Magnite director reports 7,500-share sale under 10b5-1 plan

Rhea-AI Filing Summary

Paul Caine, a director of Magnite, Inc. (MGNI), reported a sale of common stock under a pre-established Rule 10b5-1 plan. On 09/19/2025 the reporting person sold 7,500 shares at $25 per share, reducing his beneficial ownership to 158,603 shares. The filing indicates the trades were executed pursuant to a 10b5-1 trading plan adopted on August 15, 2024, and the Form 4 was signed by an attorney-in-fact on behalf of the reporting person.

Insights

Securities Analyst

TL;DR: Director sold a modest block of shares under a pre-set 10b5-1 plan; filing is routine and not immediately material.

The transaction shows a director-level insider executing a planned sale: 7,500 shares sold at $25 reducing holdings to 158,603. Because the sale was made under a documented 10b5-1 plan adopted in August 2024, it represents a scheduled disposition rather than an opportunistic trade. The size of the sale relative to post-transaction holdings appears limited, and the filing contains no other transactions, derivative activity, or disclosures suggesting material corporate events.

Corporate Governance Expert

TL;DR: Compliance procedure followed; 10b5-1 plan adoption and Form 4 signature by attorney-in-fact indicate formal process.

The Form 4 documents adherence to insider-trading compliance via a Rule 10b5-1 plan adopted 08/15/2024. The signature by an attorney-in-fact is properly executed. There are no indications of amendments, derivative transactions, or changes in relationship status. From a governance perspective, the disclosure meets Section 16 requirements and provides transparency about the director's scheduled sale.

Insider Trade Summary

Net Seller: 7,500 shares ($187,500)

Net Sell 1 txn

Insider Caine Paul

Role Director

Sold 7,500 shs ($188K)

Type	Security	Shares	Price	Value
Sale	Common Stock	7,500	$25.00	$188K

Holdings After Transaction: Common Stock — 158,603 shares (Direct)

Footnotes (1)

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Form 4 Insider Transactions: What Each Field Means →

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^*

Caine Paul

(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
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
09/19/2025

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	09/19/2025		S(1)		7,500	D	$25	158,603	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 sales were made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 15, 2024.

	/s/ Aaron Saltz, attorney-in-fact	09/19/2025
	** 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 insider transaction did Paul Caine report for MGNI?

The Form 4 reports a sale of 7,500 common shares on 09/19/2025 at a price of $25 per share.

How many Magnite (MGNI) shares does the reporting person own after the sale?

Following the reported transaction the reporting person beneficially owned 158,603 shares.

Was the sale made under a trading plan for MGNI insider?

Yes, the sale was made pursuant to a Rule 10b5-1 trading plan that the reporting person adopted on 08/15/2024.

Who signed the Form 4 for the reporting person?

The Form 4 was signed by Aaron Saltz, attorney-in-fact, on 09/19/2025.

Does the Form 4 show any option or derivative transactions for MGNI?

No. Table II lists no derivative securities; only a non-derivative sale of common stock is reported.