White Mountains Insurance Group Ltd, the financial services holding company domiciled in Bermuda, has reported comprehensive income attributable to common shareholders of $23 million and $224 million in the third quarter and first nine months of 2023.

That compares with $890 million and $748 million in the third quarter and first nine months of 2022.

The company said the 2022 results included the net gain from the sale of NSM of $876 million.

Results in the third quarter and first nine months of this year included $47 million and $39 million of unrealised investment losses from White Mountains' investment in MediaAlpha, compared with $19 million and $113 million in the third quarter and first nine months a year ago.

The company reported book value per share of $1,542 and adjusted book value per share of $1,588 as of September 30.

Book value per share and adjusted book value per share both increased 1 per cent in the third quarter and 6 per cent in the nine months ended September 30, including dividends.

White Mountains also includes the companies Build America Mutual, Ark, WM Outrigger Re, Kudu Investment Management, David Shield Group and Elementum.

Chief executive Manning Rountree said: “BAM generated $36 million of total gross written premiums and member surplus contributions in the quarter; primary market issuance remains below historical levels but ticked up slightly year-over-year.

“Ark produced an 81 per cent combined ratio while growing premiums 17 per cent year-over-year.

“WM Outrigger Re delivered a 44 per cent combined ratio and $37 million of pre-tax income.

“The fair value of Kudu's portfolio of existing participation contracts grew 2 per cent despite a challenging quarter for investment markets. Kudu grew annualised adjusted earnings before interest, taxes, depreciation and amortisation to $47 million and closed one new deployment in the quarter.”

He added: “MediaAlpha's share price declined in the quarter, reducing ABVPS by 1 per cent. Excluding MediaAlpha, the investment portfolio was up 1 per cent in the quarter, outperforming benchmarks.

“We were pleased to announce our acquisition of Bamboo and the launch of WM Partners. Including the Bamboo acquisition, undeployed capital stands at roughly $400 million."