After the third-quarter of 2025, White Mountains has reported that its investment into the Outrigger Re collateralized reinsurance sidecar that supports its P&C insurance and reinsurance subsidiary Ark has generated pre-tax income of $40 million from the current underwriting year, up on last year.By September 30th 2025, the firm’s investment into the Outrigger Re sidecar structure had delivered pre-tax income of $40 million from the current underwriting year, $28 million from the 2024 underwriting year and $76 million from the 2023 underwriting year.That’s despite , which meant current underwriting year pre-tax income was just $0.3 million for the sidecar after the first-half, while the combined ratio was 120%.Which all shows that since those wildfires the Outrigger Re reinsurance sidecar that supports Ark’s underwriting with third-party reinsurance capital has experienced much fewer in losses, no doubt helped by the more benign environment for major catastrophe events through the second and third quarters of 2025.

The results for Outrigger Re likely read-across positively for other reinsurance sidecar structures, which will similarly have been most affected by the wildfires in Q1 this year.This was also reflected in the combined ratio, as Q3 2025 saw the WM Outrigger Re segment, which represents White Mountains investment in the sidecar, reporting a 38% CR compared to 58% in Q3 2024.For the nine months, the combined ratio was 63% in 2025, still slightly up on the prior year’s 50%, and this was driven by $19 million of losses related to the California wildfires (net of reinstatement premiums), the company explained.

On premiums written by the sidecar investment White Mountains said, “WM Outrigger Re reported gross written premiums of $4 million and $84 million and net earned premiums of $44 million and $63 million in the third quarter and first nine months of 2025 compared to gross written premiums of $9 million and $82 million and net earned premiums of $45 million and $63 million in the third quarter and first nine months of 2024.” The company continued to explain that income was up in Q3, saying, “WM Outrigger Re reported pre-tax income of $29 million in the third quarter of 2025, all of which was attributable to the 2025 underwriting year.WM Outrigger Re reported pre-tax income of $22 million in the third quarter of 2024, all of which was attributable to the 2024 underwriting year.” For the first nine months of 2025 net income reached $30 million, based on $40 million from the 2025 underwriting year and a -$10 million loss from 2024 business.Which compares to $40 million of net income earned for the nine months of 2024, so the run-rate is still down at this time, but the current underwriting year is performing better thanks to the strong Q2 and Q3 in 2025.

For Ark itself, White Mountains P&C insurance and reinsurance subsidiary, whose business the Outrigger Re sidecar supports, CEO Ian Beaton said, “We have enjoyed good results for the first three quarters of 2025.  Ark’s combined ratio was 76% for the third quarter and 84% year-to-date, both better than prior year.  Gross written premiums were $2.3 billion year-to-date, up 18%, aided by the addition of new underwriting teams and classes of business.” Ark’s combined ratio fell to 76% for the third quarter and 84%  for the first nine months of 2025, compared to 79% and 85% in the third quarter and first nine months of 2024, while gross written premiums neared $2.29 billion for 2025 so far, up from last year’s $1.943 billion.Find details of numerous reinsurance sidecar structures and investments in our directory of ..All of our Artemis Live insurance-linked securities (ILS), catastrophe bonds and reinsurance can be accessed online.

Our can be subscribed to using the typical podcast services providers, including Apple, Google, Spotify and more.