SCHEDULE: White Mountains Adjusts MediaAlpha Stake Disclosure

White Mountains Insurance Group updates its beneficial ownership of MediaAlpha, Inc. following changes in the issuer's outstanding share count.

Summary

• White Mountains Insurance Group and its subsidiary, WM Hinson (Bermuda) Ltd., report beneficial ownership of 17,856,614 Class A shares of MediaAlpha, Inc.
• The reported stake represents 33.03% of MediaAlpha's total outstanding Class A common stock.
• The filing reflects a change in percentage ownership due to the updated number of outstanding shares reported in MediaAlpha's Form 10-Q on April 29, 2026.
• The reporting persons confirm they have no current intent to replace two board designees who recently departed.

Sentiment

Score: 5

Explanation: StockSavvy.ai views this as a neutral administrative filing; while the ownership stake remains stable, the loss of board representation is a qualitative change that warrants monitoring.

Positives

• Maintains a significant 33.03% ownership stake, indicating continued long-term interest in the issuer.

Negatives

• Loss of two board designees, Jennifer Moyer and Christopher Delehanty, who resigned or chose not to stand for re-election.
• Reporting persons have no current intent to appoint new designees to the board, potentially reducing their direct influence on corporate governance.

Risks

• Potential reduction in oversight or influence over MediaAlpha's strategic direction due to the loss of board representation.
• Market volatility associated with the significant concentration of ownership held by the reporting persons.

Future Outlook

The reporting persons have stated they have no present intent to designate directors to fill the vacancies left by the departures of Jennifer Moyer and Christopher Delehanty.

Management Comments

• The reporting persons have no present intent to designate directors to fill the vacancies left by the Notifications.

Industry Context

StockSavvy.ai notes that the reduction in board representation by a major institutional shareholder like White Mountains often signals a shift in the relationship between the investor and the issuer, potentially moving toward a more passive investment stance.

Comparison to Industry Standards

• The 33% ownership stake remains a significant block, consistent with long-term institutional holding patterns in the financial technology and insurance marketing sectors.
• The departure of board designees without immediate replacement is a notable deviation from standard active-investor governance practices.

Management Changes

Corporate Governance

Legal Proceedings

• None mentioned.

Related Party Transactions

• The filing references the Stockholders Agreement and the Exchange Agreement, which govern the relationship between the reporting persons and other stockholders.

Stakeholder Impact

• Shareholders should note the reduction in board representation by a major institutional investor.
• The stability of the 33% stake suggests the reporting person remains a committed long-term holder.

Next Steps

• Continued monitoring of MediaAlpha's board composition.
• Future filings if ownership percentages change significantly.

Key Dates

Keywords

MediaAlpha, White Mountains Insurance Group, Schedule 13D, Beneficial Ownership, Corporate Governance, Class A Common Stock