Alnylam Pharmaceuticals

ALNY • NASDAQ

Alnylam Pharmaceuticals is a biotechnology company in the healthcare sector on NASDAQ, led by Yvonne L. Greenstreet, MBChB, MBA, with a market cap of $61.5B. As of Q3 2025, 99% of shares are held by 797 institutional investors, with FMR LLC as the largest holder at 12.79%.

Chief Executive OfficerYvonne L. Greenstreet, MBChB, MBA

Market Cap$61.5B

Biotechnology

Healthcare

Employees2.1K

Websitealnylam.com

Country

United States of America

Overview

Overview of institutional ownership in ALNY as of Q3 2025 with a market cap of $59.8B

All Institutions

Institutions: 797
Value Held: $58.9B
Shares Held: 129.3M
Avg Position: $74.0M
Median Position: $1.2M

Hedge Funds

Hedge Funds: 85
Value Held: $3.3B
Shares Held: 7.2M
Avg Position: $38.6M
Median Position: $5.8M

Ownership Breakdown

Institutional (non-HF)

93.12%

$55.7B

Hedge Funds

5.5%

$3.3B

Retail & Other

1.38%

$827.2M

Based on market cap of $59.8B as of Q3 2025. Institutional (non-HF) excludes hedge funds to avoid double counting.

Biggest Investors

Institutions with the largest positions in ALNY as of Q3 2025

Institution	Key People	Position Value	Ownership	Owned Since	Total AUM (Long)
FMR LLC Institution	-	$7.6B 0.40% of portfolio	12.79% 16.8M shares	≤ Q2 2013 Held for 12y 5m+	$1.92T
C Capital World Investors Institution	-	$7.5B 1.03% of portfolio	12.54% 16.4M shares	≤ Q2 2013 Held for 12y 5m+	$730.00B
VANGUARD GROUP INC Institution	Salim Ramji CEO	$6.2B 0.09% of portfolio	10.35% 13.6M shares	≤ Q2 2013 Held for 12y 5m+	$6.69T
B BlackRock, Inc. Institution	-	$4.5B 0.08% of portfolio	7.56% 9.9M shares	≤ Q2 2013 Held for 12y 5m+	$5.67T
Capital Research Global Investors RIA/Wealth	Sardar Sheraz Iftikhar CEO	$3.3B 0.62% of portfolio	5.51% 7.2M shares	Q4 2022 Held for 2y 11m	$532.36B
JPMORGAN CHASE & CO Institution	Jamie Dimon CEO	$2.1B 0.13% of portfolio	3.47% 4.5M shares	≤ Q2 2013 Held for 12y 5m+	$1.56T
STATE STREET CORP Institution	Ronald P. O'Hanley CEO	$1.4B 0.05% of portfolio	2.35% 3.1M shares	≤ Q2 2013 Held for 12y 5m+	$2.88T
B BAILLIE GIFFORD & CO Institution	-	$1.3B 0.94% of portfolio	2.13% 2.8M shares	≤ Q2 2013 Held for 12y 5m+	$134.80B
GEODE CAPITAL MANAGEMENT LLC ETF Provider	David Kenneth Lane CEO	$1.1B 0.07% of portfolio	1.91% 2.5M shares	≤ Q2 2013 Held for 12y 5m+	$1.57T
DODGE & COX Long Only Manager	Dana Morton Emery CEO	$1.1B 0.57% of portfolio	1.77% 2.3M shares	Q2 2016 Held for 9y 5m	$185.33B

Net Capital Flow

Institutional buying and selling activity for ALNY in Q3 2025

Net Flow: −$671.3M
Buyers: 306
Sellers: 262
Total Bought: +$6.3B
Total Sold: −$6.9B
Avg Position: $88.9M

Biggest Buyers

Institution	Net Bought	Current Position
JPMORGAN CHASE & CO Institution	+$1.1B +2.5M shares	$2.1B 4.5M shares
ARROWSTREET CAPITAL LIMITED PARTNERSHIP Hedge Fund•Quant	+$540.8M +1.2M shares	$618.2M 1.4M shares
FMR LLC Institution	+$438.3M +961.1K shares	$7.6B 16.8M shares
J JANE STREET GROUP, LLC Institution	+$426.8M +935.9K shares	$437.2M 958.8K shares
Q Qube Research & Technologies Ltd Institution	+$369.9M +811.3K shares	$369.9M 811.3K shares
TWO SIGMA ADVISERS, LLC Hedge Fund•Multi-Strategy	+$285.6M +626.4K shares	$407.0M 892.5K shares
AQR CAPITAL MANAGEMENT LLC Hedge Fund•Multi-Strategy	+$251.0M +555.8K shares	$336.0M 744.0K shares
MILLENNIUM MANAGEMENT LLC Hedge Fund•Multi-Strategy	+$209.5M +459.5K shares	$250.8M 549.9K shares
JACOBS LEVY EQUITY MANAGEMENT, INC Hedge Fund•Quant	+$179.1M +392.7K shares	$187.1M 410.3K shares
SUSQUEHANNA INTERNATIONAL GROUP, LLP Private Equity	+$168.4M +369.4K shares	$263.4M 577.6K shares

