White Mountains swings to Q3 loss on MediaAlpha stake decline

White Mountains (WTM) posted a loss in the third quarter of 2026, a sharp reversal from a profit a year earlier.

Shares were little changed at 10:15 a.m. ET, from a $2,376.30 close.

The loss was $17.71 per share, against the $34.34 consensus estimate.

Book value per share fell 1% in the quarter to $2,243 as of September 30, including dividends.

Here's how the company did:

• Diluted EPS: a loss of $17.71 per share vs. $34.34 consensus estimate
• Revenue: $641.1 million vs. $864.2 million a year earlier
• Net income attributable to common shareholders: a loss of $39.0 million vs. $113.8 million a year earlier

Investment losses

Net realized and unrealized investment losses were $69 million in the quarter, compared with gains of $76 million a year earlier.

The MediaAlpha stake accounted for $54 million of unrealized losses.

MediaAlpha's share price was $9.57 at September 30, down from $12.57 at June 30. The carrying value of the stake was $171 million, from $225 million.

On November 4, White Mountains agreed to sell 5.5 million MediaAlpha shares for $13.90 per share. It will own 12.4 million shares afterward, a 21% interest.

CEO Liam Caffrey said, "Higher interest rates and a lower share price at MediaAlpha drove unrealized investment losses."

Operating units

Ark's combined ratio was 75% in the quarter, against 76% a year earlier. Its gross written premiums were $386 million, up from $366 million.

Catastrophe losses for Ark were two points in the quarter, driven primarily by losses related to the war in Iran. Ark recorded estimated losses of $10 million related to the war.

Ark expects losses from Hurricane Isaias, which made U.S. landfall in October, to be limited.

Kudu reported adjusted EBITDA of $18 million, up from $15 million a year earlier. Its total revenues were negative $5 million.

HG Global wrote a record $19 million of gross written premiums in the quarter, up 21% from a year earlier.

Distinguished reported managed premiums of $159 million in the quarter. WTM Partners' total revenues were $107 million, up from $54 million.

Capital returns

White Mountains repurchased 103,827 common shares for $217 million in the first nine months, at an average price of $2,088.39 per share.

Share repurchases in the third quarter were minimal. Undeployed capital remains at roughly $0.8 billion, Caffrey said.