Magnite (NASDAQ: MGNI) CTO sells 9,376 shares in $20 open-market trade

Rhea-AI Filing Summary

MAGNITE, INC. Chief Technology Officer David Buonasera sold 9,376 shares of Common Stock in an open-market transaction at $20.00 per share. After the sale, he directly holds 269,709 shares. The transaction was carried out under a pre-arranged Rule 10b5-1 trading plan adopted on September 11, 2025.

Insider Trade Summary 10b5-1

Net Seller: 9,376 shares ($187,520)

Net Sell 1 txn

Insider Buonasera David

Role CHIEF TECHNOLOGY OFFICER

Sold 9,376 shs ($188K)

Type	Security	Shares	Price	Value
Sale	Common Stock	9,376	$20.00	$188K

Holdings After Transaction: Common Stock — 269,709 shares (Direct, null)

Footnotes (1)

1. [object Object]

Key Figures

Shares sold: 9,376 shares Sale price: $20.00 per share Shares held after transaction: 269,709 shares +1 more

4 metrics

Shares sold 9,376 shares Open-market sale of Common Stock

Sale price $20.00 per share Price for the 9,376 shares sold

Shares held after transaction 269,709 shares Direct ownership following the sale

Net share change -9,376 shares Net-sell direction in transaction summary

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.

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 07/02/2026 - 07:08 PM Accepted by SEC EDGAR 07/02/2026 - 07:07 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^*

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)
07/01/2026

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	07/01/2026		S(1)		9,376	D	$20	269,709	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	07/02/2026
	** 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 transaction did MAGNITE (MGNI) report for its CTO?

MAGNITE’s Chief Technology Officer David Buonasera sold 9,376 shares of Common Stock. The shares were sold in an open-market transaction at $20.00 per share, and the sale was executed under a pre-arranged Rule 10b5-1 trading plan.

How many MAGNITE (MGNI) shares does the CTO hold after this Form 4 sale?

Following the reported sale, Chief Technology Officer David Buonasera directly owns 269,709 shares of MAGNITE Common Stock. This figure reflects his holdings after disposing of 9,376 shares in the open market at $20.00 per share.

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

The CTO’s open-market sale was executed at $20.00 per share. In total, 9,376 shares of MAGNITE Common Stock were sold at this price under a Rule 10b5-1 trading plan adopted on September 11, 2025.

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

Yes. The filing states the transaction was effected under a Rule 10b5-1 trading plan adopted by the reporting person on September 11, 2025. Such plans are pre-arranged and automate trades according to preset instructions.

Who is the insider involved in this MAGNITE (MGNI) Form 4 filing?

The insider is David Buonasera, Chief Technology Officer of MAGNITE, INC. He reported selling 9,376 shares of Common Stock at $20.00 per share and now directly holds 269,709 shares after the transaction.