Magnite officer plans sale of 1,165 shares, $27K

An officer of MAGNITE, INC. filed Form 144 to sell 1,165 shares, alongside disclosure of multiple recent MAGNITE stock sales.

Rhea-AI Filing Summary

MAGNITE, INC. (MGNI) is the issuer for which officer David Buonasera has filed a Form 144 notice to sell common stock. The notice covers 1,165 shares of common stock, to be sold through Morgan Stanley Smith Barney LLC, with an aggregate market value of $27,692.05 on NASDAQ.

The securities to be sold arise from Restricted Stock Units that became available on August 15, 2026. The filing also lists a series of past open-market sales of MAGNITE common stock by Buonasera over the prior three months, with individual transactions ranging from about 1,000 to over 11,000 shares.

Key Figures

Planned shares to be sold: 1,165 shares Planned sale aggregate value: $27,692.05 Sale on September 2, 2026: 1,043 shares for $26,075.00 +3 more

6 metrics

Planned shares to be sold 1,165 shares Common stock covered by current Form 144 notice

Planned sale aggregate value $27,692.05 Aggregate market value for 1,165 shares of common stock

Sale on September 2, 2026 1,043 shares for $26,075.00 Common stock sold by David Buonasera

Sale on September 1, 2026 5,371 shares for $125,788.82 Common stock sold by David Buonasera

Largest single recent sale 11,233 shares for $202,194.00 Common stock sale on June 16, 2026

Sale on August 6, 2026 7,649 shares for $179,445.54 Common stock sold by David Buonasera

Key Terms

Form 144, Rule 144, Restricted Stock Units, aggregate market value, +1 more

5 terms

Form 144 regulatory

"Officer David Buonasera has filed a Form 144 notice to sell common stock"

Form 144 is a document that investors must file with the government when they plan to sell a large number of shares of a company's stock. It helps ensure transparency so everyone knows how many shares are being sold and when, which can impact the stock's price.

Rule 144 regulatory

"See the definition of "person" in paragraph (a) of Rule 144"

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

Restricted Stock Units financial

"Common | 08/15/2026 | Restricted Stock Units | Issuer"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

aggregate market value financial

"with an aggregate market value of $27,692.05 on NASDAQ"

Aggregate market value is the combined price you would pay to buy all outstanding shares of a company or all companies in a group at current market prices — essentially the sum of each stock’s market capitalization. It matters to investors because it shows the overall size and weight of an investment or sector (like the total cost to buy every piece of a puzzle), helps compare scale across companies or markets, and influences index composition and risk exposure.

common stock financial

"The notice covers 1,165 shares of 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.

FAQ

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

What does MAGNITE, INC. (MGNI) disclose in this Form 144 filing?

The filing states that officer David Buonasera intends to sell 1,165 shares of MAGNITE common stock under Rule 144 and discloses several prior sales of MAGNITE common stock over the past three months.

How many MAGNITE (MGNI) shares are covered by the new planned sale?

The Form 144 covers a planned sale of 1,165 shares of MAGNITE, INC. common stock, to be sold through Morgan Stanley Smith Barney LLC on NASDAQ, with an indicated aggregate market value of $27,692.05.

What is the source of the MAGNITE (MGNI) shares to be sold under this Form 144?

The filing states that the common shares to be sold are from Restricted Stock Units related to MAGNITE, INC., with a date of August 15, 2026 listed for the RSU securities to be sold.

Which broker is handling the planned MAGNITE (MGNI) stock sale?

The Form 144 lists Morgan Stanley Smith Barney LLC Executive Financial Services, located at 1 New York Plaza in New York, as the broker handling the planned sale of MAGNITE common stock.

What MAGNITE (MGNI) stock sales by David Buonasera occurred in the past three months?

The filing lists multiple common stock sales, including 1,043 shares for $26,075.00 on September 2, 2026, 5,371 shares for $125,788.82 on September 1, 2026, and several June–August 2026 sales ranging from about 1,000 to over 11,000 shares.

Who is the insider associated with this MAGNITE (MGNI) Form 144?

The Form 144 identifies David Buonasera, listed as an Officer of MAGNITE, INC., as the person for whose account the MAGNITE common stock is to be sold.

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

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Available on EDGAR 09/14/2026 - 05:11 PM Accepted by SEC EDGAR 09/14/2026 - 04:45 PM Learn about SEC filing dates

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001966857
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	MAGNITE, INC.
SEC File Number	001-36384
Address of Issuer	1250 Broadway, 9th Floor New York NEW YORK 10001
Phone	2122432769
Name of Person for Whose Account the Securities are To Be Sold	DAVID BUONASERA
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Officer

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common	Morgan Stanley Smith Barney LLC Executive Financial Services 1 New York Plaza 8th Floor New York NY 10004	1165	27692.05	143424157	09/14/2026	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common	08/15/2026	Restricted Stock Units	Issuer			1165	08/15/2026	N/A

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
DAVID BUONASERA 1250 Broadway, 9th Floor New York NY 10001	Common	09/02/2026	1043	26075.00
DAVID BUONASERA 1250 Broadway, 9th Floor New York NY 10001	Common	09/01/2026	5371	125788.82
DAVID BUONASERA 1250 Broadway, 9th Floor New York NY 10001	Common	08/06/2026	7649	179445.54
DAVID BUONASERA 1250 Broadway, 9th Floor New York NY 10001	Common	07/07/2026	1224	25704.00
DAVID BUONASERA 1250 Broadway, 9th Floor New York NY 10001	Common	07/01/2026	9376	187520.00
DAVID BUONASERA 1250 Broadway, 9th Floor New York NY 10001	Common	06/17/2026	1409	26771.00
DAVID BUONASERA 1250 Broadway, 9th Floor New York NY 10001	Common	06/16/2026	11233	202194.00
DAVID BUONASERA 1250 Broadway, 9th Floor New York NY 10001	Common	06/15/2026	1057	17969.00

144: Remarks and Signature

Remarks
Date of Notice	09/14/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	06/13/2026
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/ David Matthew Buoanesera
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)