White Mountains lifts book value per share 18% after Bamboo sale

Bermuda-based re/insurer White Mountains reported an 18% rise in book value per share for year-end 2025, with results strengthened by the previously flagged sale of Bamboo.

Total net income for year-end 2025 was $1.1 billion compared to $230 million at year-end 2024. 

Subsidiaries reported largely favourable results: 

Ark’s combined ratio remained flat, landing on 82.7% for the full year 2025 compared to 83.1% in the same period the previous year. Gross written premiums saw a marginal increase to $2.6 billion up from $2.2 billion. Net income increased to $97 million from $79 million.

WM Outrigger saw an improvement in combined ratio to 57.3% at year-end 2025, compared with 60.3% at year-end 2024, with gross written premiums dipping slightly from $86 million to $84 million. Net income also dropped to $9 million from $11 million year-on-year. 

That was balanced by HG Global’s net income, which was up to $27 million at year-end 2025 compared to $23 million in the prior year. Gross written premiums rose from $52 million to $61 million year-on-year. 

Kudu’s net income rose from $67 million at year end in 2024 to $79 million in 2025.

Liam Caffrey (pictured), CEO, said: “We had an excellent year, with book value per share (BVPS) growth of 18% in the quarter and 25% for the year. The largest contributor in both periods was the net gain from our sale of Bamboo, which added roughly $320 to BVPS in 2025.

“We also benefitted from solid results at our operating companies and good investment returns. For the year, Ark produced an 83% combined ratio and $2.6 billion of gross written premiums, up 16%. HG Global generated $61 million of gross written premiums, driven by a record year at BAM. Kudu produced a 13% return on equity and grew the fair value of its portfolio of participation contracts by 8% on a same store basis. 

“Distinguished is off to a solid start under our ownership, generating managed premiums of $145 million in the quarter across both its scaled and growth programs. MediaAlpha’s share price was up 14% in the quarter and 15% for the year. Excluding MediaAlpha, our investment portfolio returned 2.0% in the quarter and 8.9% for the year. 

“During the quarter, we repurchased roughly $190 million of shares, inclusive of our self-tender offer. Including the distribution from WM Outrigger Re received in January, undeployed capital stands at roughly $1.0 billion.”

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