Magnite (MGNI) officer sells 19,233 shares in $21 Rule 10b5-1 trade

Rhea-AI Filing Summary

MAGNITE, INC. officer Sean Patrick Buckley reported an open-market sale of 19,233 shares of common stock on July 7, 2026. The shares were sold at a weighted average price of $21.03 per share, in multiple trades between $21.00 and $21.16.

After this transaction, Buckley directly holds 354,281 shares of Magnite common stock. The sale was carried out under a pre-arranged Rule 10b5-1 trading plan that Buckley adopted on September 10, 2025, indicating the trades were scheduled in advance.

Insider Trade Summary 10b5-1

Net Seller: 19,233 shares ($404,470)

Net Sell 1 txn

Insider Buckley Sean Patrick

Role See Remarks

Sold 19,233 shs ($404K)

Type	Security	Shares	Price	Value
Sale	Common Stock	19,233	$21.03	$404K

Holdings After Transaction: Common Stock — 354,281 shares (Direct, null)

Footnotes (1)

1. The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on September 10, 2025. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $21.00 to $21.16, 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.

Key Figures

Shares sold: 19,233 shares Weighted average sale price: $21.03 per share Post-transaction holdings: 354,281 shares +2 more

5 metrics

Shares sold 19,233 shares Open-market sale on July 7, 2026

Weighted average sale price $21.03 per share Common stock sale in multiple trades

Post-transaction holdings 354,281 shares Direct ownership after sale

Trade price range $21.00–$21.16 per share Prices of individual sale transactions

10b5-1 plan adoption date September 10, 2025 Governing pre-arranged trading plan

Key Terms

Rule 10b5-1 trading plan, weighted average price, open-market sale, Form 4

4 terms

Rule 10b5-1 trading plan regulatory

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

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

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 sale financial

"transaction_action: open-market sale"

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

Form 4 regulatory

"within the range set forth in this footnote to this Form 4."

Form 4 is a official document that company insiders, such as executives or major shareholders, file with regulators whenever they buy or sell company shares. It provides transparency about how those with inside knowledge are trading, helping investors see if insiders are confident in the company's prospects or may be selling for personal reasons. This information can influence investor decisions by revealing insiders' perspectives on the company's value.

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Available on EDGAR 07/09/2026 - 04:28 PM Accepted by SEC EDGAR 07/09/2026 - 04:27 PM Learn about SEC filing dates

FAQ

What insider transaction did MAGNITE (MGNI) report for Sean Patrick Buckley?

MAGNITE officer Sean Patrick Buckley sold 19,233 shares of common stock in an open-market transaction. The sale occurred on July 7, 2026, and was reported on Form 4 as a routine insider transaction with full share and price details disclosed.

At what price did Sean Patrick Buckley sell MAGNITE (MGNI) shares?

Buckley’s reported sale used a weighted average price of $21.03 per share. The shares were actually sold in multiple trades at prices ranging from $21.00 to $21.16, with the company offering to provide full breakdowns upon request.

How many MAGNITE (MGNI) shares does Sean Patrick Buckley own after this sale?

Following the July 7, 2026 transaction, Buckley directly holds 354,281 MAGNITE common shares. This post-transaction figure, reported in the Form 4, helps investors gauge the scale of the sale relative to his remaining ownership stake.

Was the MAGNITE (MGNI) insider sale made under a Rule 10b5-1 plan?

Yes. The Form 4 states the transaction was effected under a Rule 10b5-1 trading plan adopted on September 10, 2025. Such pre-arranged plans schedule trades in advance, reducing the significance of short-term market timing decisions.

What does a weighted average price mean in the MAGNITE (MGNI) Form 4 filing?

The weighted average price of $21.03 represents the average sale price across multiple trades. Individual transactions occurred between $21.00 and $21.16 per share, and the reporting person offered to provide detailed trade-by-trade data upon request.

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^*

Buckley Sean Patrick

(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)
	See Remarks

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
07/07/2026

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	07/07/2026		S(1)		19,233	D	$21.03(2)	354,281	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 transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on September 10, 2025.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $21.00 to $21.16, 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.

Remarks:

President, Revenue & Market Strategy

	/s/ Aaron Saltz, attorney-in-fact	07/09/2026
	** 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)