MGNIMagnite, Inc. · Insider ownership research

Magnite, Inc. insiders sold $27.0M in the past 12 months. How much of their stake is that?

96% was sold under disclosed trading plans, 4% with no plan disclosed. The largest seller, Michael Barrett (CEO, Director), sold $13.6M. 60% of these sales were shares from exercising options.Share-of-stake figures for this company are being verified and will be added when that check is finished. Why

Updated Oct 16, 2026 from SEC filings · covers Oct 17, 2025 to Oct 16, 2026

$1.1M

sold with no plan disclosed, past 12 months

96%

of sales were under disclosed trading plans, past 12 months

13 of 17

officers and directors sold shares, past 12 months

Is this normal? In line with the past 5 years. 13 insiders sold; the average is 10 a year. Year by year

Latest filing: Filed Oct 14 for a sale on Oct 12. Paul Caine sold 12K shares ($316K) under a disclosed plan. Filing

SEC ownership filings: 93 filed in the 12 months to Oct 16, 2026; 800 on record since Apr 1, 2014 · See the evidence

What stands out

Selling picked up in the last 90 days: officers and directors sold 699K shares, against an average of 197K per 90 days earlier in the period. Most of it was Michael Barrett (294K shares in the last 90 days) and Sean Buckley (78K shares in the last 90 days); 95% of these sales were under disclosed plans.Michael Barrett: largest recent sale, Aug 6, 2026 · Sean Buckley: largest recent sale, Aug 6, 2026

A share of stake is shown for 0 of the 13 officers and directors who sold. 17 are left out

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Left out: Katie Evans, David Day, Adam Soroca, Sean Buckley, Michael Barrett, David Buonasera, Rachel Lam, Aaron Saltz, Douglas Knopper, Paul Caine, Sarah Harden, James Rossman, Brian Gephart, David Pearson, Diane Yu, Robert Spillane and Haas Sullivan (share of stake is being verified).

Disclosed company stock is not an insider's whole wealth.

Who sold, and how much of their stake

Officers and directors, past 12 months. Their share of stake is being verified and is not shown yet; amounts and trading plans are below.

Michael Barrett

CEO, Director

Not confirmed

Share of stake not shown: share of stake is being verified. Why

$13.6MDisclosed plan

Sean Buckley

President, Revenue & Market Strategy

Not confirmed

Share of stake not shown: share of stake is being verified. Why

$2.8MDisclosed plan

Douglas Knopper

Director

Not confirmed

Share of stake not shown: share of stake is being verified. Why

$2.7MDisclosed plan

Katie Evans

President, Product & Operations

Not confirmed

Share of stake not shown: share of stake is being verified. Why

$1.8MDisclosed plan

Sarah Harden

Director

Not confirmed

Share of stake not shown: share of stake is being verified. Why

$1.2MDisclosed plan

Selling by month

Officers and directors, Oct 2025 to Oct 2026. Each sale is counted once: under a disclosed plan, else to cover taxes, else no plan disclosed.

Disclosed planNo plan disclosedOne dollar scale for every month; the tallest bar is labeled

Recent activity

Past 30 days, Sep 17, 2026 to Oct 16, 2026

Oct 12, 2026Paul Caine sold 13K shares ($316K) under a disclosed trading plan.

Who	Shares	Price	% of total stake	Total stake after	Trade date	Filed
Paul Caine Director	12,500	$25.29	n/a	n/a	Oct 12, 2026	Oct 14, 2026

Sep 17, 20262 directors sold 45K shares ($1.2M) under a disclosed trading plan.

Who	Shares	Price	% of total stake	Total stake after	Trade date	Filed
Douglas Knopper Director	37,337	$26.28	n/a	n/a	Sep 17, 2026	Sep 18, 2026
Paul Caine Director	7,500	$26.50	n/a	n/a	Sep 17, 2026	Sep 18, 2026

"% of total stake" is the shares in an event against all the vested shares the person held that day, across every share class and holding entity, after that day's vesting. "n/a" means the person's holdings are not confirmed, or the row is a purchase. "Holdings record incomplete" means more shares were sold than the filings show the person held that day, so a percentage would be wrong.

