[Form 4] Magnite, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Magnite (NASDAQ: MGNI) filed a Form 4 showing CEO Michael G. Barrett sold 300,000 shares of common stock on 06/24/2025 at a weighted-average price of $20.01, realizing roughly $6.0 million.

The sale was executed under a Rule 10b5-1 plan adopted 03/12/2025. Barrett’s direct holdings fell from 656,708 to 356,708 shares, a reduction of about 46%.

No derivative trades were reported. While pre-scheduled, the magnitude of the disposition is material and could affect perceptions of insider confidence.

Positive

• None.

Negative

• CEO sold 300,000 shares (~$6.0 million), a materially large insider sale.
• Barrett’s direct stake cut by ~46%, potentially signaling lowered insider confidence.

Insights

Corporate Governance Analyst

TL;DR: CEO sells 46% of stake; optics lean negative despite plan.

The Form 4 confirms a sizeable, pre-planned disposal: 300 k shares (~$6 M). Because the CEO relinquished nearly half of his direct ownership, governance observers may question long-term commitment. The 10b5-1 framework mitigates timing concerns, yet the absolute scale remains meaningful. With no offsetting option exercise or share purchase, the action reduces economic alignment and can pressure sentiment if followed by further insider selling or lack of bullish signals.

Portfolio Manager

TL;DR: Large insider sale adds supply; monitor for follow-through pressure.

Barrett’s $6 M cash-out introduces a notable supply of MGNI stock. Proceeds dwarf routine diversification moves, indicating a conscious stake reduction rather than tax optimisation. Although executed via a 10b5-1 plan, the market often focuses on size, not motive. With 356,708 shares left, exposure remains but is materially lighter. Absent concurrent insider buying or strong corporate catalysts, the trade skews near-term sentiment negative and may influence liquidity dynamics.

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^*

BARRETT MICHAEL G.

(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)

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	CEO

3. Date of Earliest Transaction (Month/Day/Year)
06/24/2025

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	06/24/2025		S(1)		300,000	D	$20.01(2)	356,708	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 transactions were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on March 12, 2025.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $20.00 to $20.0532, 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.

	/s/ Aaron Saltz, attorney-in-fact	06/26/2025
	** 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

How many MGNI shares did the CEO sell on June 24, 2025?

Michael Barrett disposed of 300,000 shares according to the Form 4.

What was the average selling price for the CEO’s MGNI shares?

The weighted-average price was approximately $20.01 per share.

How many MGNI shares does the CEO still own after the transaction?

Barrett retains 356,708 shares of Magnite common stock.

Was the insider sale executed under a 10b5-1 plan?

Yes. The sale was made under a Rule 10b5-1 trading plan adopted on March 12, 2025.

What percentage of his holdings did the CEO sell?

The sale represented roughly 46% of his directly held shares prior to the transaction.

How much cash did the CEO realize from selling MGNI shares?

Gross proceeds were about $6.0 million (300,000 shares × $20.01).