Boston-based insurer Liberty Mutual has delivered a $US1 billion ($965 million) turnaround in nine-month net income, although Hurricane Sandy is poised to damage future results.

Its balance sheet was aided by a drop-off in natural catastrophe claims, with net income hitting $US1.1 billion ($1.05 billion), up from $US110 million ($105.65 million) in the corresponding period last year. Revenue was $US27.32 billion ($26.23 billion), up 6.3%.

Natural catastrophe losses for the nine months to September 30 were less than half those of the previous corresponding period, at $US1.017 billion ($977 million). Natural catastrophe losses in the third quarter alone fell 92.4% to $US45 million ($43.22 million).

The company’s other third-quarter figures were equally impressive. It reported a net income of $US465 million ($446.65 million), following a loss in the previous corresponding quarter of $US112 million ($107.58 million). Revenue was $US9.278 billion ($8.912 billion).

“Improved core operating results along with modest catastrophe losses led to much-improved net income,” CEO David Long said.

“Positive price momentum exists across most lines, with the magnitude of increases targeted to where it is needed most, workers’ compensation and property.”

However, insurance payouts from Sandy are expected to put significant strain on Liberty’s fourth-quarter earnings and beyond. Fitch Ratings says the cost of the storm will fall mostly on major US property and casualty insurers including State Farm, Allstate and Liberty Mutual Group.