Magnite (MGNI) Chief Accounting Officer sells 12,479 company shares

Rhea-AI Filing Summary

Magnite, Inc. officer Brian Gephart, the Chief Accounting Officer, reported a sale of common stock. On 2026-08-10, he sold 12,479 shares of Magnite common stock in an open market or private transaction at a weighted average price of $24.68 per share, with actual prices ranging from $24.68 to $24.71. Following this transaction, he directly holds 106,117 shares of Magnite common stock.

Insider Trade Summary

Net Seller: 12,479 shares

Net Sell 1 txn

Insider Gephart Brian

Role CHIEF ACCOUNTING OFFICER

Sold 12,479 shs ($308K)

Type	Security	Shares	Price	Value
Sale	Common Stock F1	12,479	$24.68	$308K

Holdings After Transaction: Common Stock — 106,117 shares (Direct)

Footnotes (1)

1. F1. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $24.68 to $24.71, 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.

Key Figures

Shares sold: 12,479 shares Weighted average sale price: $24.68 per share Price range: $24.68–$24.71 per share +3 more

6 metrics

Shares sold 12,479 shares Non-derivative common stock sale on 2026-08-10

Weighted average sale price $24.68 per share Multiple transactions, prices from $24.68 to $24.71

Price range $24.68–$24.71 per share Range of prices for the 2026-08-10 sale trades

Shares owned after transaction 106,117 shares Directly held Magnite common stock following the sale

Net buy/sell shares 12,479 shares net sold Net effect across all reported transactions in this filing

Sell transactions count 1 sale Single non-derivative sale transaction reported

Key Terms

weighted average price, open market or private transaction, non-derivative

3 terms

weighted average price financial

"The price reported in Column 4 is a weighted average price."

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

open market or private transaction financial

"Sale in open market or private transaction"

non-derivative financial

"transaction_type: "non-derivative" for the common stock sale"

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 08/12/2026 - 04:55 PM Accepted by SEC EDGAR 08/12/2026 - 04:54 PM Learn about SEC filing dates

FAQ

What did Magnite (MGNI) officer Brian Gephart report in this Form 4?

Brian Gephart reported a sale of 12,479 shares of Magnite common stock on 2026-08-10 in an open market or private transaction at a weighted average price of $24.68 per share.

At what price did Brian Gephart sell Magnite (MGNI) shares?

The reported price is a weighted average of $24.68 per share. According to the disclosure, the shares were sold in multiple trades at prices ranging from $24.68 to $24.71, inclusive.

How many Magnite (MGNI) shares does Brian Gephart hold after this sale?

After the reported sale, Brian Gephart directly holds 106,117 shares of Magnite common stock. This figure reflects his post-transaction ownership as stated in the filing’s ownership table.

What is the transaction type reported by Brian Gephart in Magnite (MGNI)?

The transaction is coded as “S”, described as a sale in open market or private transaction. It involves non-derivative Magnite common stock and is classified as a sell transaction in the filing data.

Was Brian Gephart’s Magnite (MGNI) trade under a Rule 10b5-1 plan?

The filing indicates the Rule 10b5-1 checkbox is not affirmed (set to false). No footnote states that the 12,479-share sale on 2026-08-10 was executed pursuant to a Rule 10b5-1 trading plan.

What role does Brian Gephart hold at Magnite (MGNI) in this Form 4?

Brian Gephart is identified as an officer of Magnite with the title Chief Accounting Officer. The reported 12,479-share sale involves his directly held Magnite common stock.

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).

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^*

Gephart Brian

(Last) (First) (Middle)

C/O MAGNITE, INC.

1250 BROADWAY, 9TH FLOOR

(Street)

NEW YORK NEW YORK 10001

(City) (State) (Zip)

UNITED STATES

(Country)

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 ACCOUNTING OFFICER

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
08/10/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

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	08/10/2026		S		12,479	D	$24.68(1)	106,117	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 price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $24.68 to $24.71, 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.

Remarks:

	/s/ Aaron Saltz, attorney-in-fact	08/12/2026
	** 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.
* Form 4: SEC 1474 (03-26)