MGNI Magnite, Inc.

NASDAQ
$23.97

Magnite, Inc. (MGNI) Institutional Ownership

What the institutions did with MGNI last quarter, from their 13F filings. Counting managers rather than shares is the point: a single index fund adding to a position tells you far less than four hundred separate managers all deciding to. Positions as reported for the quarter ended June 30, 2026.

Managers compared
343
filed both this quarter and last
Managers holding
306
+13 on the quarter
Buyers
166
50 opened new
Sellers
127
37 sold out entirely
Buyer share
56.7%
of managers who traded it
Breadth
+13.3
net buyers, as a share of those trading

Every manager below opens. Subscribers can see any firm's whole portfolio — every position, its weight, and what they bought, trimmed and exited last quarter.

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Ownership map

Each block is one manager, sized by shares held and colored by how much they moved the position last quarter. Green added, red cut, grey stood pat.

Cut Unchanged Added Color saturates at ±50%.

Largest holders

Manager Shares % of reported
BlackRock, Inc. 12.7M 8.9%
VANGUARD PORTFOLIO MANAGEMENT LLC 8.2M 5.8%
FMR LLC 7.8M 5.4%
VANGUARD CAPITAL MANAGEMENT LLC 6.2M 4.4%
WELLINGTON MANAGEMENT GROUP LLP 6.0M 4.2%
DIMENSIONAL FUND ADVISORS LP 5.3M 3.7%
Boston Partners 5.0M 3.5%
AMERICAN CENTURY COMPANIES INC 4.6M 3.2%
Capital Research Global Investors 3.9M 2.7%
Nuveen, LLC 3.8M 2.7%
GEODE CAPITAL MANAGEMENT, LLC 3.8M 2.7%
Edenbrook Capital, LLC 3.6M 2.5%
STATE STREET CORP 3.5M 2.5%
325 CAPITAL LLC 3.4M 2.4%
Nine Ten Capital Management LLC 3.3M 2.3%
Granahan Investment Management, LLC 3.1M 2.2%
CANADA PENSION PLAN INVESTMENT BOARD 3.0M 2.1%
JANE STREET GROUP, LLC 2.2M 1.5%
Park West Asset Management LLC 2.0M 1.4%
MORGAN STANLEY 2.0M 1.4%
Qube Research & Technologies Ltd 2.0M 1.4%
Blue Grotto Capital, LLC 1.7M 1.2%
KENNEDY CAPITAL MANAGEMENT LLC 1.7M 1.2%
NORTHERN TRUST CORP 1.6M 1.1%
ROYCE & ASSOCIATES LP 1.5M 1.0%

