13F Insight
DOSSIER · 13F Holders · Q1 2026Technology · Services-Computer Programming, Data Processing, Etc.Cheap mega-capRe-rated
MGNI

MAGNITE INC

310 institutions still hold MAGNITE INC as of Q1 2026. Tracked across SEC 13F-HR filings, with insider and 13D/G activity surfaced alongside.

CUSIP 55955D100·Services-Computer Programming, Data Processing, Etc.·310 13F holders·last filed Mar 31, 2026
Market cap
—
▼ 9.9%
vs prior quarter
13F value held
$1.0B
73.0% inst. owned
of float
Holders
310
+51 QoQ
filers reporting
Activity
+53 / −57
+816 added · −822 reduced
this quarter
Concentration
13.20%
BlackRock, Inc. #1
top holder share
AI Holders Summary · Q1 2026

310 institutions reported MGNI in Q1 2026. BlackRock, Inc. leads at 13.2% of the visible book. +51 net new institutions vs prior quarter — accumulation reading.

Top holders

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

#HolderValueShares% port.Quarter
01
BlackRock, Inc.
CIK 0002012383
$138M11.7M0.00%Q1 202602
WELLINGTON MANAGEMENT GROUP LLP
CIK 0000902219
$109M9.2M0.02%Q1 202603
Vanguard Portfolio Management
CIK 0002100121
$92M7.7M0.00%Q1 202604
VANGUARD CAPITAL MANAGEMENT LLC
CIK 0002100119· Index
$74M6.2M0.00%Q1 202605
Capital Research Global Investors
CIK 0001422848
$60M5.0M0.01%Q1 202606
Boston Partners
CIK 0001386060
$56M4.7M0.06%Q1 202607
AMERICAN CENTURY COMPANIES INC
CIK 0000748054
$55M4.6M0.03%Q1 202608
FMR LLC
CIK 0000315066
$54M4.5M0.00%Q1 202609
DIMENSIONAL FUND ADVISORS LP
CIK 0000354204· Quasi-passive
$47M4.0M0.01%Q1 202610
Nuveen, LLC
CIK 0001871926
$43M3.6M0.01%Q1 202611
GEODE CAPITAL MANAGEMENT, LLC
CIK 0001214717· Index
$42M3.6M0.00%Q1 202612
Nine Ten Capital Management LLC
CIK 0001635236
$41M3.5M13.14%Q1 202613
Edenbrook Capital, LLC
CIK 0001666682
$40M3.4M12.57%Q1 202614
STATE STREET CORP
CIK 0000093751
$38M3.2M0.00%Q1 202615
325 CAPITAL LLC
CIK 0001873893
$33M2.0M11.40%Q4 202516
Granahan Investment Management, LLC
CIK 0001026710
$30M2.6M1.47%Q1 202617
CITADEL ADVISORS LLC
CIK 0001423053
$28M1.7M0.00%Q4 202518
Ophir Asset Management Pty Ltd
CIK 0001844640
$25M2.1M2.93%Q1 202619
Caption Management, LLC
CIK 0001706766
$23M1.9M0.13%Q1 202620
JANE STREET GROUP, LLC
CIK 0001595888· Market maker
$21M1.8M0.00%Q1 2026
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