Magnite (NASDAQ: MGNI) insider Barrett plans sale of 293,968 shares after option exercise

Rhea-AI Filing Summary

Magnite, Inc. (MGNI) has a notice from Michael G. Barrett covering a proposed sale of up to 293,968 shares of common stock, to be effected through Morgan Stanley Smith Barney LLC’s Executive Financial Services, following a stock option exercise, with a proposed sale date of August 6, 2026 on NASDAQ.

The filing also lists prior sales in the last three months: 38,596 shares for $785,509.65 on July 15, 2026; 75,000 shares for $1,462,500.00 on June 29, 2026; 100,000 shares for $1,750,000.00 on June 16, 2026; and 178,596 shares for $2,962,061.65 on June 15, 2026.

Key Figures

Proposed shares to be sold: 293,968 shares Aggregate market value of proposed sale: $6,678,952.96 Sale on 07/15/2026: 38,596 shares for $785,509.65 +3 more

6 metrics

Proposed shares to be sold 293,968 shares Common stock proposed for sale on 08/06/2026

Aggregate market value of proposed sale $6,678,952.96 Value associated with 293,968 shares of common stock

Sale on 07/15/2026 38,596 shares for $785,509.65 Common stock sold during past 3 months

Sale on 06/29/2026 75,000 shares for $1,462,500.00 Common stock sold during past 3 months

Sale on 06/16/2026 100,000 shares for $1,750,000.00 Common stock sold during past 3 months

Sale on 06/15/2026 178,596 shares for $2,962,061.65 Common stock sold during past 3 months

Key Terms

Form 144, Stock Option Exercise, Executive Financial Services

3 terms

Form 144 regulatory

"144: Securities Sold During The Past 3 Months"

Form 144 is a document that investors must file with the government when they plan to sell a large number of shares of a company's stock. It helps ensure transparency so everyone knows how many shares are being sold and when, which can impact the stock's price.

Stock Option Exercise financial

"Common | 08/06/2026 | 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.

Executive Financial Services financial

"Morgan Stanley Smith Barney LLC Executive Financial Services 1 New York Plaza"

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Available on EDGAR 08/06/2026 - 04:02 PM Accepted by SEC EDGAR 08/06/2026 - 04:01 PM Learn about SEC filing dates

FAQ

What does the MGNI Form 144 filed by Michael G. Barrett disclose?

It discloses a proposed sale of up to 293,968 shares of Magnite common stock, to be sold through Morgan Stanley Smith Barney LLC Executive Financial Services following a stock option exercise, with a proposed sale date of August 6, 2026 on NASDAQ.

How many MGNI shares is Michael G. Barrett planning to sell under this Form 144?

Michael G. Barrett is planning a proposed sale of up to 293,968 shares of Magnite common stock. The filing lists these shares as arising from a stock option exercise with sales proposed for August 6, 2026 on NASDAQ.

What prior MGNI stock sales by Michael G. Barrett are listed in the last 3 months?

The filing lists four prior sales: 38,596 shares for $785,509.65 on July 15, 2026; 75,000 shares for $1,462,500.00 on June 29, 2026; 100,000 shares for $1,750,000.00 on June 16, 2026; and 178,596 shares for $2,962,061.65 on June 15, 2026.

Through which broker are the proposed MGNI share sales by Michael G. Barrett to be executed?

The proposed sale of up to 293,968 shares is to be executed through Morgan Stanley Smith Barney LLC Executive Financial Services, located at 1 New York Plaza, 8th Floor, New York, NY 10004, with trading on NASDAQ as disclosed.

What is the aggregate market value noted for the proposed MGNI share sale?

The Form 144 notes an aggregate market value of $6,678,952.96 associated with the 293,968 shares of Magnite common stock covered by the proposed sale, with the securities listed for trading on NASDAQ on August 6, 2026.

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
Filer CCC
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer

SEC File Number

Address of Issuer

Phone

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

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

Relationship to Issuer

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	293968	6678952.96	143424157	08/06/2026	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	08/06/2026	Stock Option Exercise	Issuer			293968	08/06/2026	Cash

* 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
MICHAEL G BARRETT 1250 Broadway, 9th Floor New York, NY 10001	Common	07/15/2026	38596	785509.65
MICHAEL G BARRETT 1250 Broadway, 9th Floor New York, NY 10001	Common	06/29/2026	75000	1462500.00
MICHAEL G BARRETT 1250 Broadway, 9th Floor New York, NY 10001	Common	06/16/2026	100000	1750000.00
MICHAEL G BARRETT 1250 Broadway, 9th Floor New York, NY 10001	Common	06/15/2026	178596	2962061.65

144: Remarks and Signature

Remarks

Date of Notice

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

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

ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)