MAGNITE (MGNI) CEO Barrett exercises options and sells 75,000 shares under 10b5-1 plan

Rhea-AI Filing Summary

MAGNITE, INC. CEO Michael G. Barrett reported an option exercise and related share sale in Common Stock. He exercised options for 75,000 shares at $5.80 per share and sold 75,000 shares in an open-market transaction at $19.50 per share.

Following these transactions, Barrett holds 403,074 shares of Common Stock directly. The exercise and subsequent sale were carried out under a pre-arranged Rule 10b5-1 trading plan, indicating the trades were scheduled in advance as part of a structured liquidity plan.

Insights

Equity compensation and insider-trading analyst

Planned exercise-and-sell by CEO under 10b5-1, routine in nature.

CEO Michael G. Barrett exercised employee stock options for 75,000 shares of MAGNITE, INC. Common Stock at $5.80 per share and sold the same 75,000 shares at $19.50 per share. This is a classic exercise-and-sell pattern converting option value into cash.

The filing notes these transactions were executed under a Rule 10b5-1 trading plan adopted on March 13, 2026, and the options were fully vested and granted as compensation. After the transactions, Barrett directly holds 403,074 shares. The pre-planned nature and limited scale relative to his remaining holdings make this look like routine portfolio management rather than a directional signal.

Insider Trade Summary 10b5-1

Net Seller: 75,000 shares ($1,462,500)

Net Sell 3 txns

Insider BARRETT MICHAEL G.

Role CEO

Sold 75,000 shs ($1.46M)

Type	Security	Shares	Price	Value
Exercise	Employee Stock Option (Right to Buy)	75,000	$0.00	--
Exercise	Common Stock	75,000	$5.80	$435K
Sale	Common Stock	75,000	$19.50	$1.46M

Holdings After Transaction: Employee Stock Option (Right to Buy) — 332,564 shares (Direct, null); Common Stock — 478,074 shares (Direct, null)

Footnotes (1)

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. The stock options have fully vested and are immediately exercisable. Granted as compensation for services.

Key Figures

Shares sold: 75,000 shares Sale price: $19.50 per share Options exercised: 75,000 shares +4 more

7 metrics

Shares sold 75,000 shares Open-market sale of Common Stock

Sale price $19.50 per share Price for 75,000 Common Stock shares sold

Options exercised 75,000 shares Employee Stock Option (Right to Buy) exercise

Exercise price $5.80 per share Exercise price of employee stock options

Shares held after 403,074 shares Common Stock directly owned post-transaction

Rule 10b5-1 plan adoption date March 13, 2026 Plan governing exercise and sale transactions

Option expiration March 17, 2027 Expiration date of employee stock option grant

Key Terms

Rule 10b5-1 trading plan, Employee Stock Option (Right to Buy), Exercise or conversion of derivative security, open-market sale, +1 more

5 terms

Rule 10b5-1 trading plan regulatory

"This exercise and subsequent sale were made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person"

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)""

Exercise or conversion of derivative security financial

"transaction_code_description": "Exercise or conversion of derivative security""

open-market sale financial

"transaction_action": "open-market sale""

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

fully vested financial

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

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 07/01/2026 - 04:51 PM Accepted by SEC EDGAR 07/01/2026 - 04:49 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^*

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)
06/29/2026

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	06/29/2026		M(1)		75,000	A	$5.8	478,074	D
Common Stock	06/29/2026		S(1)		75,000	D	$19.5	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	06/29/2026		M(1)			75,000	(2)	03/17/2027	Common Stock	75,000	$0(3)	332,564	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 stock options have fully vested and are immediately exercisable.

3. Granted as compensation for services.

	/s/ Aaron Saltz, attorney-in-fact	07/01/2026
	** 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)

FAQ

What did MAGNITE (MGNI) CEO Michael G. Barrett report in this Form 4?

Michael G. Barrett reported exercising options for 75,000 MAGNITE shares at $5.80 and selling 75,000 shares at $19.50. These transactions convert option-based compensation into cash while leaving him with a substantial remaining equity stake.

How many MAGNITE (MGNI) shares does the CEO hold after the reported transactions?

After the reported transactions, Michael G. Barrett directly holds 403,074 shares of MAGNITE Common Stock. This figure reflects his position following the 75,000-share option exercise and the related 75,000-share open-market sale disclosed in the Form 4.

At what prices did the MAGNITE (MGNI) CEO exercise and sell shares?

Michael G. Barrett exercised employee stock options at an exercise price of $5.80 per share and sold 75,000 MAGNITE Common Stock shares at $19.50 per share. The spread between these prices represents the realized value of his stock option award.

Was the MAGNITE (MGNI) CEO’s stock sale part of a pre-planned 10b5-1 program?

Yes. The filing states the option exercise and subsequent sale were made under a Rule 10b5-1 trading plan adopted on March 13, 2026. Such plans pre-schedule trades, helping separate routine liquidity events from discretionary timing decisions.

What type of derivative security did the MAGNITE (MGNI) CEO exercise?

Michael G. Barrett exercised an Employee Stock Option (Right to Buy) covering 75,000 underlying MAGNITE Common Stock shares at an exercise price of $5.80. The filing notes the options were fully vested, immediately exercisable, and granted as compensation for services.