Biggest Sellers

Institution	Net Sold	Current Position
REGENERON PHARMACEUTICALS, INC. Institution	−$1.4B −3.1M shares	$634.9M 1.4M shares
T T. Rowe Price Investment Management, Inc. Insurance Manager	−$960.9M −2.1M shares	$991.3M 2.2M shares
PRICE T ROWE ASSOCIATES INC /MD/ Long Only Manager	−$613.2M −1.3M shares	$820.9M 1.8M shares
Winslow Capital Management, LLC Long Only Manager	−$536.3M −1.2M shares	$608.8K 1.3K shares
DODGE & COX Long Only Manager	−$399.4M −875.9K shares	$1.1B 2.3M shares
Holocene Advisors, LP Hedge Fund•Long/Short	−$266.2M −583.7K shares	$6.0M 13.1K shares
Woodline Partners LP Hedge Fund•Long/Short	−$242.3M −531.3K shares	$41.9M 91.8K shares
CITADEL ADVISORS LLC Hedge Fund•Multi-Strategy	−$173.0M −379.4K shares	$101.2M 221.8K shares
C Capital World Investors Institution	−$169.1M −370.8K shares	$7.5B 16.4M shares
UBS GLOBAL ASSET MANAGEMENT AMERICAS INC Long Only Manager	−$113.9M −249.8K shares	$323.1M 708.6K shares

Entry and Exit Activity

Institutions that initiated new positions or completely exited ALNY in Q3 2025

New Positions: 114
New Value: $268.3M
Exited Positions: 46
Exited Value: $199.8M

New Positions

Institution	Position Value
SUSQUEHANNA ADVISORS GROUP, INC. Private Equity	$130.5M 286.1K shares
CONGRESS ASSET MANAGEMENT CO /MA Long Only Manager	$54.2M 118.8K shares
Bronte Capital Management Pty Ltd. Hedge Fund•Long/Short	$17.8M 35.0K shares
Q Quantessence Capital LLC Hedge Fund•Quant	$7.2M 15.9K shares
LINDEN ADVISORS LP Hedge Fund•Multi-Strategy	$6.5M 14.4K shares
F Fieldview Capital Management, LLC Hedge Fund•Long/Short	$5.8M 12.7K shares
C CIBC World Markets Inc. Institution	$5.5M 12.1K shares
N NWK Group, Inc. RIA/Wealth	$3.9M 8.5K shares
WEST MICHIGAN ADVISORS, LLC RIA/Wealth	$2.5M 5.4K shares
W. E. Donoghue & Co., LLC Long Only Manager	$2.1M 4.6K shares

Exited Positions

Institution	Previous Position
T Tri Locum Partners LP Hedge Fund•Long/Short	$29.2M 89.5K shares
A ADAGE CAPITAL PARTNERS GP LLC Institution	$27.5M 84.4K shares
A AXA Institution	$26.9M 82.5K shares
Partner Fund Management, L.P. Hedge Fund•Sector	$23.6M 72.2K shares
Cercano Management LLC Family Office	$18.6M 57.0K shares
Ikarian Capital, LLC Hedge Fund•Event Driven	$18.5M 56.6K shares
Iron Triangle Partners LP Hedge Fund•Long/Short	$9.6M 29.3K shares
Cinctive Capital Management LP Hedge Fund•Multi-Strategy	$7.5M 22.9K shares
Symphony Financial, Ltd. Co. RIA/Wealth	$7.3M 22.5K shares
BOOTHBAY FUND MANAGEMENT, LLC Fund of Funds	$6.3M 19.2K shares

Options Activity

Institutions with the largest Call and Put options positions in ALNY as of Q3 2025

Call Positions: 24
Call Value: $534.8M
Put Positions: 29
Put Value: $621.7M

Call Positions

Institution	Position Value
SUSQUEHANNA INTERNATIONAL GROUP, LLP Private Equity	$365.3M 8.0K contracts
P PEAK6 LLC Institution	$23.6M 518.0 contracts
J JANE STREET GROUP, LLC Institution	$22.9M 502.0 contracts
CITADEL ADVISORS LLC Hedge Fund•Multi-Strategy	$22.1M 484.0 contracts
MILLENNIUM MANAGEMENT LLC Hedge Fund•Multi-Strategy	$16.2M 355.0 contracts
N NOMURA HOLDINGS INC Institution	$16.2M 355.0 contracts
D D. E. Shaw & Co., Inc. Institution	$14.5M 319.0 contracts
W WOLVERINE TRADING, LLC Institution	$13.1M 293.0 contracts
CITIGROUP INC Institution	$10.9M 240.0 contracts
WELLS FARGO & COMPANY/MN Institution	$9.1M 200.0 contracts

