IAG has updated its guidance for the year to June 30 following a review.

Its reported insurance margin guidance is revised from 12.5-14.5% to 14.5-16.5%, while the gross written premium growth guidance is cut from 5-7% to 3-5%.

MD Mike Wilkins says the group expects to report an insurance margin of 17.5% for the six months to December 31 when it announces half-year results on February 21.

“This expected first-half outcome includes strong underlying performances from each of the businesses in Australia and New Zealand, as well as a small contribution from our Asian operations.”

The revised guidance does not include a contribution from the Wesfarmers insurance underwriting businesses acquired in December. The transaction is expected to complete in the second quarter of this calendar year following regulatory approvals.

IAG has also announced its catastrophe reinsurance program for this year, which gives protection of $5.6 billion, up from $5 billion last year.

CFO Nick Hawkins says the group took advantage of favourable reinsurance market conditions to bolster key aspects.

The program includes a main catastrophe cover for losses up to $5.5 billion and a $100 million upper layer that gives earthquake cover for Australia and New Zealand.