Magnite (MGNI) CTO vests 22,935 PSUs, with tax withholding shares

Rhea-AI Filing Summary

Magnite, Inc. reported an equity vesting event for its Chief Technology Officer, David Buonasera. On January 9, 2026, 22,935 performance stock units (PSUs) granted under the company’s Amended and Restated 2014 Equity Incentive Plan converted into the same number of common shares at an exercise price of $0.

The PSUs vested based on Magnite’s total stockholder return over a three-year period starting January 1, 2023, compared with companies in the Russell 2000 index. The award could vest from 0% to 150% of the target amount, and the compensation committee determined achievement of 126.35%, resulting in 22,935 shares vesting.

To cover tax withholding obligations tied to this vesting, 12,330 shares of common stock were automatically forfeited at a price of $16.17 per share. After these transactions, Buonasera directly held 319,232 shares of Magnite common stock.

Insider Trade Summary

22,935 shares exercised/converted

Mixed 3 txns

Insider Buonasera David

Role CHIEF TECHNOLOGY OFFICER

Type	Security	Shares	Price	Value
Exercise	Performance Stock Units	22,935	$0.00	--
Exercise	Common Stock	22,935	$0.00	--
Tax Withholding	Common Stock	12,330	$16.17	$199K

Holdings After Transaction: Performance Stock Units — 0 shares (Direct); Common Stock — 331,562 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 March 2, 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 22,935 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

OMB Number:			3235-0287
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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^*

Buonasera David

(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)
	CHIEF TECHNOLOGY OFFICER

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		22,935	A	$0(1)	331,562	D
Common Stock	01/09/2026		F(2)		12,330	D	$16.17	319,232	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			22,935	(4)	(4)	Common Stock	22,935	$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 March 2, 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 22,935 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.
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FAQ

What insider transaction did Magnite (MGNI) disclose in this Form 4?

The filing reports that Chief Technology Officer David Buonasera had 22,935 performance stock units convert into the same number of shares of Magnite common stock on January 9, 2026, followed by an automatic share withholding to cover taxes.

How many Magnite performance stock units vested for the CTO and on what basis?

A total of 22,935 PSUs vested for the CTO. The vesting was based on Magnite’s total stockholder return over the three-year period beginning January 1, 2023 versus companies in the Russell 2000 index, with the award paying out at 126.35% of target.

How were Magnite (MGNI) shares withheld for taxes in this insider transaction?

The filing states that 12,330 shares of Magnite common stock were non-discretionarily forfeited at $16.17 per share under an arrangement mandated by the company to satisfy tax withholding obligations related to the PSU vesting.

What is a performance stock unit (PSU) in the context of Magnite’s equity plan?

Each Magnite PSU represents a contingent right to receive, upon vesting, one share of the company’s common stock, with vesting dependent on issuer performance criteria described in the award’s terms.

What performance range could the Magnite PSU award vest at and what was the outcome?

The PSU award could vest from 0% to 150% of the target number of units. The compensation committee determined performance at 126.35%, leading to an actual vesting of 22,935 shares for the CTO.

How many Magnite shares does the CTO own after the reported Form 4 transactions?

After the PSU conversion and tax withholding forfeiture, Chief Technology Officer David Buonasera directly held 319,232 shares of Magnite common stock.