White Mountains reports lower book value, plans MediaAlpha share sale

White Mountains  reported book value per share of $2,243 at September 30, 2026, down 1% for the quarter and up 3% for the first nine months, including dividends. Higher interest rates and a decline in MediaAlpha’s share price offset positive operating results.

The company recorded a comprehensive loss attributable to common shareholders of $39 million, compared with comprehensive income of $114 million a year earlier. Its MediaAlpha investment generated $54 million in unrealized losses as the stock fell 24% during the quarter.

On November 4, White Mountains agreed to sell 5.5 million MediaAlpha shares for $13.90 per share, or approximately $76.5 million. Following the sale, it would retain 12.4 million shares, representing a 21% ownership interest.

Ark reported a combined ratio of 75%, compared with 76% a year earlier. Gross written premiums increased to $386 million from $366 million, while pretax income declined to $64 million from $97 million as investment results weakened. Ark recorded $10 million in quarterly losses related to the war in Iran, bringing its nine-month total to $52 million.

Distinguished Programs generated $159 million in managed premiums, $55 million in commission and fee revenue, and a $13 million pretax loss. Trailing 12-month managed premiums reached $625 million, supported by growth in environmental and surety programs.

White Mountains ended the quarter with approximately $800 million in undeployed capital.