Common questions

Is the Magnite, Inc. CEO selling stock?

Yes. Michael Barrett sold 686K shares ($13.6M) in the past 12 months, all of it under a trading plan disclosed in the filings.

Why are Magnite, Inc. insiders selling?

Filings rarely give a reason, and we don't guess at one. What they show is how the sales were made: 96% of sales by value ran under 10b5-1 trading plans disclosed in the filings and 4% had no disclosed plan. A trading plan schedules sales in advance.

Are any Magnite, Inc. insiders buying?

No. Officers and directors reported no purchases in the past 12 months.

The evidence

Who sold13 officers and directors: amount, % of holdings, trading plan

Who sold	Amount	% of holdings	Trading plan
Michael Barrett CEO, Director	$13.6M 686K shares	Not confirmed share of stake is being verified. Why	Disclosed plan
Sean Buckley President, Revenue & Market Strategy	$2.8M 123K shares	Not confirmed share of stake is being verified. Why	Disclosed plan
Douglas Knopper Director	$2.7M 123K shares	Not confirmed share of stake is being verified. Why	Disclosed plan
Katie Evans President, Product & Operations	$1.8M 77K shares	Not confirmed share of stake is being verified. Why	Disclosed plan
Sarah Harden Director	$1.2M 49K shares	Not confirmed share of stake is being verified. Why	Disclosed plan
Paul Caine Director	$1.1M 48K shares	Not confirmed share of stake is being verified. Why	Disclosed plan
Aaron Saltz Chief Legal Officer	$936K 40K shares	Not confirmed share of stake is being verified. Why	Disclosed plan
David Buonasera Chief Technology Officer	$841K 41K shares	Not confirmed share of stake is being verified. Why	Disclosed plan
Adam Soroca Chief Product Officer	$685K 49K shares	Not confirmed share of stake is being verified. Why	Disclosed plan
Robert Spillane Director	$557K 33K shares	Not confirmed share of stake is being verified. Why	No plan disclosed
Brian Gephart Chief Financial Officer	$308K 12K shares	Not confirmed share of stake is being verified. Why	No plan disclosed
Rachel Lam Director	$242K 10K shares	Not confirmed share of stake is being verified. Why	No plan disclosed
David Pearson Director	$168K 11K shares	Not confirmed share of stake is being verified. Why	Disclosed plan

The full ownership picture0 of 17 officers and directors confirmed

Vested shares across all share classes, held directly and through trusts, LLCs and family members, as reported on SEC Forms 3, 4 and 5. Unvested awards and options are never counted as owned shares.

Insider

Held Oct 16, 2025

Sold

Held Oct 16, 2026

Still held

Katie Evans

!

Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for Katie Evans are complete.

President, Product & Operations

n/a

−77K

n/a

n/a

Vesting, gifts, unvested awards and holding lines for Katie Evans

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Katie Evans are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

−87Kwithheld by the company for taxes

David Day

!

Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for David Day are complete.

Chief Financial Officer

n/a

0

n/a

n/a

Vesting, gifts, unvested awards and holding lines for David Day

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for David Day are complete; balances and unit counts will be added when the check is finished.

−26Kgifted (net of own trusts)

−107Kwithheld by the company for taxes

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
44,784	$5.28	Apr 1, 2030	$896K

Estimate: options held × ($25.29 − strike price), using the most recent insider trade price on Form 4 (Oct 12, 2026), not a market close.

Adam Soroca

!

Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for Adam Soroca are complete.

Chief Product Officer

n/a

−49K

n/a

n/a

Vesting, gifts, unvested awards and holding lines for Adam Soroca

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Adam Soroca are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

−54Kwithheld by the company for taxes

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
80,001	$4.92	Feb 20, 2029	$1.6M

Estimate: options held × ($25.29 − strike price), using the most recent insider trade price on Form 4 (Oct 12, 2026), not a market close.

Sean Buckley

!

Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for Sean Buckley are complete.

