Magnite director plans $476K company stock sale

Rhea-AI Filing Summary

MAGNITE, INC. (MGNI) director Paul Caine filed a notice of proposed sale under Rule 144 for up to 20,000 shares of common stock through Morgan Stanley Smith Barney LLC. The shares were acquired upon vesting of restricted stock units between June 1, 2016 and June 1, 2018, and prior 10b5-1 plan sales over the past three months are also listed.

Key Figures

Planned Rule 144 sale: 20,000 shares of common stock Aggregate market value of planned sale: $475,600 Sale on September 10, 2026: 5,000 shares for $117,643 +3 more

6 metrics

Planned Rule 144 sale 20,000 shares of common stock Maximum shares to be sold for Paul Caine’s account

Aggregate market value of planned sale $475,600 Value associated with the 20,000 shares to be sold

Sale on September 10, 2026 5,000 shares for $117,643 10b5-1 sale of Magnite common stock disclosed for past 3 months

Sale on August 14, 2026 7,500 shares for $187,500 10b5-1 sale of Magnite common stock disclosed for past 3 months

Sale on August 10, 2026 5,000 shares for $121,740 10b5-1 sale of Magnite common stock disclosed for past 3 months

Sale on July 10, 2026 5,000 shares for $103,185 10b5-1 sale of Magnite common stock disclosed for past 3 months

Key Terms

Rule 144, restricted stock units, 10b5-1

3 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 units financial

"The securities to be sold were acquired upon the vesting of 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.

10b5-1 regulatory

"10b5-1 Sales for PAUL CAINE 1250 Broadway, 9th Floor New York NY 10001"

A 10b5-1 plan is a pre-set schedule that lets company insiders buy or sell shares according to written instructions made when they do not possess material, nonpublic information. Think of it as a timed automatic payment for stock trades: it helps insiders avoid accusations of trading on secret information and gives outside investors a clearer signal about whether sales are routine or potentially informative about the company’s prospects.

FAQ

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

How many MGNI shares does Paul Caine plan to sell under this Form 144?

Paul Caine filed to potentially sell 20,000 shares of Magnite, Inc. common stock under Rule 144. These shares are to be sold through Morgan Stanley Smith Barney LLC Executive Financial Services, as disclosed in the notice.

What is the aggregate market value of the MGNI shares Paul Caine plans to sell?

The notice states an aggregate market value of $475,600 for the 20,000 shares of Magnite, Inc. common stock that Paul Caine may sell under Rule 144.

How were the MGNI shares that Paul Caine plans to sell originally acquired?

The shares to be sold were acquired upon the vesting of restricted stock units during the period from June 1, 2016 through June 1, 2018, according to the remarks in the notice.

What MGNI share sales by Paul Caine in the last three months are disclosed?

Disclosed 10b5-1 plan sales include: 5,000 shares on September 10, 2026 for $117,643; 7,500 shares on August 14, 2026 for $187,500; 5,000 shares on August 10, 2026 for $121,740; and 5,000 shares on July 10, 2026 for $103,185.

Is Paul Caine a director or officer of MAGNITE, INC. (MGNI)?

Yes. The notice identifies Paul Caine as a Director of MAGNITE, INC., and the Form 144 relates to sales of the company’s common stock for his account.

Through which broker will the proposed MGNI share sale be executed?

The proposed sale of up to 20,000 shares of Magnite, Inc. common stock for Paul Caine’s account is listed with Morgan Stanley Smith Barney LLC Executive Financial Services, located at 1 New York Plaza, 8th Floor, New York, NY 10004.

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

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Available on EDGAR 09/17/2026 - 04:57 PM Accepted by SEC EDGAR 09/17/2026 - 04:57 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	0001411765
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	PAUL CAINE
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	20000	475600.00	143424157	09/17/2026	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	06/01/2016	Restricted Stock Units	Issuer			20000	06/01/2016	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 PAUL CAINE 1250 Broadway, 9th Floor New York NY 10001	Common	09/10/2026	5000	117643.00
10b5-1 Sales for PAUL CAINE 1250 Broadway, 9th Floor New York NY 10001	Common	08/14/2026	7500	187500.00
10b5-1 Sales for PAUL CAINE 1250 Broadway, 9th Floor New York NY 10001	Common	08/10/2026	5000	121740.00
10b5-1 Sales for PAUL CAINE 1250 Broadway, 9th Floor New York NY 10001	Common	07/10/2026	5000	103185.00

144: Remarks and Signature

Remarks	The securities to be sold were acquired upon the vesting of restricted stock units during the period of 6/1/2016 through 6/1/2018
Date of Notice	09/17/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	08/20/2025
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/ Paul Caine
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)