Magnite CTO sells 1,224 shares in planned trade

Magnite, Inc. Chief Technology Officer David Buonasera reported an open-market sale of 1,224 shares of Common Stock at $21.00 per share.

Rhea-AI Filing Summary

Magnite, Inc. Chief Technology Officer David Buonasera reported an open-market sale of 1,224 shares of Common Stock at $21.00 per share. After this transaction, he directly holds 268,485 shares.

The sale was executed under a pre-arranged Rule 10b5-1 trading plan adopted on September 11, 2025, indicating it was scheduled in advance rather than timed opportunistically.

Insider Trade Summary 10b5-1

Net Seller: 1,224 shares

Net Sell 1 txn

Insider Buonasera David

Role CHIEF TECHNOLOGY OFFICER

Sold 1,224 shs ($26K)

Type	Security	Shares	Price	Value
Sale	Common Stock	1,224	$21.00	$26K

Holdings After Transaction: Common Stock — 268,485 shares (Direct)

Footnotes (1)

1. F1. The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on September 11, 2025.

Key Figures

Shares sold: 1,224 shares Sale price: $21.00 per share Shares held after transaction: 268,485 shares +2 more

5 metrics

Shares sold 1,224 shares Open-market sale of Common Stock on July 7, 2026

Sale price $21.00 per share Execution price for 1,224 shares sold

Shares held after transaction 268,485 shares Direct Common Stock holdings following the sale

Rule 10b5-1 plan adoption date September 11, 2025 Date CTO adopted trading plan governing this sale

Transaction code S Sale in open market or private transaction

Key Terms

Rule 10b5-1 trading plan, open-market sale, Common Stock, Form 4

4 terms

Rule 10b5-1 trading plan regulatory

"The reported transaction was effected 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.

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.

Common Stock financial

"security_title: "Common Stock""

Common stock represents ownership shares in a company, giving investors a stake in its success and a say in important decisions through voting rights. It is the most common type of stock traded on markets and can provide income through dividends, as well as potential for value growth. For investors, holding common stock means sharing in the company’s profits and risks.

Form 4 regulatory

"INSIDER FILING DATA (Form 4)"

Form 4 is a official document that company insiders, such as executives or major shareholders, file with regulators whenever they buy or sell company shares. It provides transparency about how those with inside knowledge are trading, helping investors see if insiders are confident in the company's prospects or may be selling for personal reasons. This information can influence investor decisions by revealing insiders' perspectives on the company's value.

FAQ

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

What insider transaction did MAGNITE, INC. (MGNI) report for David Buonasera?

MAGNITE, INC. reported that Chief Technology Officer David Buonasera sold 1,224 shares of Common Stock at $21.00 per share. The transaction was an open-market sale and was disclosed in a Form 4 insider trading report.

How many MAGNITE, INC. (MGNI) shares does David Buonasera hold after this sale?

After selling 1,224 shares, David Buonasera directly holds 268,485 shares of MAGNITE, INC. Common Stock. This post-transaction balance shows he retains a substantial equity position despite the reported open-market sale.

At what price did the MAGNITE, INC. (MGNI) CTO sell his shares?

David Buonasera sold 1,224 shares of MAGNITE, INC. Common Stock at $21.00 per share. This price reflects the execution level for the reported open-market transaction on the Form 4 filing.

Was the MAGNITE, INC. (MGNI) insider sale made under a Rule 10b5-1 plan?

Yes. The filing states the transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by David Buonasera on September 11, 2025. Such plans pre-schedule trades to reduce concerns about trade timing.

What type of transaction did MAGNITE, INC. (MGNI) disclose in this Form 4?

MAGNITE, INC. disclosed an open-market sale of Common Stock by its Chief Technology Officer. The Form 4 classifies the transaction with code “S,” indicating a sale in an open market or private transaction setting.

Does the MAGNITE, INC. (MGNI) Form 4 show any derivative securities activity?

No derivative securities activity is shown in this Form 4. The derivativeSummary section is empty, indicating the reported activity relates only to non-derivative Common Stock rather than options, warrants, or other derivatives.

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 07/09/2026 - 04:32 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^*

Buonasera 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 TECHNOLOGY OFFICER

2a. Foreign Trading Symbol

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

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	07/07/2026		S(1)		1,224	D	$21	268,485	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. The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on September 11, 2025.

	/s/ Aaron Saltz, attorney-in-fact	07/09/2026
	** 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)