M | $1.97B | — | 4.457% | 0.05% |
| 7 | STATE STREET CORP | 3.3M | $1.10B | +2.9% | 2.490% | 0.04% |
| 8 | GEODE CAPITAL MANAGEMENT, LLC | 2.7M | $884.6M | +0.4% | 1.994% | 0.06% |
| 9 | BAILLIE GIFFORD & CO | 2.5M | $825.1M | -4.1% | 1.869% | 0.84% |
| 10 | TWO SIGMA INVESTMENTS, LP | 2.0M | $659.3M | +223.4% | 1.493% | 0.53% |
| 11 | WELLINGTON MANAGEMENT GROUP LLP | 1.9M | $640.5M | +18.9% | 1.451% | 0.12% |
| 12 | DODGE & COX | 1.9M | $638.3M | -1.8% | 1.446% | 0.35% |
| 13 | AMERICAN CENTURY COMPANIES INC | 1.8M | $596.3M | +21.4% | 1.351% | 0.31% |
| 14 | D. E. Shaw & Co., Inc. | 1.5M | $487.8M | +74.8% | 1.105% | 0.46% |
| 15 | Clearbridge Investments, LLC | 1.4M | $448.7M | +127.1% | 1.016% | 0.39% |
| 16 | Orbis Allan Gray Ltd | 1.3M | $441.7M | -17.5% | 1.000% | 1.86% |
| 17 | Invesco Ltd. | 1.3M | $427.4M | -40.4% | 0.968% | 0.07% |
| 18 | MARSHALL WACE, LLP | 1.1M | $363.7M | +99.9% | 0.824% | 0.40% |
| 19 | MORGAN STANLEY | 1.0M | $331.8M | +3.4% | 0.751% | 0.02% |
| 20 | BANK OF AMERICA CORP /DE/ | 967K | $319.9M | +41.1% | 0.725% | 0.02% |
| 21 | Legal & General Group Plc | 935K | $309.3M | -2.8% | 0.701% | 0.07% |
| 22 | AQR CAPITAL MANAGEMENT LLC | 913K | $297.9M | -0.8% | 0.684% | 0.14% |
| 23 | NORTHERN TRUST CORP | 858K | $283.9M | +0.0% | 0.643% | 0.04% |
| 24 | VANGUARD FIDUCIARY TRUST CO | 841K | $278.2M | — | 0.630% | 0.07% |
| 25 | Qube Research & Technologies Ltd | 838K | $277.3M | +8.2% | 0.628% | 0.33% |
denotes a marquee investor (Buffett, Burry, ARK, Tiger Global, Pershing Square, Baupost and other widely-followed managers). “% of Fund” shows how much of that investor’s total 13F portfolio is invested in ALNY — a direct measure of their conviction.
Filings activity in ALNY during Q1 2026, grouped by how each filer changed its position.
8 quarters of 13F filings · Δ columns show change vs prior quarter
| Quarter | Inst. Holders | Δ Holders | Ownership % | Δ Ownership | Total 13F Value | Δ Value |
|---|---|---|---|---|---|---|
| Q1 2026 | 765 | 7.0% | 100.89% | 31.62 pp | $38.08B | 24% |
| Q4 2025 | 823 | +3.9% | 132.51% | 19.60 pp | $50.01B | 13% |
| Q3 2025 | 792 | +23% | 152.11% | +45.04 pp | $57.41B | +42% |
| Q2 2025 | 643 | +7.3% | 107.07% | +23.18 pp | $40.41B | +28% |
| Q1 2025 | 599 | +5.3% | 83.89% | +9.94 pp | $31.66B | +13% |
| Q4 2024 | 569 | +5.6% | 73.95% | 9.46 pp | $27.91B | 11% |
| Q3 2024 | 539 | +8.0% | 83.41% | 3.66 pp | $31.48B | 4.2% |
| Q2 2024 | 499 | — | 87.07% | — | $32.86B | — |
Source: SEC 13F institutional filings. Ownership % requires market cap data and will show once linked. Δ columns compare to the immediately prior filed quarter.
Quick answers to the most common questions about buying ALNY stock.
Based on Q1 2026 13F filings, institutional ownership of Alnylam Pharmaceuticals, Inc. stands at 100.9%, held across 765 reporting institutions.
FMR LLC is the largest reported institutional holder of ALNY, with approximately 14,579,166 shares worth $4.82B as of Q1 2026.
Yes — 1 widely-followed marquee investor appear among the top 25 institutional holders of ALNY, including TWO SIGMA INVESTMENTS, LP.
Our composite Smart Money Score for ALNY is 28 out of 100 (Bearish). It combines net institutional buying activity, ownership shift, marquee investor presence, and holder-count growth.
113 institutions opened new positions in ALNY during Q1 2026, while 171 fully exited. 158 added to existing positions and 490 trimmed.
ALNY institutional ownership fell by 31.62 percentage points quarter-over-quarter, with a net change of -58 holders.
The top 10 institutions account for 59.3% of all reported 13F value in ALNY, and the top 25 account for 75.4%.
All data is sourced from SEC Form 13F filings, which institutional investment managers with at least $100M in assets are required to file each quarter. We process every 13F filing from EDGAR and recompute the aggregates after each cycle. Insider transactions are sourced from Form 4 filings.
Alnylam Pharmaceuticals, Inc. (ALNY) Institutional Ownership