$MGNI

$22.26 +$0.44 (2.01%) After hours

$MGNI Overview Financial Statements SEC Filings Executives News Red Flags Capital Raising Ownership Insider Transactions Congressional Trades

Ownership

13F as of Q2 2026 · 143.4M shares outstanding

Who owns MGNI?

By type of holder

Institutions 98.3% Insiders 1.7% Everyone else 0.0%

Concentration Top 10 holders own 44.3%

BlackRock, Inc. 8.9% · Wellington Management Group LLP 4.2%

Institutional ownership

98.3%

+6.6 pts vs last qtr

Institutional holders

306

+11 vs last qtr

Net shares bought

+9.5M

by institutions in Q2 2026

New / sold out

53 / 42

positions opened vs closed

How is ownership changing?

Institutions, last 8 quarters

Biggest buyers in Q2 2026

FMR LLC +3.3M
Canada Pension Plan Investment Board +2.9M

Biggest sellers in Q2 2026

Wellington Management Group LLP −3.1M
No Street GP LP SOLD OUT −1.6M

Who is planning to sell?

Notices of proposed sale, last 12 months

$29.4M

59 notices from 15 people

Shares covered

1.5M

1.04% of the company

Arranged in advance

88%

of the value is under a 10b5-1 plan

Under a 10b5-1 plan No plan

Largest proposed sellers

Michael G Barrett Officer 10b5-1 $13.6M
Adam L Soroca Former officer $3.21M

Every notice on Red Flags →

A Form 144 is notice of a planned sale, not the sale itself. What insiders actually sold is on Insider Transactions.

Is your stake being diluted?

Diluted share count, FY2016–FY2025

+229.6%

+14.17% a year

Each share's claim on the business

−69.7%

shrank without buying or selling a share

Spent on buybacks vs paid in stock

$82.5M vs $443M

over 10 fiscal years

Diluted shares, split-adjusted

Buybacks Stock-based comp

How patient are the owners?

Institutional shares by how long they've been held

5+ years54% 3–5 years12% 1–3 years19% Under 1 year15%

Quarterly turnover

15.7%

of institutional shares changed hands

Top 10 managers, median time held

5 years

Super Investors

Investment managers reporting MGNI on Form 13F

Holder	Shares	% of company	Change vs last qtr	Held since	% of their book
B BlackRock, Inc.	12.7M	8.86%	+1.1M (+9.1%)	≤2021	0.0%
Shares held by quarter Peak holding12.7M (Q2'26) Change over 8 quarters+2.9M Share of the company8.860% BlackRock, Inc.'s full portfolio →
WM Wellington Management Group LLP	6.0M	4.21%	−3.1M (−34.2%)	2022	0.0%
Shares held by quarter Peak holding9.2M (Q1'26) Change over 8 quarters−535.2K Share of the company4.210% Wellington Management Group LLP's full portfolio →

BlackRock, Inc.

12.7M

% of company

8.86%

Change vs last qtr

+1.1M (+9.1%)

Held since

≤2021

Wellington Management Group LLP

6.0M

% of company

4.21%

Change vs last qtr

−3.1M (−34.2%)

Held since

2022

28 more super investors behind a free account

See every manager holding Magnite, Inc., how their position has changed, and how long they've held it.

Institutional Funds

Mutual funds and ETFs reporting MGNI on Form N-PORT; together they hold 40.6% of the company

Fund	Position value	Shares	% of company	% of the fund	As of
VT Vanguard Total Stock Market Index Fund Vanguard Index Funds	$82.1M	4.3M	3.02%	0.00%	June 30, 2026
SW SMALLCAP World Fund Inc SMALLCAP World Fund Inc	$72.1M	3.8M	2.65%	0.08%	June 30, 2026

Vanguard Total Stock Market Index Fund

Vanguard Index Funds

Position value

$82.1M

% of company

3.02%

% of the fund

0.00%

As of

June 30, 2026

SMALLCAP World Fund Inc

Position value

$72.1M

% of company

2.65%

% of the fund

0.08%

As of

June 30, 2026

23 more funds behind a free account

See every fund holding Magnite, Inc. and how much of the fund the position is.

Insiders and 5%+ holders

From Forms 3/4/5 and Schedules 13D/G

Holder	Shares	% of company	Change vs last qtr	8 quarters	Held since	% of their book
DD Day David Insider	452.9K	0.32%	—	—	—	—
Insider holdings come from Form 3/4/5 filings, which are not quarterly. Share of the company0.320% Day David's insider activity →
EK Evans Katie Seitz Insider	441.8K	0.31%	—	—	—	—
Insider holdings come from Form 3/4/5 filings, which are not quarterly. Share of the company0.310% Evans Katie Seitz's insider activity →

Day David

Insider

452.9K

% of company

0.32%

Change vs last qtr

—

Held since

—

Evans Katie Seitz

Insider

441.8K

% of company

0.31%

Change vs last qtr

—

Held since

—

15 more holders behind a free account

See every insider and 5%+ holder of Magnite, Inc..

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