[SCHEDULE 13D/A] MediaAlpha, Inc. SEC Filing

Rhea-AI Filing Summary

White Mountains Insurance Group, Ltd. and its subsidiary WM Hinson (Bermuda) Ltd. report beneficial ownership of Class A common stock of MediaAlpha, Inc. The filing updates percentage ownership solely because the number of outstanding Class A shares changed per the issuer's disclosure. Together, the Reporting Persons are reported to beneficially own 17,856,614 Class A Shares, which the filing states represents approximately 31.68% of outstanding Class A shares based on the issuer's disclosed share count of 56,370,303 Class A Shares. White Mountains directly holds 900,000 Class A Shares and is the indirect owner of 16,956,614 Class A Shares held by WM Hinson.

The amendment clarifies that none of the Reporting Persons own Class B shares and explains certain shared voting/dispositive arrangements and disclaimers of beneficial ownership. The filing incorporates prior disclosures and restates Item 5 to reflect the current share counts and ownership percentages without reporting any new acquisitions or dispositions.

Positive

• Material disclosure of beneficial ownership: Reporting Persons report beneficial ownership of 17,856,614 Class A Shares (~31.68%).
• Clarifies basis for percentage change: The amendment states the change in percentage resulted solely from a change in the number of outstanding Class A shares disclosed by the issuer.
• Breakout of direct vs. indirect holdings: White Mountains directly holds 900,000 Class A Shares and indirectly holds 16,956,614 Class A Shares via WM Hinson.

Negative

• Concentrated ownership: A >30% position is significant and could affect control dynamics or prompt stakeholder concerns about influence.
• Ownership complexity: Shared voting power and multiple disclaimers in the filing create ambiguity about who ultimately controls voting or disposition of certain shares.
• Reliance on prior agreements: The filing references a Stockholders' Agreement and prior Schedule 13D disclosures, indicating that full implications depend on documents not restated in this amendment.

Insights

Financial Analyst

TL;DR: A large, disclosed stake (~31.7%) materially shifts the ownership profile and may affect governance dynamics.

The filing documents a material, concentrated position by White Mountains and its subsidiary totaling 17.86 million Class A shares (~31.68%) of MediaAlpha's Class A stock based on the issuer's disclosed share count. From a capital-markets view, this level of ownership is large enough to influence votes on routine corporate matters and to shape strategic outcomes, depending on alignment with other holders. The amendment states the percentage change is driven solely by the issuer's change in outstanding Class A shares rather than new purchases, and it reiterates shared voting arrangements and disclaimers that complicate a straightforward control assessment.

Corporate Governance Expert

TL;DR: Disclosure of a >30% stake is material for governance and should prompt review of shareholder agreements and voting arrangements.

The Schedule 13D/A provides transparent quantification of a substantial shareholder position: White Mountains (including WM Hinson) reports indirect and direct holdings totaling 17,856,614 Class A shares. The filing's emphasis on shared voting power and explicit disclaimers indicates complex governance relationships among Stockholders' Agreement parties. For boards and other investors, the key takeaways are the magnitude of the stake and the potential for coordinated voting influence, subject to the specific terms of the referenced Stockholders' Agreement and any related voting arrangements disclosed previously.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 5)

MediaAlpha, Inc.

(Name of Issuer)

Class A Common Stock, par value $0.01 per share

(Title of Class of Securities)

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)

08/08/2025

(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).

SCHEDULE 13D

CUSIP No. 58450V104

1

Name of reporting person

White Mountains Insurance Group, Ltd.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

BERMUDA

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 900,000.00
8	Shared Voting Power 16,956,614.00
9	Sole Dispositive Power 900,000.00
10	Shared Dispositive Power 16,956,614.00

11

Aggregate amount beneficially owned by each reporting person

17,856,614.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

31.7 %

14

Type of Reporting Person (See Instructions)

HC

SCHEDULE 13D

CUSIP No. 58450V104

1

Name of reporting person

WM Hinson (Bermuda) Ltd.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

BERMUDA

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 16,956,614.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 16,956,614.00

