Magnite officer plans $763K stock sale

Rhea-AI Filing Summary

MAGNITE, INC. (MGNI) received a Rule 144 notice that officer Katheryn Evans plans to sell up to 32,285 shares of common stock, with an indicated aggregate market value of $762,870.57, through Morgan Stanley Smith Barney LLC, with the sale expected on or about September 8, 2026 on NASDAQ.

The shares consist of stock acquired via a stock option exercise (13,546 shares) and restricted stock grants from 2023 (11,848 shares) and 2020 (6,891 shares). Evans previously sold 20,000 shares for $480,000.00 on August 6, 2026.

Key Figures

Planned shares to be sold: 32,285 shares Aggregate market value of planned sale: $762,870.57 Shares outstanding: 143,424,157 shares +5 more

8 metrics

Planned shares to be sold 32,285 shares Common stock to be sold under Rule 144 by Katheryn Evans

Aggregate market value of planned sale $762,870.57 Estimated value of 32,285 shares of MAGNITE, INC. common stock

Shares outstanding 143,424,157 shares MAGNITE, INC. common stock shares outstanding referenced in the notice

Recent shares sold 20,000 shares Shares sold by Katheryn Evans on August 6, 2026

Proceeds from recent sale $480,000.00 Total proceeds from the August 6, 2026 sale of 20,000 shares

Stock option exercise shares 13,546 shares Shares underlying stock option exercise dated September 8, 2026

Restricted stock (2023 grant) 11,848 shares Restricted stock acquired February 15, 2023

Restricted stock (2020 grant) 6,891 shares Restricted stock acquired April 29, 2020

Key Terms

Rule 144, Restricted Stock, Stock Option Exercise, Aggregate market value

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 | 02/15/2023 | 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.

Stock Option Exercise financial

"Common | 09/08/2026 | Stock Option Exercise | ISSUER"

A stock option exercise is the act of using a previously granted right to buy shares of a company's stock at a specific, predetermined price by paying that price and receiving the shares. It matters to investors because exercising changes who owns the shares (which can dilute existing ownership), can trigger taxable events and shift potential gains or losses, and affects voting power and the company’s outstanding share count—like turning a voucher into an actual product that becomes part of circulating supply.

Aggregate market value financial

"Common | Morgan Stanley Smith Barney LLC ... | 32285 | 762870.57"

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

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

The filing discloses that officer Katheryn Evans plans to sell up to 32,285 shares of MAGNITE, INC. common stock under Rule 144, with an aggregate market value of about $762,870.57, through Morgan Stanley Smith Barney LLC on or about September 8, 2026.

How many MGNI shares is Katheryn Evans planning to sell under Rule 144?

Katheryn Evans plans to sell up to 32,285 shares of MAGNITE, INC. common stock. The notice lists these shares with an aggregate market value of $762,870.57 and an expected sale date of September 8, 2026 on NASDAQ.

What is the source of the MGNI shares covered by this Form 144?

The 32,285 MAGNITE, INC. shares come from a stock option exercise on September 8, 2026 for 13,546 shares, and restricted stock awards dated February 15, 2023 for 11,848 shares and April 29, 2020 for 6,891 shares.

Were there recent MGNI share sales by Katheryn Evans before this notice?

Yes. The filing reports that Katheryn Evans sold 20,000 shares of MAGNITE, INC. common stock on August 6, 2026 for total proceeds of $480,000.00 during the three months preceding the notice.

What percentage of MGNI shares outstanding does the planned Rule 144 sale represent?

The company reports 143,424,157 shares of MAGNITE, INC. common stock outstanding. The planned sale covers 32,285 shares, with the sale to be made on or about September 8, 2026 on NASDAQ.

Which broker is handling the planned MGNI share sale under Rule 144?

The planned sale of 32,285 MAGNITE, INC. shares will be handled by Morgan Stanley Smith Barney LLC Executive Financial Services, located at 1 New York Plaza, 8th Floor, New York, NY 10004, as listed in the Form 144 filing.

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

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Available on EDGAR 09/08/2026 - 04:09 PM Accepted by SEC EDGAR 09/08/2026 - 04:09 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	0001700262
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	KATHERYN EVANS
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	32285	762870.57	143424157	09/08/2026	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	09/08/2026	Stock Option Exercise	ISSUER			13546	09/08/2026	Cash
Common	02/15/2023	Restricted Stock	ISSUER			11848	02/15/2023	Not Applicable
Common	04/29/2020	Restricted Stock	ISSUER			6891	04/29/2020	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
KATHERYN EVANS 1250 Broadway, 9th Floor New York, NY 10001	Common	08/06/2026	20000	480000.00

144: Remarks and Signature

Remarks
Date of Notice	09/08/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	06/08/2026
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/ Katheryn Evans
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)