Put Positions

Institution	Position Value
SUSQUEHANNA INTERNATIONAL GROUP, LLP Private Equity	$152.3M 3.3K contracts
SUSQUEHANNA ADVISORS GROUP, INC. Private Equity	$125.8M 2.8K contracts
BANK OF AMERICA CORP /DE/ Institution	$91.2M 2.0K contracts
6 683 Capital Management, LLC Hedge Fund•Long/Short	$61.9M 1.4K contracts
FARALLON CAPITAL MANAGEMENT LLC Hedge Fund•Multi-Strategy	$45.6M 1.0K contracts
CITADEL ADVISORS LLC Hedge Fund•Multi-Strategy	$32.3M 708.0 contracts
J JANE STREET GROUP, LLC Institution	$17.7M 389.0 contracts
Caption Management, LLC Hedge Fund•Long/Short	$13.7M 300.0 contracts
CITIGROUP INC Institution	$13.7M 300.0 contracts
N NOMURA HOLDINGS INC Institution	$12.3M 270.0 contracts

Most Committed Institutions

Institutions with ALNY as the highest % of their portfolio as of Q3 2025

Institution	Key People	Portfolio Weight	Ownership	Owned Since	Total AUM (Long)
REGENERON PHARMACEUTICALS, INC. Institution	Leonard S. Schleifer, M.D., Ph.D. CEO	90.64% $634.9M	1.06% 1.4M shares	Q4 2024 Held for 11 months	$700.4M
SUSQUEHANNA ADVISORS GROUP, INC. Private Equity	-	5.12% $130.5M	0.22% 286.1K shares	Q3 2025 Held for 2 months	$2.5B
Parkman Healthcare Partners LLC Hedge Fund•Long/Short	Gregory Arthur Martinez CIO	4.39% $40.0M	0.07% 87.7K shares	Q3 2024 Held for 1y 2m	$910.1M
B Bellevue Group AG Institution	-	4.24% $203.6M	0.34% 446.5K shares	Q1 2016 Held for 9y 8m	$4.8B
O Orbis Allan Gray Ltd RIA/Wealth	Don Lynn Ray Managing Partner	3.82% $889.6M	1.49% 2.0M shares	Q2 2024 Held for 1y 5m	$23.3B
ROSENBLUM SILVERMAN SUTTON S F INC /CA RIA/Wealth	Philip Anthony Huff President	3.53% $15.5M	0.03% 34.0K shares	Q1 2020 Held for 5y 8m	$438.7M
ORBIMED ADVISORS LLC Hedge Fund•Sector	Sam Block Iii CFO	3.34% $137.5M	0.23% 301.6K shares	Q4 2023 Held for 1y 11m	$4.1B
DIADEMA PARTNERS LP Hedge Fund•Long/Short	Timothy Beau Bassett CIO	3.18% $4.6M	0.01% 10.0K shares	Q1 2025 Held for 8 months	$143.3M
E Eagle Health Investments LP Hedge Fund•Long/Short	Gary Johnathan Stern Founder	2.84% $10.8M	0.02% 23.7K shares	Q4 2020 Held for 4y 11m	$380.9M
A Artia Global Partners LP Hedge Fund•Long/Short	Onusa Nmn Chantanapongwanij Managing Partner	2.77% $15.8M	0.03% 34.6K shares	Q2 2024 Held for 1y 5m	$568.3M

Hedge Fund Spotlight

Discover hedge funds investing in ALNY

CAPSTONE INVESTMENT ADVISORS, LLC

Hedge Fund • Multi-Strategy

Portfolio ManagerPaul Matthew Britton

Portfolio Value: $9.4B
Positions: 1,012
Last Reported: Q3 2025

Sector Allocation

Position in Alnylam Pharmaceuticals

Market Value: $561.3K
Shares Held: 1.2K
Portfolio Weight: 0.01%
Owned Since: 2025-Q3

Top Holding	Sector	Market Value	Weight
1 Nvidia NVDA	Semiconductors Technology	$1.3B	13.35%
2 Microsoft MSFT	Software - Infrastructure Technology	$1.1B	11.84%
3 Amazon AMZN	Specialty Retail Consumer Cyclical	$1.0B	11.12%