White Mountains Insurance Group — Third Quarter 2026 Earnings Summary

White Mountains Insurance Group reported book value per share of $2,243 as of September 30, 2026, reflecting a 1% decrease for the quarter and a 3% increase for the first nine months. Comprehensive income attributable to common shareholders was a loss of $39 million in the third quarter, primarily driven by $54 million in unrealized investment losses from the MediaAlpha portfolio and higher interest rates affecting fixed income valuations. Operating segments showed mixed results, with Ark achieving a 75% combined ratio and strong tangible book value growth, while Kudu and HG Global faced headwinds from rising interest rates impacting their investment portfolios.