11

Aggregate amount beneficially owned by each reporting person

16,956,614.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

30.1 %

14

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13D

Item 1.	Security and Issuer
(a)	Title of Class of Securities: Class A Common Stock, par value $0.01 per share
(b)	Name of Issuer: MediaAlpha, Inc.
(c)	Address of Issuer's Principal Executive Offices: 700 South Flower Street, Suite 640, Los Angeles, CALIFORNIA , 90017.
Item 1 Comment: This Amendment No. 5 (this "Amendment No. 5") to the Schedule 13D filed with the Securities and Exchange Commission (the "Commission") on June 30, 2023 (as amended and supplemented from time to time, this "Schedule 13D") is being filed jointly by White Mountains Insurance Group, Ltd. ("White Mountains") and WM Hinson (Bermuda) Ltd. ("WM Hinson" and, together with White Mountains, the "Reporting Persons") with respect to the Class A Common Stock, par value $0.01 per share (the "Class A Shares"), of MediaAlpha, Inc., a Delaware corporation (the "Issuer") beneficially owned by the Reporting Persons. The purpose of this Amendment No. 5 is to report a change in the percentage of the Class A Shares beneficially owned by the Reporting Persons solely due to the change in the number of outstanding Class A Shares as disclosed in the Issuer's Form 10-Q filed with the Commission on August 6, 2025. Except as set forth below, all Items of this Schedule 13D remain unchanged. Capitalized terms used in this Amendment No. 5 and not otherwise defined shall have the respective meanings assigned to such terms in this Schedule 13D.
Item 5.	Interest in Securities of the Issuer
(a)	Item 5(a)-(b) is amended and restated as follows: The information set forth on the cover pages of this Amendment No. 5, and the information set forth or incorporated by reference in Items 2, 3, 4 and 6 of this Schedule 13D are hereby incorporated by reference in this Item 5(a)-(b). As of the date hereof, White Mountains directly holds 900,000 Class A Shares of the Issuer and is the indirect beneficial owner of 16,956,614 Class A Shares directly held by its wholly owned direct subsidiary, WM Hinson, as presented herein. None of the Reporting Persons beneficially owns any shares of Class B Common Stock, par value $0.01 per share ("Class B Shares"). The Class A Shares held by the Reporting Persons represent approximately 31.68% of the outstanding Class A Shares. As of the date hereof, and based on the knowledge of the Reporting Persons, the beneficial ownership of Class A Shares of the persons listed in Annex A is as follows: Steven Yi holds 2,030,232 Class A Shares and 46,166 Class B Shares, which results in Mr. Yi beneficially owning 2,174,158 Class A Shares, representing approximately 3.86% of the outstanding Class A Shares; Robert L. Seelig holds 9,000 Class A Shares, which results in Mr. Seelig beneficially owning 9,000 Class A Shares, representing approximately 0.02% of the outstanding Class A Shares; and John G. Sinkus holds 750 Class A Shares, which results in Mr. Sinkus beneficially owning 750 Class A Shares, representing less than 0.01% of the outstanding Class A Shares. The beneficial ownership calculations set forth herein assume the exchange of any Class B Shares beneficially owned, together with a corresponding number of Class B-1 Units, for an equal number of Class A Shares pursuant to the Exchange Agreement. The percentage calculations set forth herein are based on 56,370,303 Class A Shares issued and outstanding as of July 31, 2025, as reported in the Issuer's Form 10-Q filed with the Commission on August 6, 2025, and are calculated in accordance with Rule 13d-3(d)(1)(i) under the Exchange Act. In addition to the above, based solely on the information reported in the Schedule 13D filed by OBF Investments, LLC a Nevada limited liability company ("OBF"), and its Manager, Jason Heiling, on June 25, 2021, OBF holds 3,923,885 Class B Shares. OBF Investments is owned by trusts for the benefit of Mr. Yi and members of his family. Mr. Yi does not have any voting or dispositive control over the shares held by OBF. See the Schedule 13D filed by OBF and its Manager, Jason Heiling, on June 25, 2021, for additional information with respect to OBF. By virtue of the relationships described under Item 2 of this Schedule 13D, White Mountains may be deemed, for purposes of Rule 13d-3 under the Exchange Act, to share the power to vote or dispose, or to direct the voting or disposition of the Class A Shares directly held by WM Hinson. The filing of this Amendment No. 5 shall not be construed as an admission that any Reporting Person is the beneficial owner of any of the Class A Shares that such Reporting Person may be deemed to beneficially own. Without limiting the foregoing sentence, all of the Reporting Persons, other than with respect to Class A Shares directly held by such Reporting Person as described on each cover page to this Amendment No. 5, disclaim beneficial ownership of all Class A Shares reported in this Amendment No. 5. In addition, the filing of this Amendment No. 5 shall not be construed as an admission that any partner, member, director, officer or affiliate of any Reporting Person is the beneficial owner of any of the Class A Shares that such partner, member, director, officer or affiliate may be deemed to beneficially own. In addition, because of the relationships among White Mountains and WM Hinson, on the one hand, and the other Stockholders' Agreement Parties, on the other hand, as a result of the Stockholders Agreement, the Reporting Persons may be deemed, pursuant to Rules 13d-3 and 13d-5 under the Act, to beneficially own the Class A Shares, Class B Shares or Class B-1 Units held in aggregate by the other Stockholders' Agreement Parties. Notwithstanding the foregoing, the filing of this Amendment No. 5 shall not be construed as an admission that any Reporting Person is the beneficial owner of any of the Class A Shares, Class B Shares or Class B-1 Units that such Reporting Person may be deemed to beneficially own. Further, each of the Reporting Persons disclaims membership in a group with each other Stockholders' Agreement Party.
(b)	Same as (a) above.

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.

White Mountains Insurance Group, Ltd.

Signature:	/s/ Robert L. Seelig
Name/Title:	Robert L. Seelig - Executive Vice President and General Counsel
Date:	08/08/2025

WM Hinson (Bermuda) Ltd.

Signature:	/s/ John G. Sinkus
Name/Title:	John G. Sinkus - Vice President
Date:	08/08/2025

FAQ

How many Class A shares does White Mountains/WM Hinson beneficially own in MediaAlpha (MAX)?

The filing reports that the Reporting Persons beneficially own 17,856,614 Class A Shares in aggregate, representing approximately 31.68% of outstanding Class A shares.

What portion of the stake is directly held by White Mountains versus WM Hinson?

White Mountains directly holds 900,000 Class A Shares; WM Hinson directly holds 16,956,614 Class A Shares (indirectly owned by White Mountains).

Does the filing show any ownership of Class B shares by the Reporting Persons?

No. The filing states that none of the Reporting Persons beneficially own any Class B Common Stock.

Why did the percentage ownership change in this amendment?

The amendment states the change in the reported percentage was solely due to a change in the number of outstanding Class A shares disclosed by the issuer, not because of new purchases or sales by the Reporting Persons.

Does White Mountains share voting or dispositive power over the WM Hinson-held shares?

The filing states that, by virtue of relationships described in Item 2 and the Stockholders' Agreement, White Mountains may be deemed to share the power to vote or dispose of the Class A shares directly held by WM Hinson.