Argo Group posted a net loss of $43.6 million for the fourth quarter of last year, driven by a fall in the market value of its equity investments during the last three months of the year.

However, the Bermudian-based insurer and reinsurer managed to grow gross premiums written to $3 billion for the full year, an increase of 9.6 per cent from 2017.

Adjusted operating income was $18.8 million, or 55 cents per share for the quarter and $111.7 million, or $3.22 per share for the year.

Full-year net income for 2018 was $63.6 million, up from $50.3 million in 2017.

The combined ratio — the proportion of premium dollars spent on claims and expenses — was 99.5 per cent for the quarter and 97.9 per cent for the year.

During the fourth quarter, Argo said it recognised the change in the fair value of its equity securities as a pre-tax loss of $83 million, or $66.4 million net of taxes, or a loss of $1.96 per diluted share.

“Our results in 2018 demonstrate the continued execution of our strategy to optimise the efficiency of the platform, grow in lines with the most profit potential and scale the business globally,” said Mark Watson, Argo’s chief executive officer, said.

“Our business has been performing well against a difficult market environment. We posted 9.6 per cent growth in annual gross written premiums including a 12.1 per cent rise in the US, improvements in current year margins, and a 260-basis-point improvement in the annual expense ratio.

“While late year volatility in the investment markets masked the full impact of our solid results, we believe we are well positioned to continue to deliver strong shareholder value.”

Book value per share was $51.43 at December 31, 2018 compared to $53.46 at December 31, 2017.

Argo’s shares rose 35 cents, or 0.5 per cent, in New York Stock Exchange trading today ahead of the release of the results.