[Form 4] Magnite, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Magnite insider exercise and sales under 10b5-1 plan. Adam Lee Soroca, Chief Product Officer, exercised 24,986 vested employee stock options at a $4.92 exercise price on 09/02/2025 and immediately sold those shares in multiple transactions. He sold 9,269 shares at a weighted average price of $24.22 (range $23.74–$24.66) and 15,717 shares at a weighted average price of $24.97 (range $24.78–$25.05), executing the trades pursuant to a Rule 10b5-1 plan adopted May 28, 2025. After these transactions his beneficial ownership decreased from 371,379 to 346,393 shares. The options exercised were fully vested and the underlying shares were granted as compensation.

Positive

• Trades executed under a Rule 10b5-1 plan, indicating pre-arranged, compliant dispositions (plan adopted May 28, 2025).
• Exercised fully vested options (24,986) demonstrating alignment of compensation realization with plan terms.
• Transparent pricing disclosure with weighted-average sale prices and stated ranges; offer to provide per-price details on request.

Negative

• Beneficial ownership decreased by 24,986 shares, from 371,379 to 346,393, reflecting insider share reduction.
• Material portion of exercised shares were sold immediately, resulting in no increase to long-term insider-held shares from this exercise.

Insights

Financial Analyst

TL;DR: Routine option exercise and systematic sales under a 10b5-1 plan; modest insider dilution in holdings, not a clear signal of corporate change.

The reporting shows a standard exercise of fully vested employee options and contemporaneous sales executed under a pre-established Rule 10b5-1 trading plan. The transactions converted 24,986 options into shares and resulted in the sale of all 24,986 shares across two weighted-average price bands, reducing the reporting person’s holdings by 24,986 shares (from 371,379 to 346,393). For investors, this is a common liquidity action by an officer and is typically considered routine when performed under a 10b5-1 plan rather than ad hoc sales.

Corporate Governance Expert

TL;DR: Transactions comply with governance best practices by using a pre-existing 10b5-1 plan and documenting ranges for weighted-average sale prices.

The filing explicitly states the trades were made pursuant to a Rule 10b5-1 plan adopted May 28, 2025, which supports an affirmative defense to insider trading allegations. The filer discloses weighted-average sale prices and offers to provide per-price share counts on request, enhancing transparency. The options exercised were fully vested and granted as compensation, consistent with routine executive equity compensation realization. No other governance issues or unusual terms are disclosed in this Form 4.

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

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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).

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)
09/02/2025

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	09/02/2025		M(1)		24,986	A	$4.92	371,379	D
Common Stock	09/02/2025		S(1)		9,269	D	$24.22(2)	362,110	D
Common Stock	09/02/2025		S(1)		15,717	D	$24.97(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
Employee Stock Option (Right to Buy)	$4.92	09/02/2025		M(1)			24,986	(4)	02/20/2029	Common Stock	24,986	$0(5)	96,657	D

Explanation of Responses:

1. This exercise and subsequent sale were made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 28, 2025.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $23.74 to $24.66, 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.

3. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $24.78 to $25.05, 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.

4. The stock options have fully vested and are immediately exercisable.

5. Granted as compensation for services.

	/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.
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FAQ

What transactions did MGNI insider Adam Lee Soroca report on Form 4?

The filer exercised 24,986 employee stock options at a $4.92 exercise price on 09/02/2025 and sold those shares in multiple transactions under a 10b5-1 plan.

How did the sales break down and what were the prices?

He sold 9,269 shares at a weighted average price of $24.22 (range $23.74–$24.66) and 15,717 shares at a weighted average price of $24.97 (range $24.78–$25.05).

Did the filing indicate whether the options were vested?

Yes. The Form 4 states the stock options were fully vested and immediately exercisable.

Was the sale part of a pre-established trading plan?

Yes. The exercise and subsequent sales were executed pursuant to a Rule 10b5-1 trading plan adopted May 28, 2025.

How did these transactions affect Soroca’s beneficial ownership of MGNI?

Following the reported transactions, beneficial ownership decreased to 346,393 shares from 371,379 shares.