President, Revenue & Market Strategy

n/a

−123K

n/a

n/a

Vesting, gifts, unvested awards and holding lines for Sean Buckley

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Sean Buckley are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

−93Kwithheld by the company for taxes

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
57,405	$13.90	Feb 1, 2032	$654K

Estimate: options held × ($25.29 − strike price), using the most recent insider trade price on Form 4 (Oct 12, 2026), not a market close.

Michael Barrett

!

Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for Michael Barrett are complete.

CEO, Director

n/a

−686K

n/a

n/a

Vesting, gifts, unvested awards and holding lines for Michael Barrett

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Michael Barrett are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

−166Kwithheld by the company for taxes

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
129,870	$9.20	Jan 2, 2034	$2.1M
81,374	$16.46	Jan 9, 2035	$719K
90,909	$16.23	Jan 1, 2036	$824K
293,968	$5.80	Mar 17, 2027	$5.7M

Estimate: options held × ($25.29 − strike price), using the most recent insider trade price on Form 4 (Oct 12, 2026), not a market close.

David Buonasera

!

Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for David Buonasera are complete.

Chief Technology Officer

n/a

−41K

n/a

n/a

Vesting, gifts, unvested awards and holding lines for David Buonasera

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for David Buonasera are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

−53Kwithheld by the company for taxes

Rachel Lam

!

Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for Rachel Lam are complete.

Director

n/a

−10K

n/a

n/a

Vesting, gifts, unvested awards and holding lines for Rachel Lam

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Rachel Lam are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Aaron Saltz

!

Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for Aaron Saltz are complete.

Chief Legal Officer

n/a

−40K

n/a

n/a

Vesting, gifts, unvested awards and holding lines for Aaron Saltz

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Aaron Saltz are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

−45Kwithheld by the company for taxes

Douglas Knopper

!

Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for Douglas Knopper are complete.

Director

n/a

−123K

n/a

n/a

Vesting, gifts, unvested awards and holding lines for Douglas Knopper

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Douglas Knopper are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Paul Caine

!

Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for Paul Caine are complete.

Director

n/a

−48K

n/a

n/a

Vesting, gifts, unvested awards and holding lines for Paul Caine

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Paul Caine are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Sarah Harden

!

Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for Sarah Harden are complete.

Director

n/a

−49K

n/a

n/a

Vesting, gifts, unvested awards and holding lines for Sarah Harden

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Sarah Harden are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

James Rossman

!

Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for James Rossman are complete.

Director

n/a

0

n/a

n/a

Vesting, gifts, unvested awards and holding lines for James Rossman

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for James Rossman are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Brian Gephart

!

Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for Brian Gephart are complete.

Chief Financial Officer

n/a

−12K

n/a

n/a

Vesting, gifts, unvested awards and holding lines for Brian Gephart

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Brian Gephart are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

−17Kwithheld by the company for taxes

David Pearson

!

Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for David Pearson are complete.

Director

n/a

−11K

n/a

n/a

Vesting, gifts, unvested awards and holding lines for David Pearson

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for David Pearson are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Diane Yu

!

Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for Diane Yu are complete.

Director

n/a

0

n/a

n/a

Vesting, gifts, unvested awards and holding lines for Diane Yu

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Diane Yu are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Robert Spillane

!

Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for Robert Spillane are complete.

Director

n/a

−33K

n/a

n/a

Vesting, gifts, unvested awards and holding lines for Robert Spillane

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Robert Spillane are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Haas Sullivan

!

Holdings and share of stake are being verified. Share-of-stake figures and holdings for this company are held back while they are verified. Sales and other transactions for Haas Sullivan are complete.

Chief Accounting Officer

n/a

0

n/a

n/a

Vesting, gifts, unvested awards and holding lines for Haas Sullivan

Holdings and share of stake are being verified. Sales, proceeds, plan and tax status and dates for Haas Sullivan are complete; balances and unit counts will be added when the check is finished.

0gifted (net of own trusts)

Holdings and share of stake for Magnite, Inc. are being verified, so no balances, unit counts or percentages are shown. Sales, proceeds, plan and tax status, titles and dates come straight from individual filings.

