Alnylam Pharmaceuticals, Inc. (ALNY) Institutional Ownership

Institutions by Trading Activity

Ownership Statistics

134,655,365Shares Outstanding

465,607Shares held by institutions

$154,865,544Value of institutional holdings

92.77%Institutional ownership %

1.50%Shares Changed QoQ

796No. of institutional investors

Shares Owned by Institutions

Shares Purchased/Sold by Institutions

Ownership Summary

The institutional landscape for Alnylam Pharmaceuticals, Inc. (NASDAQ:ALNY) includes 796 filers as of the latest reporting cycle ending December 2025.

The percentage of Alnylam Pharmaceuticals owned by institutions changed from 98.3% in September 2025 to 92.8% in December 2025, marking a slight down trend.
On a quarter-over-quarter basis, institutional holdings shifted by 1.50%, with a year-over-year an increase of 35.37% in the count of filers.
Of these 796 institutional investors, 432 increased their holdings in Alnylam Pharmaceuticals, while 271 of them reduced positions, and 93 investors maintained their exposure.
The aggregate institutional position in Alnylam Pharmaceuticals now stands at 124.92Mn shares as of December 2025, after investors increased their holdings (up by 1.85Mn shares quarter on quarter which is down 4.51Mn shares year over year).
The top institutional stake in Alnylam Pharmaceuticals as of December 31, 2025 belongs to Capital World Investors, which owns 16.30Mn shares, or 12.11% of the company.
Among the most significant buyers of Alnylam Pharmaceuticals during December 2025 were NORGES BANK (2.25Mn), BlackRock, Inc. (497.27K), UBS Group AG (357.13K), Rockefeller Capital Management L.P. (355.97K), NOMURA ASSET MANAGEMENT INTERNATIONAL INC. (311.76K).
Leading sellers of Alnylam Pharmaceuticals stock in December 2025 included T. Rowe Price Investment Management, Inc. (1.02Mn), FMR LLC (865.48K), BANK OF AMERICA CORP /DE/ (813.31K), JANE STREET GROUP, LLC (660.86K), MACQUARIE GROUP LTD (623.06K).
The top 10 institutional holders of Alnylam Pharmaceuticals for the quarter ending December 2025 included Capital World Investors (16.30Mn), FMR LLC (15.90Mn), VANGUARD GROUP INC (13.55Mn), BlackRock, Inc. (10.40Mn), Capital Research Global Investors (6.78Mn), JPMORGAN CHASE & CO (4.72Mn), STATE STREET CORP (3.23Mn), GEODE CAPITAL MANAGEMENT, LLC (2.65Mn), BAILLIE GIFFORD & CO (2.60Mn), NORGES BANK (2.25Mn).

796 Institutional Holders

465,607 Total Shares Held

Rows:

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Owner Name	Date	Shares Held	Change (QoQ)	Change (%)	Value (USD)
Capital World Investors	31 Dec, 2025	16,301,772	-132,481	-0.81%	$6,482,389,029.00
FMR LLC	31 Dec, 2025	15,902,149	-865,476	-5.16%	$6,323,489,463.00
VANGUARD GROUP INC	31 Dec, 2025	13,553,932	-11,520	-0.08%	$5,389,721,059.00
BlackRock, Inc.	31 Dec, 2025	10,400,874	497,273	5.02%	$4,135,907,609.00
Capital Research Global Investors	31 Dec, 2025	6,779,708	-443,132	-6.14%	$2,695,945,984.00
JPMORGAN CHASE & CO	31 Dec, 2025	4,719,999	176,229	3.88%	$1,876,908,009.00
STATE STREET CORP	31 Dec, 2025	3,228,956	147,481	4.79%	$1,283,994,353.00
GEODE CAPITAL MANAGEMENT, LLC	31 Dec, 2025	2,650,722	151,480	6.06%	$1,056,883,596.00
BAILLIE GIFFORD & CO	31 Dec, 2025	2,600,979	-188,377	-6.75%	$1,034,279,300.00
NORGES BANK	31 Dec, 2025	2,252,775	2,252,775	0.00%	$895,815,979.00
DODGE & COX	31 Dec, 2025	1,964,415	-356,815	-15.37%	$781,149,625.00
WELLINGTON MANAGEMENT GROUP LLP	31 Dec, 2025	1,628,931	-197,390	-10.81%	$647,744,413.00
Orbis Allan Gray Ltd	31 Dec, 2025	1,618,219	-332,743	-17.06%	$643,484,786.00
AMERICAN CENTURY COMPANIES INC	31 Dec, 2025	1,485,161	-156,280	-9.52%	$590,576,553.00
T. Rowe Price Investment Management, Inc.	31 Dec, 2025	1,151,347	-1,022,637	-47.04%	$457,834.00
TWO SIGMA ADVISERS, LP	31 Dec, 2025	1,132,560	240,060	26.90%	$450,362,484.00
ARROWSTREET CAPITAL, LIMITED PARTNERSHIP	31 Dec, 2025	1,127,162	-228,447	-16.85%	$448,215,969.00
MORGAN STANLEY	31 Dec, 2025	970,157	244,096	33.62%	$385,784,277.00
Legal & General Group Plc	31 Dec, 2025	961,496	73,716	8.30%	$382,338,888.00
AQR CAPITAL MANAGEMENT LLC	31 Dec, 2025	919,946	175,938	23.65%	$365,816,460.00

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