[Form 4] Magnite, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Magnite insider sale to cover taxes: Chief Accounting Officer Brian Gephart reported a non-discretionary sale of 2,961 shares of Magnite, Inc. (MGNI) on 08/18/2025 at $23.85 per share to satisfy tax withholding tied to the settlement of vested Restricted Stock Units. After the transaction, the reporting person beneficially owned 120,569 shares, held directly. The filing states the sale was mandated by the issuer's sell-to-cover election and was not a discretionary trade by the reporting person. The Form 4 was executed by an attorney-in-fact and contains no derivative transactions or other purchases.

Positive

• Transparent disclosure of the reason for the sale (sell-to-cover of vested RSUs), which clarifies the transaction was non-discretionary
• Reporting person retains a substantive stake with 120,569 shares after the sale, indicating continued alignment with shareholders

Negative

• None.

Insights

Securities Analyst

TL;DR Insider sold a small block of shares to satisfy tax withholding from vested RSUs; transaction appears routine and non-discretionary.

This Form 4 reports a modest sale of 2,961 common shares at $23.85 to cover tax obligations from vested restricted stock units. The seller is the Chief Accounting Officer and retained 120,569 shares post-transaction. The filing explicitly states the sale was mandated by the issuer's sell-to-cover policy and was not discretionary, which typically reduces signaling value to the market. No options, grants, or derivative transactions are reported, and the disclosure was signed by an attorney-in-fact.

Corporate Governance Expert

TL;DR Transaction aligns with standard payroll withholding on RSU settlement and raises no governance concerns from the filing details.

The filing documents a common administrative action: shares sold to satisfy tax withholding at RSU vesting. The reporting person remains a significant shareholder with 120,569 shares. The clear explanation that the sale was mandated by company policy supports compliance with Rule 10b5-1 disclosure norms and reduces the likelihood this trade reflects private material information. The absence of amendments, derivatives, or coordinated transfers suggests routine handling of equity compensation obligations.

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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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).

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^*

Gephart Brian

(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)
	CHIEF ACCOUNTING OFFICER

3. Date of Earliest Transaction (Month/Day/Year)
08/18/2025

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	08/18/2025		S(1)		2,961	D	$23.85	120,569	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. These shares were sold to cover the Reporting Person's tax obligation resulting from the settlement of vested Restricted Stock Units. The sale is mandated by the Issuer's election to require the satisfaction of tax withholding obligations to be funded by sell to cover transactions and does not represent a discretionary transaction by the Reporting Person.

	/s/ Aaron Saltz, attorney-in-fact	08/20/2025
	** 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 Magnite (MGNI) report on 08/18/2025?

The Form 4 reports a sale of 2,961 common shares at $23.85 per share executed to satisfy tax withholding from vested Restricted Stock Units.

Who filed the Form 4 for Magnite and what is their role?

The reporting person is Brian Gephart, Chief Accounting Officer of Magnite, Inc., and the form was signed by an attorney-in-fact.

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

After the sale, the reporting person beneficially owned 120,569 shares of Magnite common stock.

Was the sale discretionary or required?

The filing states the sale was mandated by the issuer's sell-to-cover election to satisfy tax withholding and was not a discretionary transaction by the reporting person.

Are there any derivative transactions reported in this Form 4?

No. The filing shows no derivative securities acquired, disposed of, or beneficially owned in Table II.