Magnite officer Buonasera proposes $23.9K share sale

The proposed shares were acquired from the issuer as restricted stock units, and two earlier sales are labeled as 10b5-1 sales.

Available on EDGAR 11/09/2026 - 04:38 PM EST Accepted by SEC EDGAR 11/09/2026 - 04:37 PM EST Learn about SEC filing dates

Rhea-AI Filing Summary

Magnite, Inc. (MGNI) reports a proposed sale by officer David Buonasera of 871 common shares, with an aggregate market value of $23,856.69 and an approximate sale date of November 9, 2026. The shares were acquired from the issuer as restricted stock units on May 15, 2025. June 13, 2026 is listed as the date of plan adoption or instruction if relying on Rule 10b5-1. Earlier sales reported for the prior three months include 5,706 shares for gross proceeds of $155,496.00 on November 5, 2026 and 1,165 shares for $27,960.00 on September 14, 2026, both labeled 10b5-1 sales; other reported sales were 1,043 shares for $26,075.00 on September 2, 2026 and 5,371 shares for $125,788.82 on September 1, 2026.

Key Figures

Proposed shares to be sold: 871 common shares Aggregate market value: $23,856.69 Approximate sale date: November 9, 2026

3 metrics

Proposed shares to be sold 871 common shares Approximate sale date November 9, 2026

Aggregate market value $23,856.69 Proposed sale

Approximate sale date November 9, 2026 Proposed sale

Key Terms

Rule 10b5-1, Restricted Stock Units, Aggregate Market Value

3 terms

Rule 10b5-1 regulatory

"Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1"

Rule 10b5-1 is a regulation that allows company insiders to buy or sell their shares at predetermined times, even if they have access to non-public information. It acts like setting a schedule in advance for transactions, helping prevent accusations of unfair trading. This rule provides a way for insiders to plan trades transparently, giving investors confidence that these transactions are not based on hidden information.

Restricted Stock Units financial

"Nature of Acquisition Transaction: Restricted Stock Units"

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

"Aggregate Market Value"

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.

FAQ

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

How many MGNI shares does David Buonasera plan to sell?

He reported a proposed sale of 871 common shares, with an aggregate market value of $23,856.69 and an approximate sale date of November 9, 2026. The shares were acquired from the issuer as restricted stock units on May 15, 2025.

What recent shares has David Buonasera sold?

He reported four sales: 5,706 shares for gross proceeds of $155,496.00 on November 5, 2026; 1,165 shares for $27,960.00 on September 14, 2026; 1,043 shares for $26,075.00 on September 2, 2026; and 5,371 shares for $125,788.82 on September 1, 2026. The November 5 and September 14 sales are labeled 10b5-1 sales.

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

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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	871	23856.69	143559468	11/09/2026	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	05/15/2025	Restricted Stock Units	Issuer			871	05/15/2025	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
10b5-1 Sales for DAVID BUONASERA 1250 Broadway, 9th Floor New York NY 10001	Common	11/05/2026	5706	155496.00
10b5-1 Sales for DAVID BUONASERA 1250 Broadway, 9th Floor New York NY 10001	Common	09/14/2026	1165	27960.00
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

144: Remarks and Signature

Remarks
Date of Notice	11/09/2026
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 Buoanesera
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)