[Form 4] Magnite, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Magnite, Inc. (MGNI) officer sale disclosed on Form 4. Chief Technology Officer David Buonasera reported a sale of 2,950 shares of Magnite common stock on 09/03/2025 at a price of $25.37 per share, leaving him with 238,629 shares beneficially owned following the transaction. The filing states the sale was executed pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on August 15, 2024. The form was signed by attorney-in-fact Aaron Saltz on 09/04/2025.

Positive

• Transaction executed under a Rule 10b5-1 plan, indicating pre-arranged, compliant insider trading
• Timely reporting with Form 4 filed and signed by attorney-in-fact on 09/04/2025
• Significant retained ownership: 238,629 shares remain beneficially owned after the sale

Negative

• Insider sale of 2,950 shares increases available float by that amount
• Sale price $25.37 may be perceived by some investors as cashing out part of holdings

Insights

Financial Analyst

Routine insider sale under a pre-established 10b5-1 plan; limited immediate informational impact.

The Form 4 documents a single non-derivative sale of 2,950 shares at $25.37, executed under a 10b5-1 plan adopted 08/15/2024. The post-transaction beneficial ownership remains at 238,629 shares, indicating continued meaningful holdings. As this was a planned disposition rather than an ad-hoc sale, it provides limited new insight into executive views on near-term company fundamentals, though it does increase free float by the disclosed amount.

Corporate Governance Expert

Disclosed trade follows an established trading plan and was properly reported, reflecting governance-compliant insider activity.

The filing indicates compliance with Rule 10b5-1 by documenting the plan adoption date and reporting the transaction promptly on Form 4. The signature by an attorney-in-fact with a filing date of 09/04/2025 further indicates procedural adherence. The transaction does not show any derivative activity or amendments; it appears to be a standard, pre-planned equity disposition by an executive.

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
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^*

Buonasera David

(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 TECHNOLOGY OFFICER

3. Date of Earliest Transaction (Month/Day/Year)
09/03/2025

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	09/03/2025		S(1)		2,950	D	$25.37	238,629	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 reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 15, 2024.

	/s/ Aaron Saltz, attorney-in-fact	09/04/2025
	** 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 Magnite (MGNI) CTO David Buonasera sell and when?

The filing reports a sale of 2,950 shares on 09/03/2025 at $25.37 per share.

How many Magnite shares does David Buonasera own after the transaction?

He beneficially owns 238,629 shares following the reported sale.

Was the sale part of an approved trading plan?

Yes. The sale was effected pursuant to a Rule 10b5-1 trading plan adopted on 08/15/2024.

Who signed the Form 4 for Magnite and when was it signed?

The Form 4 was signed by Aaron Saltz, attorney-in-fact, on 09/04/2025.

Did the Form 4 disclose any options or derivative transactions?

No. Table II for derivative securities shows no reported derivative transactions in this filing.