GoshawK finance director Andrew Castell is to quit in April when the group announces its results.
His position will be filled by Jon Beck, currently chief financial officer.
GoshawK was last year forced to put its Lloyd's operation - Syndicate 102 - into run-off and restructure itself around its Bermuda-based reinsurer, GoshawK Re.
In a trading update this week the group described GoshawK Re's 2003 trading as "creditable", given that it was hit by a temporary suspension of its credit rating and the blow caused by the failure of the group's Lloyd's business.
The formal transfer of the syndicate to a run-off manager was expected by the end of April.
Cost cutting at GoshawK Re was underway and the benefits were expected to be felt before the end of March.
The company said it was concentrating on a core mix of short-tail lines in which its underwriters had particular experience and successful track records.
GoshawK chairman Paul Spencer said: "We are pleased with the performance of the team in Bermuda in achieving a creditable showing of business in the critical January renewals, especially given the backdrop of recent difficulties."