XL Catlin has reported estimated pre-tax natural catastrophe losses of $US240 million ($314.68 million) for the second quarter.

About $US100 million ($131.12 million) of the losses relate to the primary insurance segment, and $US140 million ($183.57 million) to reinsurance.

The Fort McMurray wildfire in Canada accounts for $US120 million ($157.34 million) of the sum, and is largely a reinsurance loss.

“Given the facts are still developing … there is considerable uncertainty associated with the loss estimates of these events and such estimates are accordingly subject to revision,” the company says.