FMR LLC Reports 3.1% Stake in Magnite

Magnite Inc. ownership filing reports that FMR LLC (and Abigail P. Johnson via power of attorney) beneficially owns 4,507,418.57 shares of common stock, representing 3.1% of the class.

Rhea-AI Filing Summary

Magnite Inc. ownership filing reports that FMR LLC (and Abigail P. Johnson via power of attorney) beneficially owns 4,507,418.57 shares of common stock, representing 3.1% of the class. The filing is an amendment (No. 3) to a Schedule 13G/A and lists voting and dispositive powers.

The cover shows sole dispositive power of 4,507,418.57 shares and sole voting power of 4,499,424. The response states this is ownership of 5 percent or less of the class and names FMR LLC’s Boston address.

Insights

Institutional Ownership Analyst

FMR LLC reports a passive stake of 3.1 in Magnite (common stock).

FMR LLC is disclosed as beneficial owner of 4,507,418.57 shares with sole dispositive power and nearly identical sole voting power reported on the cover. The filing is an amended Schedule 13G/A, consistent with passive investor reporting.

Key dependencies include whether holdings change in later filings; subsequent amendments or Form 13D/13G updates would alter the ownership picture and potential filing status.

Compliance & Filings Specialist

Amendment No. 3 updates beneficial ownership and confirms power-of-attorney signatories.

The schedule notes a power of attorney effective April 13, 2026 and signatures dated May 5, 2026. Exhibit references include Exhibit 24 and Exhibit 99 concerning the 13d-1(k)(1) agreement.

Filing-classification language states "Ownership of 5 percent or less of a class," which governs reporting cadence and public disclosures under applicable rules.

Key Figures

Beneficial ownership: 4,507,418.57 shares Percent of class: 3.1% Sole voting power: 4,499,424 shares +3 more

6 metrics

Beneficial ownership 4,507,418.57 shares Amount beneficially owned as reported on Schedule 13G/A

Percent of class 3.1% Percent of common stock class reported in Item 4

Sole voting power 4,499,424 shares Sole voting power shown on the cover page

Sole dispositive power 4,507,418.57 shares Sole power to dispose as reported on the cover page

Power of attorney effective April 13, 2026 Effective date referenced for power of attorney

Signature date May 5, 2026 Date of signature for the amendment

Key Terms

Schedule 13G/A, beneficially owned, dispositive power, power of attorney

4 terms

Schedule 13G/A regulatory

"Amendment No. 3 ) MAGNITE INC COMMON STOCK"

A Schedule 13G/A is an amended public filing with the U.S. securities regulator that updates a previous Schedule 13G, disclosing when an individual or group holds a substantial (typically over 5%) stake in a company and is claiming a passive, non‑controlling intent. Investors monitor these updates because rising or falling holdings can signal changing confidence, potential future moves, or shifts in voting power — like watching a public ledger where large shareholders quietly adjust their positions.

beneficially owned financial

"Amount beneficially owned: 4507418.57"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

dispositive power regulatory

"Sole Dispositive Power 4,507,418.57"

Dispositive power is the authority to decide the final outcome of an asset, legal claim, contract, or corporate action — in effect the power to dispose of or resolve something. For investors it matters because whoever holds that authority can determine who gets paid, who controls an asset or vote, and how risks and returns are allocated; think of it like holding the key that lets you lock in the winner or loser in a deal.

power of attorney legal

"Power of Attorney effective as of April 13, 2026"

A power of attorney is a legal document that allows one person to make decisions and act on behalf of another person, often in financial or legal matters. It’s like giving someone a trusted helper or agent the authority to handle important tasks if you are unable to do so yourself. This matters to investors because it can impact how their assets are managed or transferred if they become unable to oversee their affairs.

FAQ

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

What stake does FMR LLC report in MAGNITE Inc (MGNI)?

FMR LLC reports beneficial ownership of 4,507,418.57 shares, equal to 3.1% of common stock. The Schedule 13G/A amendment lists sole dispositive power of the same share amount and sole voting power of 4,499,424.

Does this filing indicate active control or passive ownership for MGNI?

This Schedule 13G/A indicates passive ownership, described as "Ownership of 5 percent or less of a class." The filing classifies the position consistent with passive investor reporting rather than an activist or control filing.

Who signed the amendment for FMR LLC and what authority is cited?

The filing is signed by Richard Bourgelas under a power of attorney and references a power of attorney effective April 13, 2026. Signatures are dated May 5, 2026, and Exhibit 24 is incorporated by reference.

How much voting power does FMR LLC have in MGNI?

FMR LLC reports sole voting power of 4,499,424 shares. The filing separately reports sole dispositive power of 4,507,418.57 shares and shared powers as 0.00 as shown on the cover.

Does the filing identify other parties with economic rights to the shares?

The filing states that one or more other persons are known to have rights to dividends or sale proceeds, and no single other person holds more than 5% of the outstanding common stock. Beneficiaries of funds are not listed individually.

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

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Accepted by SEC EDGAR 05/06/2026 - 11:30 AM EDT Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 3)

MAGNITE INC

(Name of Issuer)

COMMON STOCK

(Title of Class of Securities)

55955D100

(CUSIP Number)

03/31/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 55955D100

1

Names of Reporting Persons

FMR LLC

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 4,499,424.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 4,507,418.57
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

4,507,418.57

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

3.1 %

12

Type of Reporting Person (See Instructions)

HC

SCHEDULE 13G

CUSIP Number(s): 55955D100

1

Names of Reporting Persons

Abigail P. Johnson

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 4,507,418.57
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

4,507,418.57

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

3.1 %

12

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: MAGNITE INC
(b)	Address of issuer's principal executive offices: 1250 BROADWAY, 15TH FLOOR,NEW YORK,NY,USA,10001
Item 2.
(a)	Name of person filing: FMR LLC
(b)	Address or principal business office or, if none, residence: 245 Summer Street, Boston, Massachusetts 02210
(c)	Citizenship: Not applicable
(d)	Title of class of securities: COMMON STOCK
(e)	CUSIP No.: 55955D100
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 4507418.57
(b)	Percent of class: 3.1 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: Please see the responses to Items 5 and 6 on the cover page.
	(ii) Shared power to vote or to direct the vote: 0.00
	(iii) Sole power to dispose or to direct the disposition of: 4507418.57
	(iv) Shared power to dispose or to direct the disposition of: 0.00
Item 5.	Ownership of 5 Percent or Less of a Class.
	Ownership of 5 percent or less of a class
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required. One or more other persons are known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the COMMON STOCK of MAGNITE INC. No one other person's interest in the COMMON STOCK of MAGNITE INC is more than five percent of the total outstanding COMMON STOCK.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	If a parent holding company has filed this schedule, pursuant to Rule 13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary. See attached Exhibit 99.
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

FMR LLC

Signature:	Richard Bourgelas
Name/Title:	Duly authorized under Power of Attorney effective as of April 13, 2026, by and on behalf of FMR LLC and its direct and indirect subsidiaries*
Date:	05/05/2026

Abigail P. Johnson

Signature:	Richard Bourgelas
Name/Title:	Duly authorized under Power of Attorney effective as of April 13, 2026, by and on behalf of Abigail P. Johnson*
Date:	05/05/2026

Comments accompanying signature: *This power of attorney is incorporated herein by reference to Exhibit 24 to the Schedule 13G filed by FMR LLC on April 29,2026, accession number: 0000315066-26-000738.

Exhibit Information

Please see Exhibit 99 for 13d-1(k) (1) agreement.