AI Holders Summary · Q2 2026

1,091 institutions reported BIIB in Q2 2026. BlackRock, Inc. leads at 19.4% of the visible book.

Top holders

Sorted by position value. Source: SEC EDGAR 13F-HR filings.

Hide index funds / market makers / custodians(5 on this page)

#HolderValueShares% port.Quarter

BlackRock, Inc.

CIK 0002012383

$3.5B16.0M0.05%Q2 2026 02

PRIMECAP MANAGEMENT CO/CA/

CIK 0000763212

$2.7B14.8M2.13%Q1 2026 03

FMR LLC

CIK 0000315066

$2.3B12.8M0.12%Q1 2026 04

VANGUARD CAPITAL MANAGEMENT LLC

CIK 0002100119· Index

$1.7B9.5M0.04%Q1 2026 05

STATE STREET CORP

CIK 0000093751

$1.6B7.3M0.05%Q2 2026 06

Vanguard Portfolio Management

CIK 0002100121· Index

$1.2B6.5M0.06%Q1 2026 07

GEODE CAPITAL MANAGEMENT, LLC

CIK 0001214717· Index

$793M4.3M0.05%Q1 2026 08

WELLINGTON MANAGEMENT GROUP LLP

CIK 0000902219

$543M3.0M0.10%Q1 2026 09

MORGAN STANLEY

CIK 0000895421

$398M2.2M0.02%Q1 2026 10

JPMORGAN CHASE & CO

CIK 0000019617

$378M2.0M0.02%Q1 2026 11

AQR CAPITAL MANAGEMENT LLC

CIK 0001167557

$346M1.9M0.16%Q1 2026 12

Invesco Ltd.

CIK 0000914208

$320M1.7M0.03%Q1 2026 13

Boston Partners

CIK 0001386060

$273M1.3M0.24%Q2 2026 14

NORTHERN TRUST CORP

CIK 0000073124· Index

$265M1.4M0.04%Q1 2026 15

SUSQUEHANNA INTERNATIONAL GROUP, LLP

CIK 0001446194· Market maker

$263M1.4M0.03%Q1 2026 16

UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC

CIK 0000861177

$253M1.4M0.05%Q1 2026 17

Legal & General Group Plc

CIK 0000764068

$247M1.3M0.06%Q1 2026 18

GOLDMAN SACHS GROUP INC

CIK 0000886982

$216M1.2M0.02%Q1 2026 19

T. Rowe Price Investment Management, Inc.

CIK 0001897612

$213M1.2M0.15%Q1 2026 20

BANK OF AMERICA CORP /DE/

CIK 0000070858

$212M1.2M0.02%Q1 2026

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