Allied World Assurance Company Holdings Ltd. has announced that Mark Rosen, executive vice-president and chief claims officer for Allied World US, will retire at the start of next month.

Previously, he was general counsel and executive vice-president of Darwin Professional Underwriters Inc., responsible for the company's claims, legal, and compliance departments. Following Allied World's acquisition of Darwin, Mr. Rosen assumed responsibilities for Allied World's US claims platform.

David Bell, chief operating officer of Allied World, said: "We are sorry to see Mark go, and wish him all the best in his retirement. Mark was an integral part of Allied World's acquisition of Darwin and his time here has been invaluable.

Julianne Splain, vice-president, professional and management liability claims, has been promoted to senior vice-president, Farmington claims manager and will assume responsibility for Allied World's US claims department.