XL’s acquisition of Catlin is expected to lead to savings of $US250 million ($321 million), up from the original $US200 million ($257 million) estimate.

XL Catlin CEO Mike McGavick says he is delighted with developments since the merger was finalised a month ago.

Savings will be achieved through “synergy benefits”, including reducing staff overlap and process improvements.

Mr McGavick says he is confident of delivering the $US250 million figure, “but we aren’t done looking, and that number could go higher”.

There were concerns renewals at the start of the year might be hit by rumours of the merger, but the group has reported modest premium growth and positive trends continued into April.

The merger has made XL Catlin the eighth-largest reinsurer, up from 13th for XL and 19th for Catlin.