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MGNI in the 13F filings

Magnite Inc · CUSIP 55955D100

Sector · Software and IT servicesTheme · Internet, programming and data services
Quarter
Q2 2026Q1 2026Q4 2025Q3 2025Q2 2025Q1 2025Q4 2024Q3 2024Q2 2024Q3 2023Q2 2023Q1 2023
Quarter end
30 Jun 2026
the date the book describes
Filed
27 Oct 2026
latest of these filings; the earliest 3 Aug 2026
Managers listing it
26
at least, of 95 tracked, among listed positions
Comparable managers
91
filed both Q1 2026 and Q2 2026; 3 listed it in both
Shares listed
25,472,916
combined, among listed positions
Reported value
$482m
combined, at the quarter end

AllianceBernstein LP. Values in this filing are at the previous quarter end's prices; its share count is the quarter end's.

Among the 91 comparable managers: 13 buyers (opened or added shares) and 16 sellers (trimmed or exited), at least, among listed positions. Their net change in shares was -4,283,548.

Managers listing MGNI in Q2 2026

Share of 13F value is the position’s reported value over everything the manager reported that quarter. The share change is against Q1 2026, and only where both filings list the position. A rise in value with no rise in shares is the price, not buying.

26 of 26 holders

ActionFiling
Fidelity (FMR LLC)7,759,426$147munder 0.1%Added+3,252,00713 Aug 2026 (the filing on sec.gov)
Wellington Management Group LLP6,044,492$115munder 0.1%Trimmed-3,146,58514 Aug 2026 (the filing on sec.gov)
Capital Research Global Investors3,869,159$73munder 0.1%Trimmed-1,151,13012 Aug 2026 (the filing on sec.gov)
Jane Street Group LLC2,199,191$42munder 0.1%Added+531,03114 Aug 2026 (the filing on sec.gov)
Millennium Management LLC764,819$15munder 0.1%Trimmed-469,63814 Aug 2026 (the filing on sec.gov)
First Eagle Investment Management LLC670,788$13munder 0.1%Added+220,5005 Aug 2026 (the filing on sec.gov)
Balyasny Asset Management LLC666,554$13munder 0.1%Trimmed-833,88914 Aug 2026 (the filing on sec.gov)
Schonfeld Strategic Advisors LLC562,195$11munder 0.1%Trimmed-1,042,84614 Aug 2026 (the filing on sec.gov)
Citadel Advisors LLC472,865$9.0munder 0.1%Trimmed-580,0432 Sep 2026 (the filing on sec.gov)
Susquehanna International Group LLP461,849$8.8munder 0.1%Added+154,04414 Aug 2026 (the filing on sec.gov)
Marshall Wace LLP341,864$6.5munder 0.1%Added+299,39613 Aug 2026 (the filing on sec.gov)
ExodusPoint Capital Management LP271,869$5.2munder 0.1%Added+122,65014 Aug 2026 (the filing on sec.gov)
Squarepoint Ops LLC230,234$4.4munder 0.1%Trimmed-70,70014 Aug 2026 (the filing on sec.gov)
Invesco Ltd222,213$4.2munder 0.1%Trimmed-39,15714 Aug 2026 (the filing on sec.gov)
T. Rowe Price Associates Inc199,445$3.8munder 0.1%Added+34,00514 Aug 2026 (the filing on sec.gov)
AQR Capital Management LLC176,599$3.4munder 0.1%Added+55,38714 Aug 2026 (the filing on sec.gov)
Winton Group Ltd121,900$2.3m0.07%Newnew7 Aug 2026 (the filing on sec.gov)
AllianceBernstein LP144,845$1.7munder 0.1%Trimmed-78,34614 Aug 2026 (the filing on sec.gov)
GAMCO Investors Inc63,101$1.2munder 0.1%Added+2,44812 Aug 2026 (the filing on sec.gov)
Janus Henderson Group Ltd58,423$1.1munder 0.1%Held014 Aug 2026 (the filing on sec.gov)
Man Group PLC53,054$1.0munder 0.1%Trimmed-610,90314 Aug 2026 (the filing on sec.gov)
Two Sigma Investments LP42,659$810kunder 0.1%Trimmed-352,19714 Aug 2026 (the filing on sec.gov)
D. E. Shaw & Co.35,719$678kunder 0.1%Newnew14 Aug 2026 (the filing on sec.gov)
Acadian Asset Management LLC24,288$459kunder 0.1%Added+20,60213 Aug 2026 (the filing on sec.gov)
Neuberger Berman Group LLC12,916$245kunder 0.1%Newnew27 Oct 2026 (the filing on sec.gov)
Page 1 of 2

Largest increases and reductions, by shares

Q1 2026 to Q2 2026, among managers that listed it in both quarters or opened it.

Increases

Reductions

New positions and exits

At least these many: a manager is shown exiting only where its own filing shows the position gone.

New (3)

Exited (4)

Ownership over time

Every quarter on file. A quarter-end value moves with the price as well as with the shares held; buyers and sellers count comparable managers, by shares.
1 in Q3 2024 to 5 in Q2 2026

Tracked managers listing it, at least.

024620212022202320252026
the quarter shown share split complete books; unmarked quarters rest on listed positionsClick a quarter to open it.
MGNI by quarter
QuarterHoldersReported valueBuyersSellers
Q4 20201$5.7mn.a.n.a.
Q1 20212$94mn.a.n.a.
Q2 20215$88mn.a.n.a.
Q3 20213$43mn.a.n.a.
Q4 20214$38mn.a.n.a.
Q1 20221$1.2mn.a.n.a.
Q2 20222$1.9mn.a.n.a.
Q3 20223$5.4mn.a.n.a.
Q4 20221$4.2mn.a.n.a.
Q1 20232$3.1mn.a.n.a.
Q2 20232$6.6mn.a.n.a.
Q3 20231$1.7mn.a.n.a.
Q2 20241$21m10
Q3 20241$50m10
Q4 20242$129m20
Q1 20253$163m30
Q2 20256$520m32
Q3 20252$165m03
Q4 20254$367m1217
Q1 20263$84m227
Q2 20265$104m1316

Compare with…

Holders over time, buyers and sellers, and the managers holding both, side by side for up to four stocks.

MGNI and GOOGL →MGNI and META →MGNI and SPCX →Choose a stock to compare with MGNI →

How much of the picture this is

A 13F is a manager’s long US-listed equity book at a quarter end, filed up to 45 days later. It shows no shorts, cash, bonds or performance, and it is never today’s portfolio. Large books are listed to their largest positions, so a manager missing from this table may still hold a small position below that line. These are 95 tracked managers, not the institutional market.

Which funds own MGNI, latest filings →Back to the 13F Explorer →