One day after Aspen Insurance Holdings Limited announced that it expected to record an underwriting loss of approximately $245 million in the fourth quarter of 2017, including approximately $135 million in pre-tax losses, net of reinsurance and reinstatement premiums, related to wildfires in California in the fourth quarter of 2017, David Postlewhite, chief executive officer of Aspen Insurance, has left the company.

Discussing the losses, Chris O'Kane, Aspen's chief executive officer, commented: "We are deeply disappointed with our financial performance in 2017. We have taken a number of actions to improve our underwriting performance and expect to see the impact of these reflected in our 2018 underwriting year results and beyond. We believe our capital position is appropriate to support our ongoing business and underpins our financial strength ratings."

Aspen said in a statement that David Cohen, the president and chief underwriting officer of Aspen Insurance, will lead the day-to-day management of the insurance business, reporting to Mr. O'Kane.

Mr. O'Kane said: "David joined Aspen in November 2015. 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."