Magnite executive sells 20,000 shares after option exercise

Magnite, Inc. executive Katie Seitz Evans, President, Product & Operations, exercised employee stock options for 20,000 shares of common stock at an exercise price of $5.1600 per share on August 6, 2026, then sold 20,000 shares at $24.0000 per share.

Rhea-AI Filing Summary

Magnite, Inc. executive Katie Seitz Evans, President, Product & Operations, exercised employee stock options for 20,000 shares of common stock at an exercise price of $5.1600 per share on August 6, 2026, then sold 20,000 shares at $24.0000 per share. The options were fully vested, granted as compensation, and the exercise and sale were made under a Rule 10b5-1 trading plan adopted on August 28, 2025.

Insider Trade Summary 10b5-1

Exercise and Sale: 20,000 shares ($377K approx. pre-tax spread)

Exercise and Sale 3 txns

Insider Evans Katie Seitz

Role See Remarks

Sold 20,000 shs ($480K)

Approx. gross sale proceeds $480K

Approx. exercise cost $103K

Approx. pre-tax spread $377K

Type	Security	Shares	Price	Value
Exercise	Employee Stock Option (Right to Buy) F1, F3, F2	20,000	$0.00	$0.00
Exercise	Common Stock F1	20,000	$5.16	$103K
Sale	Common Stock F1	20,000	$24.00	$480K

Holdings After Transaction: Employee Stock Option (Right to Buy) — 0 contracts (Direct); Common Stock — 496,840 shares (Direct)

Footnotes (3)

1. F1. This exercise and subsequent sale were made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 28, 2025.
2. F2. The stock options have fully vested and are immediately exercisable.
3. F3. Granted as compensation for services.

Key Figures

Options exercised: 20,000 shares Option exercise price: $5.1600 per share Common shares acquired: 20,000 shares +4 more

7 metrics

Options exercised 20,000 shares Employee Stock Option (Right to Buy) exercised on August 6, 2026

Option exercise price $5.1600 per share Exercise price of employee stock option

Common shares acquired 20,000 shares Common stock received from option exercise on August 6, 2026

Common shares sold 20,000 shares Common stock sold on August 6, 2026

Sale price $24.0000 per share Price per share for Magnite common stock sale

Option expiration date February 27, 2029 Expiration date of the exercised employee stock options

10b5-1 plan adoption date August 28, 2025 Adoption date of Rule 10b5-1 trading plan covering these transactions

Key Terms

Rule 10b5-1 trading plan, Employee Stock Option (Right to Buy), derivative security

3 terms

Rule 10b5-1 trading plan regulatory

"This exercise and subsequent sale were made 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.

Employee Stock Option (Right to Buy) financial

"security_title: Employee Stock Option (Right to Buy)"

derivative security financial

"transaction_code_description: Exercise or conversion of derivative security"

A derivative security is a financial contract whose value comes from the price or performance of something else, such as a stock, bond, commodity, or market index. For investors it acts like an insurance policy or a wager: it can be used to protect against losses, lock in prices, or amplify gains and losses, so it can change a portfolio’s risk and potential return without owning the underlying asset directly.

FAQ

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

What insider transactions did Magnite (MGNI) executive Katie Seitz Evans report?

Katie Seitz Evans reported exercising employee stock options for 20,000 shares of Magnite common stock at $5.1600 per share and selling 20,000 shares of common stock at $24.0000 per share, all on August 6, 2026, in a single exercise-and-sell sequence.

At what prices were the Magnite (MGNI) option exercise and share sale executed?

The stock options were exercised at an exercise price of $5.1600 per share, and the resulting Magnite common shares were sold at $24.0000 per share. Both the option exercise and the share sale occurred on August 6, 2026 as part of the same transaction sequence.

How many Magnite (MGNI) shares did Katie Seitz Evans ultimately sell in this Form 4?

Katie Seitz Evans ultimately sold 20,000 shares of Magnite common stock. She first acquired 20,000 shares through an option exercise and then sold the same 20,000 shares at $24.0000 per share, resulting in a net sale of 20,000 shares for this reported activity.

Were Katie Seitz Evans’s Magnite (MGNI) trades under a Rule 10b5-1 trading plan?

Yes. The reported option exercise and share sale were conducted under a Rule 10b5-1 trading plan adopted by Katie Seitz Evans on August 28, 2025. This plan-based structure means the transactions followed a pre-established schedule rather than ad hoc trading decisions.

What is the status of the Magnite (MGNI) stock options involved in this Form 4?

The stock options involved were fully vested and immediately exercisable and were granted as compensation for services. After the reported exercise of 20,000 options, this particular option award shows 0 derivative shares remaining in the post-transaction holdings line.

What role does Katie Seitz Evans hold at Magnite (MGNI)?

Katie Seitz Evans is an officer of Magnite, serving as President, Product & Operations. Her reported transactions involve company equity received as compensation, including the exercised employee stock options and subsequent sale of Magnite common stock on August 6, 2026.

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

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Available on EDGAR 08/07/2026 - 05:06 PM Accepted by SEC EDGAR 08/07/2026 - 05:06 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).

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^*

Evans Katie Seitz

(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)
08/06/2026

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	08/06/2026		M(1)		20,000	A	$5.16	516,840	D
Common Stock	08/06/2026		S(1)		20,000	D	$24	496,840	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
Employee Stock Option (Right to Buy)	$5.16	08/06/2026		M(1)			20,000	(2)	02/27/2029	Common Stock	20,000	$0(3)	0	D

Explanation of Responses:

1. This exercise and subsequent sale were made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 28, 2025.

2. The stock options have fully vested and are immediately exercisable.

3. Granted as compensation for services.

Remarks:

President, Product & Operations

	/s/ Aaron Saltz, attorney-in-fact	08/07/2026
	** 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)