Magnite officer plans $26K stock sale

Magnite officer David Buonasera filed a Rule 144 notice to sell 1,043 shares of common stock against a base of over 143 million shares outstanding.

Rhea-AI Filing Summary

MAGNITE, INC. (MGNI) is the issuer for a Rule 144 notice filed by officer David Buonasera, covering a proposed sale of 1,043 shares of common stock through Morgan Stanley Smith Barney LLC, with an aggregate market value of $26,075.00 and 143,424,157 shares outstanding as of the planned sale date of September 2, 2026. The shares were acquired as restricted stock from the issuer on August 15, 2025. The filing also lists prior open-market sales by Buonasera over the past three months, including several transactions in June, July, August, and September 2026 with individual trade sizes ranging from 1,057 to 11,233 shares.

Key Figures

Shares to be sold under Rule 144: 1,043 shares Aggregate market value of proposed sale: $26,075.00 Shares outstanding: 143,424,157 shares +4 more

7 metrics

Shares to be sold under Rule 144 1,043 shares Magnite common stock proposed for sale by David Buonasera

Aggregate market value of proposed sale $26,075.00 Value of 1,043 Magnite shares in the Rule 144 notice

Shares outstanding 143,424,157 shares Magnite common shares outstanding as of planned sale date September 2, 2026

Acquisition date of shares August 15, 2025 Date 1,043 restricted shares were acquired from the issuer

Sale on June 16, 2026 11,233 shares for $202,194.00 Common stock sold by David Buonasera in prior three months

Sale on July 1, 2026 9,376 shares for $187,520.00 Common stock sold by David Buonasera in prior three months

Sale on September 1, 2026 5,371 shares for $125,788.82 Most recent prior sale listed in the three-month history

Key Terms

Rule 144, Restricted Stock, aggregate market value, securities to be sold

4 terms

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 financial

"Common | 08/15/2025 | Restricted Stock | ISSUER"

Shares granted to an individual that carry limits on transfer or sale until certain conditions are met, such as staying with the company for a set time or hitting performance targets. Think of them as a locked gift that gradually opens; for investors they matter because they affect how many shares may enter the market later, signal management incentives and potential dilution, and reveal confidence in future company performance.

aggregate market value financial

"Common ... 1043 | 26075.00 | 143424157"

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.

securities to be sold regulatory

"Name of Person for Whose Account the Securities are To Be Sold"

FAQ

What does the Rule 144 filing for MAGNITE, INC. (MGNI) disclose?

The notice discloses that officer David Buonasera plans to sell 1,043 shares of Magnite common stock under Rule 144, using Morgan Stanley Smith Barney LLC as broker, with an aggregate market value of $26,075.00 as of the planned sale date.

How many MAGNITE, INC. (MGNI) shares are covered by this Rule 144 sale?

The filing covers a proposed sale of 1,043 shares of Magnite common stock. These shares were acquired as restricted stock on August 15, 2025 from the issuer.

How many MAGNITE, INC. (MGNI) shares were outstanding at the time of the planned Rule 144 sale?

The filing states that 143,424,157 shares of Magnite common stock were outstanding as of the planned sale date of September 2, 2026, providing context for the relative size of the 1,043-share sale.

What is the aggregate market value of the MAGNITE, INC. (MGNI) shares in this Rule 144 notice?

The proposed 1,043-share sale has an aggregate market value of $26,075.00, as reported in the Rule 144 filing for Magnite common stock.

What prior MAGNITE, INC. (MGNI) share sales by David Buonasera are listed in the past three months?

The filing lists several prior sales, including 11,233 shares on June 16, 2026 for $202,194.00 and 9,376 shares on July 1, 2026 for $187,520.00, along with additional smaller trades in June, July, August, and September 2026.

How and when were the MAGNITE, INC. (MGNI) shares in this Rule 144 filing acquired?

The 1,043 shares covered by this notice were acquired on August 15, 2025 as restricted stock from the issuer, Magnite, Inc., with the form stating the nature of payment as Not Applicable.

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

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Available on EDGAR 09/02/2026 - 04:17 PM Accepted by SEC EDGAR 09/02/2026 - 04:16 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	(212) 243-2769
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	1043	26075.00	143424157	09/02/2026	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	08/15/2025	Restricted Stock	ISSUER			1043	08/15/2025	Not Applicable

* 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	09/01/2026	5371	125788.82
DAVID BUONASERA 1250 Broadway, 9th Floor New York, NY 10001	Common	08/06/2026	7649	179459.56
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	09/02/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	09/11/2025
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)