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MediaAlpha: White Mountains reports about 35.08% stake

Robert L. Seelig, Executive Vice President and General Counsel, reported beneficial ownership of 10,000 Class A shares; Vice President John G. Sinkus reported 750.

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Form Type
SCHEDULE 13D/A

Rhea-AI Filing Summary

MediaAlpha, Inc. (MAX) is the issuer in Amendment No. 7 jointly filed by White Mountains Insurance Group, Ltd. and WM Hinson (Bermuda) Ltd., which updates their reported Class A ownership percentages solely because the outstanding share count changed. White Mountains reported beneficial ownership of 17,856,614 Class A shares, or approximately 35.08%; it directly holds 900,000 shares and indirectly beneficially owns 16,956,614 shares directly held by its wholly owned direct subsidiary, WM Hinson. WM Hinson separately reported beneficial ownership of 16,956,614 shares, or 33.3%.

The percentages use 50,903,805 Class A shares outstanding as of October 26, 2026. Both reporting persons state that they beneficially own no Class B shares.

Filing Explained

This amendment says the Stockholders’ Agreement relationships may cause White Mountains and WM Hinson to be deemed beneficial owners of securities held by other agreement parties, while disclaiming that beneficial ownership and membership in a group with those parties.

White Mountains beneficial ownership 17,856,614 Class A shares Reported aggregate amount
White Mountains ownership percentage Approximately 35.08% Of outstanding Class A shares
White Mountains directly held shares 900,000 Class A shares Direct holding
WM Hinson beneficial ownership 16,956,614 Class A shares Shares directly held by WM Hinson
WM Hinson ownership percentage 33.3% Of outstanding Class A shares
Class A shares outstanding 50,903,805 shares As of October 26, 2026
Robert L. Seelig, Executive Vice President and General Counsel, beneficial ownership 10,000 Class A shares Individual ownership stated in the amendment
John G. Sinkus, Vice President, beneficial ownership 750 Class A shares Individual ownership stated in the amendment
beneficial ownership regulatory
"Aggregate amount beneficially owned"
Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.
shared voting power regulatory
"Shared Voting Power"
Shared voting power occurs when two or more parties jointly have the right to vote or decide how a block of company shares is cast, like co-owners who must agree before moving a piece of furniture. Investors care because who controls voting rights affects board elections, major corporate decisions and takeover outcomes, and shared control can alter regulatory disclosures and the practical influence any holder has over a company’s direction and value.
shared dispositive power regulatory
"Shared Dispositive Power"
Class B-1 Units financial
"together with a corresponding number of Class B-1 Units"

FAQ

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

How many MediaAlpha (MAX) Class A shares does White Mountains report beneficially owning?

White Mountains reported beneficial ownership of 17,856,614 Class A shares, approximately 35.08% of outstanding Class A shares. It directly held 900,000 shares; its wholly owned direct subsidiary, WM Hinson, directly held 16,956,614 shares.

Why did White Mountains' reported MediaAlpha (MAX) ownership percentage change?

The amendment says the percentage changed solely because the outstanding Class A share count changed, as disclosed in MediaAlpha's Form 10-Q filed October 28, 2026. The calculation uses 50,903,805 Class A shares outstanding as of October 26, 2026.

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

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58450V104

(CUSIP Number)
Robert L. Seelig, Esq.
23 South Main Street, Suite 3B,
Hanover, NH, 03755
(603) 640-2200

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)
10/28/2026

(Date of Event Which Requires Filing of This Statement)


If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).




schemaVersion:


SCHEDULE 13D






SCHEDULE 13D






SCHEDULE 13D


White Mountains Insurance Group, Ltd.
Signature:/s/ Robert L. Seelig
Name/Title:Robert L. Seelig / Executive Vice President and General Counsel
Date:10/30/2026
WM HINSON (BERMUDA) LTD.
Signature:/s/ John G. Sinkus
Name/Title:John G. Sinkus / Vice President
Date:10/30/2026

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