What explains the selling$27.0M of sales by plan status, purpose, seller and month

Officer and director open-market sales: $27.0M across 1,302,205 shares. Plan status and stated purpose are separate questions, and a sale can have both.

By plan status

Disclosed plan · $25.9M · 96%

4%

The lighter segment is sales with no plan disclosed in the filing ($1.1M), including tax-related sales outside a plan.

No plan disclosed · $1.1M

Sales with no 10b5-1 plan and no tax reference in the filing. $557K of it is Robert Spillane. No plan disclosed is a statement about the filing, not about why the sale happened. Largest such sale: Brian Gephart, Aug 10, 2026

Taxes

622,063 shares ($9.5M) were withheld by the company for taxes, which isn't a market sale.

Seller	Shares sold	Proceeds	Under a disclosed plan	Share of total	Sales dates
Michael Barrett CEO, Director	686K	$13.6M	100%	51%	Jun 15, 2026 to Aug 6, 2026
Sean Buckley President, Revenue & Market Strategy	123K	$2.8M	100%	10%	Nov 18, 2025 to Aug 18, 2026
Douglas Knopper Director	123K	$2.7M	100%	10%	Jun 10, 2026 to Sep 17, 2026
Katie Evans President, Product & Operations	77K	$1.8M	100%	7%	Aug 6, 2026 to Sep 11, 2026
Sarah Harden Director	49K	$1.2M	100%	4%	Aug 26, 2026 to Aug 28, 2026
Paul Caine Director	48K	$1.1M	100%	4%	Oct 24, 2025 to Oct 12, 2026
Aaron Saltz Chief Legal Officer	40K	$936K	100%	3%	Sep 10, 2026 to Sep 10, 2026
David Buonasera Chief Technology Officer	41K	$841K	100%	3%	Jun 1, 2026 to Sep 14, 2026
Adam Soroca Chief Product Officer	49K	$685K	100%	3%	Nov 18, 2025 to Feb 18, 2026
Robert Spillane Director	33K	$557K	0%	2%	Nov 21, 2025 to Sep 14, 2026
Brian Gephart Chief Financial Officer	12K	$308K	0%	1%	Aug 10, 2026 to Aug 10, 2026
Rachel Lam Director	10K	$242K	0%	0.9%	Aug 10, 2026 to Aug 10, 2026
David Pearson Director	11K	$168K	100%	0.6%	Jun 10, 2026 to Jun 10, 2026

Sales by month

Month	Sale proceeds	Disclosed plan	To cover taxes	No plan disclosed
Oct 2025	$100K	$100K	$0	$0
Nov 2025	$413K	$235K	$0	$178K
Dec 2025	$283K	$283K	$0	$0
Jan 2026	$0	$0	$0	$0
Feb 2026	$258K	$258K	$0	$0
Mar 2026	$0	$0	$0	$0
Apr 2026	$0	$0	$0	$0
May 2026	$133K	$0	$0	$133K
Jun 2026	$7.8M	$7.8M	$0	$0
Jul 2026	$1.5M	$1.5M	$0	$0
Aug 2026	$12.1M	$11.6M	$0	$550K
Sep 2026	$4.0M	$3.8M	$0	$246K
Oct 2026	$316K	$316K	$0	$0

Is this normal? Selling year by year5 earlier years to compare with

In line with the past 5 years. 13 insiders sold; the average is 10 a year.

12 months ending	Shares sold	Insiders who sold	Proceeds
Oct 16, 2026 Latest 12 months	1.30M	13	$27.0M
Oct 16, 2025 1 year earlier	2.10M	14	$41.7M
Oct 16, 2024 2 years earlier	701K	9	$8.6M
Oct 17, 2023 3 years earlier	679K	10	$7.3M
Oct 17, 2022 4 years earlier	51K	2	$799K
Oct 17, 2021 5 years earlier	1.71M	13	$48.8M

Open-market sales (Form 4 code S) by people who were officers or directors, in split-adjusted shares. Earlier years include people who have since left. A sale that an outside holder also reports (a family trust, a fund) is counted with outside holders in every year. Shares, not dollars, are compared, so a change in the stock price doesn't look like a change in selling. Years the filings don't fully cover are shown but left out of the average.

