Magnite (NASDAQ: MGNI) CEO sells shares after exercising stock options

Rhea-AI Filing Summary

Magnite, Inc. CEO Michael G. Barrett exercised stock options and sold shares in paired transactions disclosed on this Form 4. On June 15, 2026, he exercised options to acquire 178,596 shares of common stock at a $5.80 exercise price and sold 178,596 shares in open‑market transactions at a weighted average price of $16.59, with individual trades ranging from $15.945 to $16.93. On June 16, 2026, he exercised options to acquire an additional 100,000 shares at $5.80 and sold 100,000 shares at $17.50 per share. The filing reports that these exercises and subsequent sales were made pursuant to a pre‑arranged Rule 10b5‑1 trading plan adopted on March 13, 2026. Following the transactions, Barrett directly holds 403,074 shares of Magnite common stock, with the reported options fully vested and immediately exercisable before their stated expiration date of March 17, 2027.

Insights

Equity compensation and insider-trading analyst

Magnite’s CEO executed a routine option exercise-and-sell under a pre-set Rule 10b5-1 plan, while retaining a substantial share position.

CEO Michael G. Barrett exercised employee stock options with a $5.80 exercise price to acquire a total of 278,596 Magnite common shares, then sold the same number of shares in open‑market trades around $16–$17.50 per share. This pattern converts option value into cash without increasing net share ownership.

The filing notes that these exercises and sales were made pursuant to a Rule 10b5‑1 trading plan adopted on March 13, 2026, indicating the trades were pre‑scheduled rather than opportunistic. After these transactions, Barrett still directly holds 403,074 shares, and the underlying options referenced are fully vested and exercisable until March 17, 2027, suggesting ongoing equity exposure alongside routine liquidity management.

Insider Trade Summary 10b5-1

Net Seller: 278,596 shares ($4,712,908)

Net Sell 6 txns

Insider BARRETT MICHAEL G.

Role CEO

Sold 278,596 shs ($4.71M)

Type	Security	Shares	Price	Value
Exercise	Employee Stock Option (Right to Buy)	100,000	$0.00	--
Exercise	Common Stock	100,000	$5.80	$580K
Sale	Common Stock	100,000	$17.50	$1.75M
Exercise	Employee Stock Option (Right to Buy)	178,596	$0.00	--
Exercise	Common Stock	178,596	$5.80	$1.04M
Sale	Common Stock	178,596	$16.59	$2.96M

Holdings After Transaction: Employee Stock Option (Right to Buy) — 407,564 shares (Direct, null); Common Stock — 503,074 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 price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $15.945 to $16.93, 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. The stock options have fully vested and are immediately exercisable. Granted as compensation for services.

Key Figures

Shares sold: 278,596 shares Option exercise shares: 278,596 shares Exercise price: $5.80 per share +5 more

8 metrics

Shares sold 278,596 shares Total Magnite common shares sold in open market on June 15–16, 2026

Option exercise shares 278,596 shares Shares acquired via employee stock option exercises at $5.80

Exercise price $5.80 per share Employee stock option conversion or exercise price

Sale price (block 1) $16.59 per share Weighted average price for 178,596 shares sold on June 15, 2026

Sale price (block 2) $17.50 per share Price for 100,000 shares sold on June 16, 2026

Post-transaction holdings 403,074 shares Magnite common shares directly held by CEO after transactions

Option expiration March 17, 2027 Expiration date of the exercised employee stock options

10b5-1 plan adoption date March 13, 2026 Date CEO adopted Rule 10b5-1 trading plan governing these trades

Key Terms

Rule 10b5-1 trading plan, Employee Stock Option (Right to Buy), weighted average price, derivative security, +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 on March 13, 2026."

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)" with a conversion or exercise price of 5.8000."

weighted average price financial

"The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $15.945 to $16.93, inclusive."

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.

derivative security financial

"transaction_code_description: "Exercise or conversion of derivative security" for the option exercises reported."

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.

open-market sale financial

"transaction_action: "open-market sale" with transaction_code "S" for Magnite common stock."

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.

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Form 4 Insider Transactions: What Each Field Means →

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)
06/15/2026

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	06/15/2026		M(1)		178,596	A	$5.8	581,670	D
Common Stock	06/15/2026		S(1)		178,596	D	$16.59(2)	403,074	D
Common Stock	06/16/2026		M(1)		100,000	A	$5.8	503,074	D
Common Stock	06/16/2026		S(1)		100,000	D	$17.5	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	06/15/2026		M(1)			178,596	(3)	03/17/2027	Common Stock	178,596	$0(4)	507,564	D
Employee Stock Option (Right to Buy)	$5.8	06/16/2026		M(1)			100,000	(3)	03/17/2027	Common Stock	100,000	$0(4)	407,564	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 price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $15.945 to $16.93, 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	06/17/2026
	** 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)

FAQ

What insider transactions did Magnite (MGNI) CEO Michael Barrett report on this Form 4?

Magnite CEO Michael Barrett reported exercising employee stock options to acquire 278,596 common shares at a $5.80 exercise price, then selling 278,596 shares in open‑market transactions around $16–$17.50 per share over June 15–16, 2026 under a disclosed trading plan.

How many Magnite (MGNI) shares does the CEO hold after these June 2026 transactions?

After completing the reported transactions, CEO Michael Barrett directly holds 403,074 shares of Magnite common stock. This figure reflects his remaining position following the option exercises and the matched open‑market sales disclosed in the June 2026 Form 4 filing.

Were Michael Barrett’s Magnite (MGNI) share sales made under a Rule 10b5-1 trading plan?

Yes. The Form 4 footnotes state that the option exercises and subsequent share sales were made pursuant to a Rule 10b5‑1 trading plan adopted by Michael Barrett on March 13, 2026, indicating the transactions were pre‑arranged rather than discretionary market‑timed trades.

What prices did the Magnite (MGNI) CEO receive for the shares sold in June 2026?

The filing reports one sale of 178,596 shares at a weighted average price of $16.59, with individual trades between $15.945 and $16.93, and another sale of 100,000 shares at $17.50 per share. All were open‑market transactions in Magnite common stock.

What was the exercise price and expiration date of the Magnite (MGNI) stock options exercised?

The employee stock options exercised by Michael Barrett had a conversion or exercise price of $5.80 per share and an expiration date of March 17, 2027. The footnotes indicate these stock options were fully vested and immediately exercisable at the time of the reported transactions.

Does this Magnite (MGNI) Form 4 indicate any remaining stock options for the CEO?

The filing shows option exercises covering 278,596 shares, with those stock options described as fully vested and immediately exercisable and having a March 17, 2027 expiration. The derivative summary shows no remaining derivative positions in this specific Form 4 excerpt.