Magnite president sells 11K shares in plan trade

Rhea-AI Filing Summary

MAGNITE, INC. (MGNI) reported insider transactions by Sean Patrick Buckley, President, Revenue & Market Strategy. On August 18, 2026, he sold 2,759 shares of common stock at $25.00 per share, and on August 17, 2026, he sold 8,271 shares at a weighted average price of $24.31 per share. On August 15, 2026, 11,715 shares were disposed of to satisfy tax withholding obligations related to vesting of restricted stock units. The sales on August 17 and 18 were effected pursuant to a Rule 10b5-1 trading plan adopted on September 10, 2025.

Insider Trade Summary 10b5-1

Net Seller: 11,030 shares

Net Sell 3 txns

Insider Buckley Sean Patrick

Role See Remarks

Sold 11,030 shs ($270K)

Type	Security	Shares	Price	Value
Sale	Common Stock F2	2,759	$25.00	$69K
Sale	Common Stock F2, F3	8,271	$24.31	$201K
Tax Withholding	Common Stock F1	11,715	$24.73	$290K

Holdings After Transaction: Common Stock — 293,060 shares (Direct)

Footnotes (3)

1. F1. Represents the non-discretionary forfeiture of shares on behalf of the Reporting Person pursuant to an arrangement mandated by the Issuer to cover the tax withholding obligations associated with the vesting of restricted stock units.
2. F2. The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on September 10, 2025.
3. F3. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $24.05 to $24.55, 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 2026-08-18: 2,759 shares at $25.00 per share Shares sold 2026-08-17: 8,271 shares at $24.31 weighted average Shares disposed for tax withholding: 11,715 shares at $24.73 per share +2 more

5 metrics

Shares sold 2026-08-18 2,759 shares at $25.00 per share Open-market sale of MAGNITE, INC. common stock

Shares sold 2026-08-17 8,271 shares at $24.31 weighted average Open-market sale at prices from $24.05 to $24.55

Shares disposed for tax withholding 11,715 shares at $24.73 per share Non-discretionary forfeiture to cover RSU tax withholding

Net open-market shares sold 11,030 shares Net buy/sell shares across reported sale transactions

Rule 10b5-1 plan adoption date September 10, 2025 Plan governing the reported sale transactions

Key Terms

Rule 10b5-1 trading plan, restricted stock units, weighted average price, tax withholding obligations

4 terms

Rule 10b5-1 trading plan regulatory

"The reported transaction was effected pursuant to a Rule 10b5-1 trading plan"

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.

restricted stock units financial

"associated with the vesting of restricted stock units"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

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.

tax withholding obligations financial

"to cover the tax withholding obligations associated with the vesting"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transactions did MGNI executive Sean Patrick Buckley report?

Sean Patrick Buckley reported two open-market sales totaling 11,030 shares and a separate 11,715-share disposition for tax withholding related to vesting restricted stock units, all involving MAGNITE, INC. common stock.

At what prices did Sean Patrick Buckley sell MGNI shares?

He sold 2,759 shares at $25.00 per share on August 18, 2026, and 8,271 shares at a weighted average of $24.31 per share on August 17, 2026, with actual sale prices ranging from $24.05 to $24.55.

How many MGNI shares were used to cover Sean Patrick Buckley’s tax withholding?

A total of 11,715 shares of MAGNITE, INC. common stock were forfeited on August 15, 2026 to satisfy tax withholding obligations arising from the vesting of restricted stock units.

Were Sean Patrick Buckley’s MGNI stock sales under a Rule 10b5-1 plan?

Yes. The filing states the reported sales were made pursuant to a Rule 10b5-1 trading plan adopted by Sean Patrick Buckley on September 10, 2025, indicating they were pre-arranged under that plan.

What is the net effect of Sean Patrick Buckley’s recent MGNI trades?

The Form 4 shows 11,030 shares sold in open-market transactions and 11,715 shares disposed to cover tax withholding. Overall, the insider activity reflects a net sell position over these reported transactions.

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

Form 4 Insider Transactions: What Each Field Means →

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Accepted by SEC EDGAR 08/18/2026 - 04:14 PM EDT Learn about SEC filing dates

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)
08/15/2026

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	08/15/2026		F(1)		11,715	D	$24.73	304,090	D
Common Stock	08/17/2026		S(2)		8,271	D	$24.31(3)	295,819	D
Common Stock	08/18/2026		S(2)		2,759	D	$25	293,060	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. Represents the non-discretionary forfeiture of shares on behalf of the Reporting Person pursuant to an arrangement mandated by the Issuer to cover the tax withholding obligations associated with the vesting of restricted stock units.

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

3. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $24.05 to $24.55, 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	08/18/2026
	** 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)