Magnite (MGNI) CFO forfeits shares to cover RSU tax bill

Rhea-AI Filing Summary

MAGNITE, INC. (MGNI) reported an insider equity-related transaction by its Chief Financial Officer, David Day. On 2026-08-15, 14,170 shares of common stock were forfeited at $24.73 per share to satisfy tax withholding obligations tied to the vesting of restricted stock units, under a non-discretionary arrangement mandated by the company. After this tax-withholding disposition, Day directly holds 452,861 shares of MAGNITE common stock.

Insider Trade Summary

Net Seller: 14,170 shares

Net Sell 1 txn

Insider Day David

Role CHIEF FINANCIAL OFFICER

Type	Security	Shares	Price	Value
Tax Withholding	Common Stock F1	14,170	$24.73	$350K

Holdings After Transaction: Common Stock — 452,861 shares (Direct)

Footnotes (1)

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.

Key Figures

Shares forfeited for tax withholding: 14,170 shares Per-share value for forfeited shares: $24.73 per share Shares owned after transaction: 452,861 shares

3 metrics

Shares forfeited for tax withholding 14,170 shares Non-discretionary forfeiture to cover RSU-related tax withholding on 2026-08-15

Per-share value for forfeited shares $24.73 per share Value applied to the 14,170 shares forfeited for tax withholding

Shares owned after transaction 452,861 shares Direct MAGNITE common stock holdings of CFO David Day after the tax-withholding disposition

Key Terms

restricted stock units, non-discretionary forfeiture, tax withholding obligations

3 terms

restricted stock units financial

"tax withholding obligations 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.

non-discretionary forfeiture financial

"Represents the non-discretionary forfeiture of shares on behalf of the Reporting Person"

tax withholding obligations financial

"to cover the tax withholding obligations associated with the vesting of restricted stock units"

FAQ

What insider transaction did MGNI’s CFO David Day report on this Form 4?

David Day reported a tax-withholding disposition of 14,170 MAGNITE (MGNI) shares. The shares were forfeited to cover tax obligations arising from the vesting of restricted stock units under a company-mandated arrangement.

Was the MGNI CFO’s Form 4 transaction an open-market sale of shares?

No, the transaction was not an open-market sale. It was a non-discretionary forfeiture of shares mandated by MAGNITE to cover tax withholding obligations associated with vesting restricted stock units.

How many MAGNITE (MGNI) shares were used for tax withholding by the CFO?

A total of 14,170 MAGNITE common shares were forfeited. These shares were withheld to satisfy tax withholding obligations linked to the vesting of the CFO’s restricted stock units.

What price per share is associated with the MGNI CFO’s tax-withholding transaction?

The tax-withholding disposition used a reference price of $24.73 per MAGNITE share. This per-share value is reported for the shares forfeited to satisfy the CFO’s RSU-related tax obligations.

How many MAGNITE (MGNI) shares does the CFO own after this Form 4 transaction?

Following the transaction, David Day directly owns 452,861 MAGNITE common shares. This figure reflects his post-withholding share position after forfeiting 14,170 shares for tax obligations tied to RSU vesting.

What triggered the MAGNITE CFO’s share forfeiture reported on this Form 4?

The forfeiture was triggered by the vesting of restricted stock units. MAGNITE mandated a non-discretionary share forfeiture to cover tax withholding obligations arising from that RSU vesting event.

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

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 08/18/2026 - 04:18 PM Accepted by SEC EDGAR 08/18/2026 - 04:17 PM 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).

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^*

Day David

(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)
	CHIEF FINANCIAL OFFICER

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)		14,170	D	$24.73	452,861	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.

Remarks:

	/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)