SCHEDULE 13D/A

MediaAlpha Inc

Class A Common Stock, par value $0.01 per share · CUSIP: 58450V104

Event date: 2025-08-08

Reporting persons may disclose overlapping interests. Their amounts are shown individually and are not added into a filing total.

Filing-level shares

Unavailable

Percent of class

Unavailable

• White Mountains Insurance Group, Ltd.Reported CIK 0000776867

  Shares: 17,856,614 · Class: 31.7%

• WM Hinson (Bermuda) Ltd.Reported CIK 0001979065

  Shares: 16,956,614 · Class: 30.1%

Amounts are as disclosed in this filing. Schedule type alone does not establish investment intent.