Magnite (NASDAQ: MGNI) CTO vests PSUs, sells shares for taxes owed

Rhea-AI Filing Summary

Magnite, Inc. chief technology officer David Buonasera reported the vesting of performance-based equity and related share withholding for taxes. On January 9, 2026, 22,935 performance stock units 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.

Based on the company’s total stockholder return over a three-year period relative to the Russell 2000 index, the compensation committee determined achievement of 126.35%, resulting in the 22,935 vested shares. On the same date, 12,330 shares were non-discretionarily forfeited to cover tax withholding obligations at $16.17 per share. After these transactions, Buonasera directly beneficially owned 319,232 shares of 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

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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^*

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) report for its CTO?

Magnite (MGNI) reported that chief technology officer David Buonasera had 22,935 performance stock units convert into the same number of shares of common stock on January 9, 2026, followed by a tax-related share forfeiture.

How many Magnite (MGNI) shares did the CTO forfeit for taxes?

The filing shows that 12,330 shares of Magnite common stock were non-discretionarily forfeited on behalf of the CTO to cover tax withholding obligations at a price of $16.17 per share.

How many Magnite (MGNI) shares does the CTO own after these transactions?

After the reported equity vesting and tax withholding forfeiture, David Buonasera beneficially owned 319,232 shares of Magnite common stock directly.

What performance condition governed the CTO’s Magnite (MGNI) PSUs?

The performance stock units vested based on Magnite’s total stockholder return for the three-year period beginning January 1, 2023 relative to companies in the Russell 2000 index, with the award eligible to vest from 0% to 150% of target.

What was the final performance outcome for the Magnite (MGNI) PSU award?

The compensation committee determined 126.35% achievement of the performance goals, resulting in the CTO actually vesting 22,935 shares of Magnite common stock from the PSU award.

Under which plan were the Magnite (MGNI) PSUs granted to the CTO?

The performance stock units were granted as an equity grant under Magnite’s Amended and Restated 2014 Equity Incentive Plan, as noted in the footnotes.