[Form 4] Magnite, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Adam Lee Soroca, Chief Product Officer of Magnite, Inc. (MGNI), reported two non-discretionary sales of company common stock on 08/18/2025 and 08/19/2025. On 08/18/2025 he sold 9,700 shares at $23.85 per share to satisfy tax withholding from vested restricted stock units. On 08/19/2025 he sold 10,579 shares at a weighted average price of $23.47 pursuant to a Rule 10b5-1 trading plan adopted on March 7, 2025. The filings show beneficial ownership of 356,972 shares after the 08/18 sale and 346,393 shares after the 08/19 sale. The Form 4 was signed via attorney-in-fact on 08/20/2025.

Positive

• Sales executed under a Rule 10b5-1 trading plan (adopted March 7, 2025), providing an affirmative defense for insider trading concerns
• Sell-to-cover transaction for RSU tax withholding clarifies the non-discretionary nature of part of the sales
• Filing includes weighted average price range disclosure for the 08/19 sales and offers to provide per-price details on request

Negative

• Aggregate insider holdings decreased by 20,279 shares following the two reported sales
• Form 4 does not state percentage ownership or company market cap, so relative materiality of the sales cannot be determined from this filing alone

Insights

Corporate Governance Expert

TL;DR: Insider sales were routine, largely non-discretionary, and executed under a pre-established 10b5-1 plan, indicating compliance with insider trading controls.

The transactions disclose standard sell-to-cover activity for vested RSUs and additional sales under a Rule 10b5-1 plan adopted March 7, 2025. Such mechanisms typically reduce governance concerns because the sales were either mandated for tax withholding or followed an established trading plan that provides an affirmative defense against insider trading allegations. The filings are concise and provide the weighted average price range for the 08/19 sales, with an undertaking to disclose per-price details on request. No material corporate governance red flags are apparent from the Form 4 alone.

Securities Analyst

TL;DR: Insider sold 20,279 shares across two days at ~ $23.5 average; reductions are modest relative to total reported holdings but represent a clear decrease in insider stake.

The reports show sales of 9,700 shares at $23.85 and 10,579 shares at a weighted average of $23.47, totaling 20,279 shares. Post-transaction beneficial ownership is reported as 346,393 shares after the second sale. While the absolute share reduction is transparent, the Form 4 does not provide company market capitalization or percentage change in ownership, so the investor impact cannot be fully assessed from this filing alone. Transactions appear properly documented and executed under permitted procedures.

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^*

Soroca Adam Lee

(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 PRODUCT 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)		9,700	D	$23.85	356,972	D
Common Stock	08/19/2025		S(2)		10,579	D	$23.47(3)	346,393	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.

2. The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on March 7, 2025.

3. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $23.18 to $24.10, 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	08/20/2025
	** 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 Magnite (MGNI) insider Adam Lee Soroca sell and when?

The Form 4 reports sales of 9,700 shares on 08/18/2025 and 10,579 shares on 08/19/2025.

Why were the shares sold by Adam Lee Soroca?

The 08/18/2025 sale was to cover tax withholding for vested RSUs. The 08/19/2025 sale was executed under a Rule 10b5-1 trading plan adopted March 7, 2025.

At what prices were the shares sold?

The 08/18 sale reported a price of $23.85. The 08/19 sale reported a weighted average price of $23.47 with individual trades ranging from $23.18 to $24.10.

How many shares did Soroca beneficially own after the transactions?

The filing reports 356,972 shares after the 08/18 sale and 346,393 shares after the 08/19 sale.

Who signed the Form 4 and when?

The Form 4 was signed by Aaron Saltz, attorney-in-fact on 08/20/2025.