[SCHEDULE 13G] MAGNITE, INC. Passive Investment Disclosure (>5%)

Rhea-AI Filing Summary

Magnite Inc reported that Vanguard Portfolio Management beneficially owns 7,849,870 shares of common stock, representing 5.43% of the class, as disclosed on a Schedule 13G. The filing shows sole voting power of 123,665 shares and sole dispositive power over 7,849,870 shares.

Insights

Institutional Ownership Analyst

Vanguard reports a >5% passive stake in Magnite.

Vanguard Portfolio Management discloses beneficial ownership of 7,849,870 shares (5.43% of the class) on a Schedule 13G filing, consistent with passive institutional reporting. The filing lists voting and dispositive powers, indicating day-to-day control rests with Vanguard's management of client accounts.

Catalysts to watch include future amendments if ownership or voting status changes; subsequent filings would show any moves above or below the 5% threshold.

Securities Compliance Counsel

Schedule 13G signals passive status under SEC rules.

The filing structure and signature indicate reporting under the beneficial owner rules for institutional investors; the cover text references SEC Release No. 34-39538 and affiliated Vanguard entities. Ownership is reported as held on behalf of funds/clients rather than direct proprietary ownership.

Compliance observations: any change to active intent or increases beyond thresholds should prompt a Form 13D or amendment per SEC requirements.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

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

Vanguard Portfolio Management

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

PENNSYLVANIA

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 123,665.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 7,849,870.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

7,849,870.00

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)

5.43 %

12

Type of Reporting Person (See Instructions)

IA

Comment for Type of Reporting Person: In accordance with SEC Release No. 34-39538 (January 12, 1998), this Schedule 13G reflects the securities beneficially owned, or deemed to be beneficially owned, by Vanguard Portfolio Management LLC and the following affiliates of Vanguard Portfolio Management LLC or business divisions of such affiliates: Vanguard Fiduciary Trust Company and Vanguard Global Advisers, LLC. This Schedule 13G includes securities held by Vanguard funds, or sleeves thereof, over which Vanguard Portfolio Management LLC exercises dispositive power, in addition to securities held by clients over which the affiliates or business divisions of such affiliates indicated above exercise dispositive and/or voting power. This Schedule 13G does not include securities, if any, beneficially owned by other subsidiaries or affiliates of Vanguard Portfolio Management LLC, or business divisions of such subsidiaries whose ownership of securities is disaggregated from that of the reporting business unit in accordance with such release.

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, 10001
Item 2.
(a)	Name of person filing: Vanguard Portfolio Management
(b)	Address or principal business office or, if none, residence: 100 Vanguard Blvd,, Malvern, PA, 19355
(c)	Citizenship: PA
(d)	Title of class of securities: Common Stock
(e)	CUSIP Number(s): 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: 7849870
(b)	Percent of class: 5.43 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 123665
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 7849870
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
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. Vanguard Portfolio Management, including investment companies registered under the Investment Company Act of 1940 and other managed accounts, have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the securities reported herein.No one other person's interest in the securities reported herein is more than 5%.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
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.

Vanguard Portfolio Management

Signature:	Ashley Grim
Name/Title:	Head of Global Fund Administration
Date:	04/29/2026

FAQ

How many Magnite (MGNI) shares does Vanguard Portfolio Management report owning?

Vanguard reports beneficial ownership of 7,849,870 shares. The Schedule 13G lists this as 5.43% of the class and shows sole dispositive power over the 7,849,870 shares and sole voting power for 123,665 shares.

What does the 5.43% ownership in MGNI imply about Vanguard's intent?

The filing is a Schedule 13G, which generally indicates passive ownership. The text references institutional reporting and affiliated Vanguard entities, implying holdings are managed for clients; it does not state activist or control intent in this excerpt.

Who at Vanguard signed the Magnite Schedule 13G and when was it filed?

The filing is signed by Ashley Grim, Head of Global Fund Administration. The signature block shows the date 04/29/2026, which is the reported execution date on the provided excerpt.

What voting and dispositive powers does Vanguard report for MGNI shares?

Vanguard reports sole voting power for 123,665 shares and sole dispositive power for 7,849,870 shares. Shared voting and dispositive powers are reported as zero in the provided Schedule 13G excerpt.