Magnite officer may sell $125,788 in stock

Rhea-AI Filing Summary

MAGNITE, INC. (MGNI) received a Rule 144 notice that officer David Buonasera may sell up to 5,371 shares of common stock through Morgan Stanley Smith Barney LLC on or after 09/01/2026. The shares are restricted stock acquired from the issuer on 08/15/2025, and prior sales over the last three months are also listed.

Key Figures

Shares to be sold: 5,371 shares Aggregate market value of shares to be sold: $125,788.82 Proposed sale date: 09/01/2026 +3 more

6 metrics

Shares to be sold 5,371 shares Common stock covered by the Rule 144 notice

Aggregate market value of shares to be sold $125,788.82 Market value associated with 5,371 shares in the securities information section

Proposed sale date 09/01/2026 Date of sale listed for the 5,371 shares of common stock

Sale on 08/06/2026 7,649 shares for $179,459.56 Common stock sold by David Buonasera during the past 3 months

Sale on 07/01/2026 9,376 shares for $187,520.00 Common stock sold by David Buonasera during the past 3 months

Sale on 06/16/2026 11,233 shares for $202,194.00 Common stock sold by David Buonasera during the past 3 months

Key Terms

Rule 144, restricted stock, aggregate, NASDQ

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 financial

"| 5371 | 125788.82 | 143424157 | 09/01/2026 |"

A combined total or summary created by adding together multiple parts or data points. Used as a noun and a verb, it means pooling individual items (sales, revenues, assets, transactions, or data) into one overall figure so stakeholders can see the big picture; like pouring many small jars into a single container to measure the total amount. Aggregate figures matter to investors because they show the overall size, trend, or exposure of a business or market rather than the detail of each component.

NASDQ market

"143424157 | 09/01/2026 | NASDAQ"

FAQ

What does this Form 144 filing mean for MAGNITE, INC. (MGNI)?

The filing gives notice that officer David Buonasera may sell up to 5,371 shares of MAGNITE, INC. common stock under Rule 144. It is a disclosure of a potential sale by an affiliate, not by the company itself.

How many MGNI shares are covered by this Form 144 notice?

The notice covers up to 5,371 shares of MAGNITE, INC. common stock. The securities information section shows 5,371 shares with an aggregate market value of $125,788.82 and a proposed sale date of 09/01/2026.

Who is selling MAGNITE, INC. (MGNI) shares in this Form 144?

The potential sale is for the account of David Buonasera, identified as an officer of MAGNITE, INC. His address is listed as the company’s New York office, and the filing aggregates his Rule 144 activity over the relevant period.

What type of MAGNITE, INC. securities are involved in this Form 144?

The securities are common stock, described as restricted stock acquired from the issuer on 08/15/2025. The trading market is listed as NASDAQ, and Morgan Stanley Smith Barney LLC is identified as the broker handling the transaction.

What MGNI share sales has David Buonasera reported in the past 3 months?

Over the past three months he reported six sales totaling multiple transactions: 7,649 shares for $179,459.56 on 08/06/2026, 1,224 shares for $25,704.00 on 07/07/2026, 9,376 shares for $187,520.00 on 07/01/2026, 1,409 shares for $26,771.00 on 06/17/2026, 11,233 shares for $202,194.00 on 06/16/2026, and 1,057 shares for $17,969.00 on 06/15/2026.

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

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Available on EDGAR 09/01/2026 - 04:16 PM Accepted by SEC EDGAR 09/01/2026 - 04:15 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	5371	125788.82	143424157	09/01/2026	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			5371	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	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	09/01/2026
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)