Magnite director plans $442K Rule 144 stock sale

Magnite, Inc. (MGNI) is the issuer for which director Sarah Patricia Harden filed a Form 144, giving notice of a proposed sale of restricted common stock under Rule 144.

Rhea-AI Filing Summary

Magnite, Inc. (MGNI) is the issuer for which director Sarah Patricia Harden filed a Form 144, giving notice of a proposed sale of restricted common stock under Rule 144. The notice covers 18,436 shares of common stock with an aggregate market value of $442,464.00, to be sold through Morgan Stanley Smith Barney LLC on NASDAQ around 08/28/2026. Magnite reports 143,424,157 shares of common stock outstanding; this is a baseline figure, not the amount being sold. The filing also lists a separate sale during the past three months of 30,550 shares of common stock on 08/26/2026 for $712,166.86.

Key Figures

Shares to be sold: 18,436 shares of common stock Aggregate market value of proposed sale: $442,464.00 Shares outstanding: 143,424,157 shares +3 more

6 metrics

Shares to be sold 18,436 shares of common stock Proposed sale under Rule 144 through Morgan Stanley Smith Barney LLC

Aggregate market value of proposed sale $442,464.00 Value of 18,436 Magnite, Inc. common shares covered by the notice

Shares outstanding 143,424,157 shares Magnite, Inc. common stock outstanding as listed in the Form 144

Recent sale shares 30,550 shares of common stock Shares sold during the past three months on 08/26/2026

Recent sale proceeds $712,166.86 Total for 30,550 Magnite, Inc. shares sold on 08/26/2026

Approximate date of proposed sale 08/28/2026 Approximate sale date for 18,436 shares under the Form 144 notice

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 | 06/28/2021 | 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 | Morgan Stanley Smith Barney LLC ... | 18436 | 442464.00"

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 financial

"144: Securities To Be Sold"

FAQ

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

What does the Form 144 filing for MGNI by Sarah Patricia Harden disclose?

It discloses that director Sarah Patricia Harden filed notice to sell 18,436 shares of Magnite, Inc. common stock under Rule 144, with an aggregate market value of $442,464.00, through Morgan Stanley Smith Barney LLC on NASDAQ around 08/28/2026.

How many MGNI shares is Sarah Patricia Harden proposing to sell under this Form 144?

The notice covers a proposed sale of 18,436 shares of Magnite, Inc. common stock. These shares are listed as Restricted Stock to be sold under Rule 144 through Morgan Stanley Smith Barney LLC.

What is the aggregate market value of the MGNI shares in the Form 144 notice?

The filing states an aggregate market value of $442,464.00 for the 18,436 shares of Magnite, Inc. common stock covered by the Form 144 notice.

How many Magnite (MGNI) shares are outstanding according to this filing?

The Form 144 lists 143,424,157 shares of Magnite, Inc. common stock outstanding. This figure provides context for the company’s share base and is not the number of shares being sold.

What MGNI stock sales by Sarah Patricia Harden occurred in the past three months?

The filing reports that 30,550 shares of Magnite, Inc. common stock were sold on 08/26/2026 for total proceeds of $712,166.86, in addition to the proposed sale covered by the current notice.

Which broker is handling the proposed MGNI stock sale in this Form 144?

The proposed sale of 18,436 shares of Magnite, Inc. common stock is listed as being handled by Morgan Stanley Smith Barney LLC Executive Financial Services, located at 1 New York Plaza, New York.

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

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Available on EDGAR 08/28/2026 - 04:04 PM EDT Accepted by SEC EDGAR 08/28/2026 - 04:03 PM EDT 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	0001781873
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	SARAH PATRICIA HARDEN
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	Director

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	18436	442464.00	143424157	08/28/2026	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	06/28/2021	Restricted Stock	ISSUER			18436	06/28/2021	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
SARAH PATRICIA HARDEN 1250 Broadway, 9th Floor New York, NY 10001	Common	08/26/2026	30550	712166.86

144: Remarks and Signature

Remarks
Date of Notice	08/28/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	05/27/2026
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/ Sarah Patricia Harden
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)