AI Holders Summary · Q1 2026

37 institutions reported ATRA in Q1 2026. ADAGE CAPITAL PARTNERS GP, L.L.C. leads at 21.0% 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

ADAGE CAPITAL PARTNERS GP, L.L.C.

CIK 0001165408

$3M700K0.01%Q1 2026 02

MARSHALL WACE, LLP

CIK 0001318757

$3M149K0.00%Q4 2025 03

Redmile Group, LLC

CIK 0001425738

$2M442K0.14%Q1 2026 04

MACKENZIE FINANCIAL CORP

CIK 0000919859

$1M314K0.00%Q1 2026 05

VANGUARD CAPITAL MANAGEMENT LLC

CIK 0002100119· Index

$1M218K0.00%Q1 2026 06

BlackRock, Inc.

CIK 0002012383

$970K84K0.00%Q2 2026 07

Point72 Asset Management, L.P.

CIK 0001603466

$919K194K0.00%Q1 2026 08

ACADIAN ASSET MANAGEMENT LLC

CIK 0000916542

$617K131K0.00%Q1 2026 09

EcoR1 Capital, LLC

CIK 0001587114

$471K100K0.02%Q1 2026 10

GEODE CAPITAL MANAGEMENT, LLC

CIK 0001214717· Index

$313K66K0.00%Q1 2026 11

STATE STREET CORP

CIK 0000093751

$304K26K0.00%Q2 2026 12

CITADEL ADVISORS LLC

CIK 0001423053

$282K16K0.00%Q4 2025 13

UBS Group AG

CIK 0001610520

$237K50K0.00%Q1 2026 14

STALEY CAPITAL ADVISERS INC

CIK 0001106565

$237K50K0.01%Q1 2026 15

MILLENNIUM MANAGEMENT LLC

CIK 0001273087

$226K48K0.00%Q1 2026 16

JANE STREET GROUP, LLC

CIK 0001595888· Market maker

$160K34K0.00%Q1 2026 17

VANGUARD FIDUCIARY TRUST CO

CIK 0000933478· Index

$159K34K0.00%Q1 2026 18

BRIDGEWAY CAPITAL MANAGEMENT, LLC

CIK 0001107261

$155K33K0.00%Q1 2026 19

FMR LLC

CIK 0000315066

$77K16K0.00%Q1 2026 20

NORTHERN TRUST CORP

CIK 0000073124· Index

$58K12K0.00%Q1 2026

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