MGNI Form 4: Katie Seitz Evans sells 21,509 shares; post-sale ownership 394,089

Rhea-AI Filing Summary

Magnite, Inc. (MGNI) reporting person Katie Seitz Evans, President, Operations, reported an insider sale. On 08/27/2025 Ms. Evans disposed of 21,509 shares of Magnite common stock at a weighted average price of $25.52 per share (sales occurred at prices ranging from $25.52 to $25.58). After the transaction she beneficially owned 394,089 shares. The Form 4 was filed as a single reporting person form and signed by an attorney-in-fact, Aaron Saltz, on 08/29/2025. The filer offered to provide the breakdown of shares sold at each price on request.

Positive

• Timely disclosure of the insider sale via Form 4 filed and signed by attorney-in-fact within two days of the transaction
• Transparency through a footnote offering to provide the breakdown of the number of shares sold at each separate price

Negative

• Insider sale of 21,509 shares on 08/27/2025 at a weighted average price of $25.52
• Reduction in beneficial ownership to 394,089 shares following the reported transaction

Insights

Corporate Governance Expert

TL;DR: Insider sale disclosed promptly; reporting and offer to provide detailed price breakdown indicate compliance, but sale size is notable relative to holdings.

The Form 4 shows a routine disclosure of an officer sale rather than an award exercise or gift. The filing includes a footnote explaining the weighted average price and offers to provide per-trade details, which supports transparency and compliance with Section 16 reporting obligations. The disposed amount (21,509 shares) compared with post-sale beneficial ownership (394,089 shares) suggests a meaningful but not controlling reduction in holdings. From a governance perspective, timely and complete disclosure reduces regulatory risk.

Securities Analyst

TL;DR: Insider sold 21,509 shares at a weighted average $25.52; the trade is material to holdings but provides limited signal on company fundamentals.

The transaction is an outright sale (transaction code S) executed on 08/27/2025 at a weighted average price of $25.52, with reported prices ranging to $25.58. Post-transaction beneficial ownership is 394,089 shares. While the sale reduces insider exposure by roughly 5.5%, the Form 4 contains no accompanying explanation for the sale (e.g., diversification, tax, 10b5-1 plan). As a standalone disclosure, it is informative about insider activity but does not directly indicate changes to company operations or financials.

SEC Form 4

FORM 4

UNITED 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
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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

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^*

Evans Katie Seitz

(Last) (First) (Middle)

C/O MAGNITE, INC.

1250 BROADWAY, 15TH FLOOR

(Street)

NEW YORK NY 10001

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
MAGNITE, INC. [ MGNI ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	President, Operations

3. Date of Earliest Transaction (Month/Day/Year)
08/27/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

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)
			Code	V	Amount	(A) or (D)	Price
Common Stock	08/27/2025		S		21,509	D	$25.52(1)	394,089	D

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)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $25.52 to $25.58, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote to this Form 4.

	/s/ Aaron Saltz, attorney-in-fact	08/29/2025
	** Signature of Reporting Person	Date
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.

FAQ

What did the Form 4 for MGNI report?

The Form 4 reports that Katie Seitz Evans sold 21,509 shares of Magnite common stock on 08/27/2025 at a weighted average price of $25.52.

How many Magnite shares does the reporting person own after the sale?

After the reported transaction the reporting person beneficially owns 394,089 shares.

What prices were the sold shares executed at?

The Form 4 footnote states the shares were sold at prices ranging from $25.52 to $25.58, and the reported price is a weighted average of those trades.

Who signed the Form 4 filing for the reporting person?

The Form 4 was signed on behalf of the reporting person by Aaron Saltz, attorney-in-fact on 08/29/2025.

What transaction code was used on the Form 4?

The sale is reported with transaction code S, indicating a sale of securities.

Did the filer indicate an intention to provide more trade detail?

Yes. The filer offered to provide, upon request, the number of shares sold at each separate price within the stated range.