Stephen Postlewhite, CEO of Aspen’s insurance segment, is set to relinquish his role and depart from the business with immediate effect, the carrier has announced.

He will be replaced by Aspen Insurance president and chief underwriting officer (CUO) David Cohen, who will lead the day-to-day management of the insurance business. 

Cohen joined Aspen in November 2015. Prior to that, he was president (US) and global casualty CUO at Liberty International Underwriters. In his new role, he will report to Group CEO, Chris O’Kane.

The news comes after Aspen revealed that it anticipates booking a fourth-quarter underwriting loss of $245mn, driven by an increased frequency of mid-sized and attritional losses which largely stem from the carrier’s insurance business.

Aspen said the insurance segment losses came from a range of business lines, including the impacts of property and fire-related losses in the UK and US, as well as to a lesser extent, cyber losses and a rise in a previously reported surety loss.

Aspen CEO Chris O’Kane said that the company was taking actions to try to improve its underwriting results and that these would likely become evident in 2018.

Speaking on Cohen’s appointment, O’Kane said: “Since his arrival, he has upgraded the underwriting talent in our insurance segment, is refocusing our underwriting book and is positioning Aspen Insurance for success in the next stage of its development.

“David is a strong and well-respected leader and I am confident that as we move forward, he will drive improvements across our Insurance business.”

He added: “Steve has made a significant contribution to Aspen over the last 15 years and I would like to wish him all the best for the future.”