Known gaps and uncertainty17 officers and directors not confirmed

Holdings and share of stake are being verified. Balances, unit counts and every share-of-stake figure for Magnite, Inc. are held back until that check is finished. Sales, proceeds, plan and tax status, titles and dates come straight from individual filings and are complete.

External context: we only cite outside events when a documented connection exists. None is shown for this period.

Sources and methodology800 filings on record, 93 filed in the 12-month period, and how we read them

All 800 Forms 3, 4 and 5 on record for Magnite, Inc. (SEC CIK 1595974), filed from Apr 1, 2014 to Oct 14, 2026; 93 of them were filed in the 12 months this page covers, retrieved from SEC EDGAR on Oct 16, 2026. Prices are the ones reported in each filing, often weighted averages.

Holdings. Each holding line (a share class plus an owner, such as a trust or LLC) carries its last reported balance forward. Entities first reported during the period start at zero, so transfers between an insider's own trusts don't count as selling. Lines not reported for three years or more are listed separately and left out of totals.

Sales. A sale counts as under a 10b5-1 plan if its footnote cites one or the filing's Rule 10b5-1 box is checked, and as tax-related if its footnote cites tax obligations or sell-to-cover. Shares withheld by the company for taxes are listed separately. Sales with neither attribute are labeled "no plan disclosed".

Full methodology

Former or inactive filers (23)No filing in 18 months; last reported balances, not in any total

Name	Last filed	Last reported balance
Robert Frankenberg	Jun 16, 2023	119,090 shares, last reported balance as of Jun 14, 2023
Lisa Troe	Jun 12, 2023	114,218 shares, last reported balance as of Jun 8, 2023
James Dove	Aug 17, 2022	191,071 shares, last reported balance as of Aug 15, 2022
Joseph Prusz	Feb 16, 2022	311,083 shares, last reported balance as of Feb 15, 2022
Thomas Kershaw	May 19, 2021	540,430 shares, last reported balance as of May 17, 2021
Shawna Hughes	May 19, 2021	178,129 shares, last reported balance as of May 17, 2021
Eve Filip	Jul 31, 2020	213,207 shares, last reported balance as of Jul 29, 2020
Blima Tuller	Jun 5, 2020	143,055 shares, last reported balance as of May 21, 2020
Mark Zagorski	Apr 3, 2020	236,269 shares, last reported balance as of Apr 1, 2020
Frank Addante	Mar 17, 2020	1,136,069 shares, last reported balance as of Mar 16, 2020
Jonathan Feldman	Jan 21, 2020	79,771 shares, last reported balance as of Jan 16, 2020
Lewis Coleman	May 17, 2019	55,703 shares, last reported balance as of May 15, 2019
Sumant Mandal	Feb 26, 2019	44,988 shares, last reported balance as of Feb 25, 2019
Sumant Mandal	Feb 26, 2019	16,669,474 shares, last reported balance as of Feb 25, 2019
Brian Copple	May 17, 2018	413,374 shares, last reported balance as of May 15, 2018
Gregory Raifman	May 17, 2017	420,459 shares, last reported balance as of May 15, 2017
Harry Patz Jr.	Jan 5, 2017	No balance on record
James Richter	Nov 3, 2016	117,316 shares, last reported balance as of Oct 20, 2016
Todd Tappin	May 26, 2016	441,327 shares, last reported balance as of May 25, 2016
Clearstone Venture Management III, L.L.C.	Oct 28, 2015	110,640 shares, last reported balance as of Apr 7, 2014
Xii Mayfield	Mar 4, 2015	3,587,675 shares, last reported balance as of Mar 3, 2015
Jarl Mohn	Apr 11, 2014	377,133 shares, last reported balance as of Apr 7, 2014
NEWS CORP	Apr 9, 2014	4,746,349 shares, last reported balance as of Apr 7, 2014

Spotted something wrong on this page? Report an error. We check every report against the SEC filing and list what we fix in the corrections log.