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Magnite (MGNI) executive sells 19,233 shares under Rule 10b5-1 plan

Filing Impact
(Moderate)
Filing Sentiment
(Negative)
Form Type
4

Rhea-AI Filing Summary

Magnite, Inc. officer Sean Patrick Buckley reported an open-market sale of 19,233 shares of Common Stock at $19.00 per share. After this transaction, he directly holds 373,514 shares, indicating he retains a substantial equity position. The filing notes the sale was executed under a pre-arranged Rule 10b5-1 trading plan adopted on September 10, 2025, suggesting the trade was scheduled in advance rather than timed opportunistically.

Positive

  • None.

Negative

  • None.

Insights

Routine planned insider sale with significant remaining holdings.

Officer Sean Patrick Buckley conducted an open-market sale of 19,233 shares of Magnite, Inc. Common Stock at $19.00 per share. Following the transaction, he continues to hold 373,514 shares, which indicates an ongoing, sizable ownership stake.

The sale was carried out under a pre-arranged Rule 10b5-1 trading plan adopted on September 10, 2025. Such plans are typically set up in advance to systematically sell shares over time, which can reduce the informational value of the trade's specific timing for investors.

Given the remaining ownership and the planned nature of the transaction, this filing generally appears as a routine liquidity event rather than a major shift in insider sentiment. Future company filings may provide additional context on any broader pattern of insider trading activity.

Insider Buckley Sean Patrick
Role See Remarks
Sold 19,233 shs ($365K)
Type Security Shares Price Value
Sale Common Stock 19,233 $19.00 $365K
Holdings After Transaction: Common Stock — 373,514 shares (Direct, null)
Footnotes (1)
  1. [object Object]
Shares sold 19,233 shares Open-market sale of Common Stock
Sale price $19.00 per share Price for the 19,233-share sale
Shares held after transaction 373,514 shares Direct ownership following the sale
Transaction code S Sale in open market or private transaction
Rule 10b5-1 trading plan regulatory
"The reported transaction was effected pursuant to a Rule 10b5-1 trading plan"
A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.
open-market sale financial
"transaction_action": "open-market sale""
An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.
Common Stock financial
""security_title": "Common Stock""
Common stock represents ownership shares in a company, giving investors a stake in its success and a say in important decisions through voting rights. It is the most common type of stock traded on markets and can provide income through dividends, as well as potential for value growth. For investors, holding common stock means sharing in the company’s profits and risks.
Form 4 regulatory
"INSIDER FILING DATA (Form 4):"
Form 4 is a official document that company insiders, such as executives or major shareholders, file with regulators whenever they buy or sell company shares. It provides transparency about how those with inside knowledge are trading, helping investors see if insiders are confident in the company's prospects or may be selling for personal reasons. This information can influence investor decisions by revealing insiders' perspectives on the company's value.
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Form 4 Insider Transactions: What Each Field Means →
SEC Form 4
FORM 4UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940
OMB APPROVAL
OMB Number:3235-0287
Estimated average burden
hours per response:0.5
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
X
Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.
1. Name and Address of Reporting Person*
Buckley Sean Patrick
(Last)(First)(Middle)
C/O MAGNITE, INC.
1250 BROADWAY, 9TH FLOOR
(Street)
NEW YORK NEW YORK 10001
(City)(State)(Zip)
UNITED STATES
(Country)		2. Issuer Name and Ticker or Trading Symbol
MAGNITE, INC. [ MGNI ] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
Director10% Owner
XOfficer (give title below)Other (specify below)
See Remarks
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
06/17/2026		6. Individual or Joint/Group Filing (Check Applicable Line)
XForm filed by One Reporting Person
Form filed by More than One Reporting Person
4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year)2A. Deemed Execution Date, if any (Month/Day/Year)3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4)
CodeVAmount(A) or (D)Price
Common Stock06/17/2026S(1)19,233D$19373,514D
Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year)3A. Deemed Execution Date, if any (Month/Day/Year)4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 6. Date Exercisable and Expiration Date (Month/Day/Year)7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount or Number of Shares
Explanation of Responses:
1. The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on September 10, 2025.
Remarks:
President, Revenue & Market Strategy
/s/ Aaron Saltz, attorney-in-fact06/18/2026
** Signature of Reporting PersonDate
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

Source: View Original Filing on SEC EDGAR

FAQ

What did Magnite (MGNI) officer Sean Patrick Buckley do in this Form 4?

Sean Patrick Buckley reported an open-market sale of 19,233 shares of Magnite Common Stock at $19.00 per share. After the sale, he directly holds 373,514 shares, according to the Form 4 filing’s ownership table.

How many Magnite (MGNI) shares does Sean Patrick Buckley hold after the reported sale?

After the reported transaction, Sean Patrick Buckley directly holds 373,514 shares of Magnite Common Stock. This post-transaction figure comes from the Form 4 and shows he retains a substantial ongoing equity position in the company.

At what price were the Magnite (MGNI) shares sold in this insider transaction?

The 19,233 Magnite Common Stock shares were sold at a price of $19.00 per share. This price is explicitly listed in the Form 4 transaction details as the transaction price per share for the open-market sale.

Was the Magnite (MGNI) insider sale made under a Rule 10b5-1 trading plan?

Yes. The Form 4 footnote states the transaction was effected under a Rule 10b5-1 trading plan adopted by Sean Patrick Buckley on September 10, 2025. Such plans typically schedule trades in advance, reducing timing discretion.

Does the Form 4 show any option exercises or derivative transactions for Magnite (MGNI)?

No derivative transactions are listed in this Form 4. The derivative summary section is empty, and the filing only reports a single non-derivative open-market sale of Common Stock by the officer.

Is this Magnite (MGNI) insider transaction a buy or a sell?

This insider transaction is a sell. The Form 4 reports a transaction code “S” and describes it as an open-market sale of 19,233 shares of Magnite Common Stock at $19.00 per share.