Magnite CEO sells 38,596 shares after option exercise

Magnite CEO Michael G. Barrett exercised employee stock options for 38,596 shares at $5.80 per share and sold 38,596 common shares at a weighted average price of $20.35 on July 15, 2026 under a Rule 10b5-1 plan adopted March 13, 2026.

Rhea-AI Filing Summary

Magnite CEO Michael G. Barrett exercised employee stock options for 38,596 shares at $5.80 per share and sold 38,596 common shares at a weighted average price of $20.35 on July 15, 2026 under a Rule 10b5-1 plan adopted March 13, 2026. After these trades, he holds 403,074 common shares and 293,968 remaining stock options expiring March 17, 2027.

Insider Trade Summary 10b5-1

Exercise and Sale: 38,596 shares ($562K approx. pre-tax spread)

Exercise and Sale 3 txns

Insider BARRETT MICHAEL G.

Role CEO

Sold 38,596 shs ($785K)

Approx. gross sale proceeds $785K

Approx. exercise cost $224K

Approx. pre-tax spread $562K

Type	Security	Shares	Price	Value
Exercise	Employee Stock Option (Right to Buy) F1, F4, F3	38,596	$0.00	$0.00
Exercise	Common Stock F1	38,596	$5.80	$224K
Sale	Common Stock F1, F2	38,596	$20.35	$785K

Holdings After Transaction: Employee Stock Option (Right to Buy) — 293,968 contracts (Direct); Common Stock — 403,074 shares (Direct)

Footnotes (4)

1. F1. This exercise and subsequent sale were made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on March 13, 2026.
2. F2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $20.165 to $20.56, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote to this Form 4.
3. F3. The stock options have fully vested and are immediately exercisable.
4. F4. Granted as compensation for services.

Key Figures

Shares sold: 38,596 shares Weighted average sale price: $20.35 per share Sale price range: $20.165–$20.56 per share +3 more

6 metrics

Shares sold 38,596 shares Common stock sold on 2026-07-15 at weighted average price

Weighted average sale price $20.35 per share Average price for 38,596 shares sold in multiple transactions

Sale price range $20.165–$20.56 per share Price range of individual sale trades on 2026-07-15

Options exercise price $5.80 per share Exercise price for 38,596 employee stock options converted to common stock

Common shares owned after 403,074 shares Direct Magnite common stock holdings following reported transactions

Options remaining after 293,968 options Employee stock options outstanding after partial exercise, expiring 2027-03-17

Key Terms

Rule 10b5-1 trading plan, weighted average price, Employee Stock Option (Right to Buy), immediately exercisable

4 terms

Rule 10b5-1 trading plan regulatory

"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.

weighted average price financial

"The price reported in Column 4 is a weighted average price."

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

Employee Stock Option (Right to Buy) financial

"security title is Employee Stock Option (Right to Buy) for the derivative position"

immediately exercisable financial

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

FAQ

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

What insider transaction did Magnite (MGNI) CEO Michael Barrett report?

Michael Barrett reported exercising employee stock options for 38,596 shares at $5.80 per share and selling 38,596 common shares at a weighted average price of $20.35 on July 15, 2026, under a pre-arranged Rule 10b5-1 trading plan.

At what prices did Michael Barrett sell Magnite (MGNI) shares?

Barrett sold 38,596 Magnite shares at a weighted average price of $20.35 per share. Footnotes state these shares traded in multiple transactions at prices ranging from $20.165 to $20.56, inclusive, on July 15, 2026.

How many Magnite (MGNI) shares does Michael Barrett own after this Form 4?

Following the July 15, 2026 transactions, Barrett directly owns 403,074 shares of Magnite common stock. He also holds 293,968 employee stock options after the reported option exercise reduced his derivative position.

Were Michael Barrett’s Magnite (MGNI) trades under a Rule 10b5-1 plan?

Yes. A footnote states the option exercise and subsequent share sale were made under a Rule 10b5-1 trading plan adopted by Barrett on March 13, 2026. The filing also checks the Rule 10b5-1 plan affirmation box.

What stock options did Michael Barrett exercise in Magnite (MGNI)?

Barrett exercised 38,596 employee stock options with an exercise price of $5.80 per share, reducing that option grant to 293,968 options remaining. A footnote notes these options were granted as compensation and are fully vested and immediately exercisable.

When do Michael Barrett’s remaining Magnite (MGNI) options expire?

The employee stock options reported in this Form 4, after partial exercise, leave 293,968 options outstanding with an expiration date of March 17, 2027. These options relate to Magnite common stock and are fully vested according to the footnotes.

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

Form 4 Insider Transactions: What Each Field Means →

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Accepted by SEC EDGAR 07/17/2026 - 05:00 PM EDT 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^*

BARRETT MICHAEL G.

(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)

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	CEO

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
07/15/2026

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	07/15/2026		M(1)		38,596	A	$5.8	441,670	D
Common Stock	07/15/2026		S(1)		38,596	D	$20.35(2)	403,074	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)	$5.8	07/15/2026		M(1)			38,596	(3)	03/17/2027	Common Stock	38,596	$0(4)	293,968	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 March 13, 2026.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $20.165 to $20.56, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote to this Form 4.

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

4. Granted as compensation for services.

	/s/ Aaron Saltz, attorney-in-fact	07/17/2026
	** 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)