Investment writedowns and catastrophe losses caught up with US insurer Liberty Mutual in the first quarter, driving net profit down 92.2% compared with the corresponding period last year.

This year’s $US28 million ($37 million) profit for the three months to March 31 is dwarfed by last year’s $US332 million ($442 million) figure.

Private equity losses totalled $US373 million ($495 million) in Q1, compared with a $US60 million ($79.6 million) income a year earlier.

Liberty Mutual booked catastrophe-related losses of $US326 million ($433 million) for the first quarter, almost double last year’s $US166 million ($220 million) corresponding figure.

September 2008 hurricanes represented $US6 million ($8 million) of the 2009 first-quarter loss total.