13F-HR: White Mountains Discloses Q4 2025 Holdings

White Mountains Insurance Group Ltd. filed its Q4 2025 13F report, revealing significant holdings in MediaAlpha Inc. Class A and SPDR S&P 500 ETF Trust.

Summary

• White Mountains Insurance Group Ltd. submitted a 13F Holdings Report for the calendar quarter ended December 31, 2025.
• The total market value of reportable securities held was $261,929,551.
• The report details two holdings entries.
• A significant position of 17,856,614 shares in MEDIAALPHA INC CL A, valued at $231,243,151, is reported.
• An investment of 45,000 shares in SPDR S&P 500 ETF TR, valued at $30,686,400, is also disclosed.
• All reported holdings are under the sole investment and voting discretion of White Mountains Insurance Group Ltd.

Sentiment

Score: 7

Explanation: StockSavvy.ai views this as a routine, transparent disclosure of institutional holdings, providing clear insight into White Mountains' equity portfolio composition as of the reporting date. The significant concentration in MediaAlpha Inc. suggests a strong conviction in that specific company.

Positives

• Clear and transparent disclosure of all reportable equity holdings as required by SEC regulations.
• A substantial investment in MediaAlpha Inc. Class A, potentially signaling confidence in the company's future performance.
• Inclusion of the SPDR S&P 500 ETF Trust provides broad market exposure and diversification within the equity portfolio.

Negatives

• No specific negatives are inherent in a standard 13F filing itself, as it is a disclosure of past holdings rather than a performance report.

Risks

• Market volatility could impact the value of the equity holdings, particularly the significant position in MediaAlpha Inc.
• Concentration risk exists due to the large proportion of the portfolio invested in a single company, MediaAlpha Inc.
• General market risks are associated with investments in the SPDR S&P 500 ETF Trust, reflecting broader economic and market conditions.

Future Outlook

NA

Industry Context

StockSavvy.ai notes that 13F filings provide transparency into institutional investment strategies, offering insights into which companies are attracting significant capital from major players like White Mountains Insurance Group. The substantial holding in MediaAlpha Inc. suggests a belief in the growth potential of the ad-tech or digital media sector, while the SPDR S&P 500 ETF holding provides broad market exposure to the overall U.S. equity market.

Stakeholder Impact

• Shareholders of White Mountains Insurance Group Ltd. gain transparency into the company's equity investment strategy and portfolio composition.
• Shareholders of MediaAlpha Inc. may view White Mountains' significant stake as a vote of confidence, potentially influencing market sentiment.
• The broader market gains insight into institutional investment trends and the allocation strategies of major investment managers.

Key Dates

Keywords

13F, holdings, institutional investment, White Mountains Insurance Group, MediaAlpha, SPDR S&P 500 ETF, equity portfolio, investment disclosure