Largest changes

Manager Action Previous Current Change
FMR LLC Increased 4.5M 7.8M +3.3M
WELLINGTON MANAGEMENT GROUP LLP Reduced 9.2M 6.0M -3.1M
CANADA PENSION PLAN INVESTMENT BOARD Increased 46.1K 3.0M +2.9M
No Street GP LP Sold Out 1.6M 0 -1.6M
325 CAPITAL LLC Increased 2.0M 3.4M +1.4M
Park West Asset Management LLC Increased 598.4K 2.0M +1.4M
Qube Research & Technologies Ltd Increased 661.1K 2.0M +1.3M
DIMENSIONAL FUND ADVISORS LP Increased 4.0M 5.3M +1.3M
Capital Research Global Investors Reduced 5.0M 3.9M -1.2M
MORGAN STANLEY Increased 926.8K 2.0M +1.1M
BlackRock, Inc. Increased 11.7M 12.7M +1.1M
Schonfeld Strategic Advisors LLC Reduced 1.6M 562.2K -1.0M
First Eagle Investment Management, LLC Increased 450.3K 1.3M +891.3K
Balyasny Asset Management L.P. Reduced 1.5M 666.6K -833.9K
Edenbrook Capital, LLC Increased 2.8M 3.6M +757.6K
Ophir Asset Management Pty Ltd Reduced 2.1M 1.5M -668.0K
AMERIPRISE FINANCIAL INC New 0 619.6K +619.6K
Man Group plc Reduced 664.0K 53.1K -610.9K
CITADEL ADVISORS LLC Reduced 1.1M 472.9K -580.0K
BANK OF MONTREAL /CAN/ New 0 533.8K +533.8K
JANE STREET GROUP, LLC Increased 1.7M 2.2M +531.0K
Granahan Investment Management, LLC Increased 2.6M 3.1M +529.8K
Pacer Advisors, Inc. Sold Out 501.6K 0 -501.6K
EVR Research LP New 0 480.0K +480.0K
VANGUARD PORTFOLIO MANAGEMENT LLC Increased 7.7M 8.2M +471.1K
MILLENNIUM MANAGEMENT LLC Reduced 1.2M 764.8K -469.6K
Capital World Investors Sold Out 456.7K 0 -456.7K
CenterBook Partners LP Reduced 564.2K 117.6K -446.6K
Jump Financial, LLC New 0 428.0K +428.0K
Blue Grotto Capital, LLC Increased 1.3M 1.7M +378.0K
STATE STREET CORP Increased 3.2M 3.5M +364.9K
TWO SIGMA INVESTMENTS, LP Reduced 394.9K 42.7K -352.2K
Trexquant Investment LP New 0 333.4K +333.4K
Alyeska Investment Group, L.P. New 0 326.8K +326.8K
MARSHALL WACE, LLP Increased 42.5K 341.9K +299.4K
UBS Group AG Increased 450.3K 746.4K +296.0K
Boston Partners Increased 4.7M 5.0M +294.0K
QVT Financial LP Increased 453.9K 747.4K +293.5K
Caption Management, LLC Reduced 405.1K 145.6K -259.5K
GEODE CAPITAL MANAGEMENT, LLC Increased 3.6M 3.8M +236.2K
NORTHERN TRUST CORP Increased 1.3M 1.6M +230.8K
Nine Ten Capital Management LLC Reduced 3.5M 3.3M -220.0K
Pillsbury Lake Capital LLC New 0 217.8K +217.8K
Maestria Partners LLC Reduced 1.4M 1.2M -205.1K
Nuveen, LLC Increased 3.6M 3.8M +204.8K
Occam Crest Management LP New 0 195.0K +195.0K
WEDGE CAPITAL MANAGEMENT L L P/NC Sold Out 189.8K 0 -189.8K
SEI INVESTMENTS CO Reduced 350.9K 165.6K -185.3K
Kopion Asset Management, LLC Reduced 855.9K 674.5K -181.5K
Walleye Trading LLC Sold Out 179.4K 0 -179.4K
GREAT LAKES ADVISORS, LLC New 0 176.6K +176.6K
DEAN INVESTMENT ASSOCIATES, LLC New 0 167.9K +167.9K
S SQUARED TECHNOLOGY, LLC Increased 402.9K 567.9K +165.0K
CLOUGH CAPITAL PARTNERS L P New 0 159.6K +159.6K
SUSQUEHANNA INTERNATIONAL GROUP, LLP Increased 307.8K 461.8K +154.0K
Concentric Capital Strategies, LP New 0 146.7K +146.7K
Manatuck Hill Partners, LLC Increased 310.0K 450.0K +140.0K
Brevan Howard Capital Management LP Sold Out 133.2K 0 -133.2K
TWINBEECH CAPITAL LP Sold Out 132.4K 0 -132.4K
ALGERT GLOBAL LLC Reduced 269.0K 137.5K -131.5K

13F filings are due 45 days after quarter end and cover long positions in U.S.-listed equities only, so this is a lagged and partial picture: shorts, bonds and foreign listings never appear. Options positions are excluded here rather than folded into the share counts. Political ownership is coming.