Magnite (MGNI) president vests 64,125 shares, with tax sale to cover taxes

Rhea-AI Filing Summary

Magnite, Inc. executive Sean Patrick Buckley, President, Revenue, reported the vesting of performance-based equity and related tax share withholding. On January 9, 2026, 64,125 performance stock units were converted into an equal number of shares of Magnite common stock at an exercise price of $0 under the company’s Amended and Restated 2014 Equity Incentive Plan. The award’s vesting was based on Magnite’s total stockholder return over a three-year period starting January 1, 2023, relative to Russell 2000 companies, with achievement determined at 126.35%, resulting in the 64,125 vested shares. To cover tax withholding tied to this vesting, 30,369 shares of common stock were forfeited at a price of $16.17 per share. Following these transactions, Buckley directly holds 429,941 shares of Magnite common stock.

Insider Trade Summary

64,125 shares exercised/converted

Mixed 3 txns

Insider Buckley Sean Patrick

Role President, Revenue

Type	Security	Shares	Price	Value
Exercise	Performance Stock Units	64,125	$0.00	--
Exercise	Common Stock	64,125	$0.00	--
Tax Withholding	Common Stock	30,369	$16.17	$491K

Holdings After Transaction: Performance Stock Units — 0 shares (Direct); Common Stock — 460,310 shares (Direct)

Footnotes (1)

1. Equity grant under the Company's Amended and Restated 2014 Equity Incentive Plan. 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 the performance stock units ("PSUs") being reported herein. Each PSU represents a contingent right to receive, on vesting, one share of the Issuer's common stock, subject to Issuer performance as more specifically described in Footnote 4 herein. Vesting of the PSU was determined based on the Issuer's total stockholder return ("TSR") for the three-year period beginning on January 1, 2023 relative to the TSRs of the companies in the Russell 2000 index over that period. The number of PSUs reported in column 5 on the Form 4 filed with the Securities and Exchange Commission on January 4, 2023 reflected the target number of PSUs initially subject to the award. The award was eligible to vest as to 0% to 150% of the target number of PSUs. On January 9, 2026, the Compensation Committee of the Issuer's Board of Directors determined that, based on 126.35% achievement, the Reporting Person actually vested 64,125 shares.

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

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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^*

Buckley Sean Patrick

(Last) (First) (Middle)

C/O MAGNITE, INC.

1250 BROADWAY, 9TH 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)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	President, Revenue

3. Date of Earliest Transaction (Month/Day/Year)
01/09/2026

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	01/09/2026		M		64,125	A	$0(1)	460,310	D
Common Stock	01/09/2026		F(2)		30,369	D	$16.17	429,941	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
Performance Stock Units	(3)	01/09/2026		M			64,125	(4)	(4)	Common Stock	64,125	$0(1)	0	D

Explanation of Responses:

1. Equity grant under the Company's Amended and Restated 2014 Equity Incentive Plan.

2. 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 the performance stock units ("PSUs") being reported herein.

3. Each PSU represents a contingent right to receive, on vesting, one share of the Issuer's common stock, subject to Issuer performance as more specifically described in Footnote 4 herein.

4. Vesting of the PSU was determined based on the Issuer's total stockholder return ("TSR") for the three-year period beginning on January 1, 2023 relative to the TSRs of the companies in the Russell 2000 index over that period. The number of PSUs reported in column 5 on the Form 4 filed with the Securities and Exchange Commission on January 4, 2023 reflected the target number of PSUs initially subject to the award. The award was eligible to vest as to 0% to 150% of the target number of PSUs. On January 9, 2026, the Compensation Committee of the Issuer's Board of Directors determined that, based on 126.35% achievement, the Reporting Person actually vested 64,125 shares.

	/s/ Aaron Saltz, attorney-in-fact	01/12/2026
	** 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).
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FAQ

What insider transactions did MGNI’s President, Revenue report on this Form 4?

The filing shows that Sean Patrick Buckley, Magnite’s President, Revenue, had 64,125 performance stock units convert into the same number of common shares on January 9, 2026, and then 30,369 common shares were forfeited to cover tax withholding.

How many Magnite (MGNI) performance stock units vested for Sean Patrick Buckley?

Based on the company’s disclosed performance criteria, 64,125 performance stock units vested for Sean Patrick Buckley, resulting in the issuance of 64,125 shares of Magnite common stock at an exercise price of $0 per share.

What performance criteria governed the MGNI performance stock units that vested?

The vesting was tied to Magnite’s total stockholder return over the three-year period beginning January 1, 2023, measured against companies in the Russell 2000 index. The award could vest from 0% to 150% of target, and the Compensation Committee determined 126.35% achievement, leading to 64,125 shares vesting.

Why were 30,369 Magnite (MGNI) shares forfeited in this Form 4?

The 30,369 common shares were a non-discretionary forfeiture mandated by Magnite to satisfy tax withholding obligations related to the vesting of the performance stock units, at a price of $16.17 per share, as described in the footnotes.

How many Magnite (MGNI) shares does Sean Patrick Buckley own after these transactions?

After the PSU vesting and tax-related forfeiture reported on January 9, 2026, Sean Patrick Buckley directly holds 429,941 shares of Magnite common stock.

Were any derivative securities remaining after the MGNI performance stock units vested?

No derivative balance remained from this award after vesting; the entry for the performance stock units in the derivative table shows 0 derivative securities beneficially owned following the reported transaction.