White Mountains’ Ark/WM Outrigger sees GWP soar as CoR improves

White Mountains has reported Q3 2025 results for its property and casualty re/insurance segment, Ark/WM Outrigger, which recorded gross written premiums of $366 million and an improved combined ratio of 73%.

Ark/WM Outrigger also saw net written premiums reach $287 million in Q3 2025, while net earned premiums grew to $542 million.

For the first nine months of 2025, the Ark/WM Outrigger segment reported a combined ratio of 83%, down from 84% in the same period of 2024, with gross written premiums of approximately $2.29 billion.

In the third quarter of 2025, Ark reported a combined ratio of 76%, an improvement from 79% in the prior-year period, reflecting minimal catastrophe losses during the quarter.

For the first nine months of 2025, the combined ratio stood at 84%, down from 85% a year earlier, with seven points of catastrophe losses primarily related to the January California wildfires.

Meanwhile, gross written premiums for Ark totalled $366 million in Q3 2025 and $2.29 billion in the first nine months of 2025, compared to $374 million and $1.94 billion in the same periods of 2024.

Net written premiums were $283 million and $1.51 billion, and net earned premiums were $499 million and $1.20 billion in the third quarter and first nine months of 2025, respectively.

According to White Mountains, growth in the year-to-date period was driven primarily by the property and specialty lines of business.

Ark reported pre-tax income of $97 million in the third quarter and $240 million in the first nine months of 2025, compared to $119 million and $202 million in the respective 2024 periods.

It is worth noting that the results included net realised and unrealised investment gains of $18 million and $99 million in 2025, compared to $53 million and $84 million in 2024.

Finally, WM Outrigger Re posted a combined ratio of 38% in the third quarter and 63% for the first nine months of 2025, compared to 58% and 50% in the corresponding periods of 2024.

Catastrophe losses for the year-to-date period included $19 million of losses related to the California wildfires, net of reinstatement premiums.

WM Outrigger Re recorded gross written premiums of $4 million in the third quarter and $84 million in the first nine months of 2025, while net earned premiums were $44 million and $63 million, consistent with the prior-year periods.

The segment delivered pre-tax income of $29 million in the third quarter of 2025, all attributable to the 2025 underwriting year, compared to $22 million in the prior-year quarter.

For the first nine months of 2025, pre-tax income totalled $30 million, including $40 million from the 2025 underwriting year and a loss of $10 million from the 2024 underwriting year.

This compares to pre-tax income of $40 million in the first nine months of 2024, which included $36 million and $4 million from the 2024 and 2023 underwriting years, respectively.

Cumulatively through September 30, 2025, WM Outrigger Re has generated pre-tax income of $40 million from the 2025 underwriting year, $28 million from 2024, and $76 million from 2023.