Stuart Bridges, the chief financial officer at Hiscox, is set to depart from the company after 16 years of service.
Bridges will remain in office until August 31, 2015, after the publication of Hiscox's half year results in late July.
Following his departure, he will join markets operator and provider of post trade risk mitigation and information services, ICAP, as group finance director.
ICAP said that Bridges will sit on the global executive management group and board of ICAP, will be based in London and will report to Michael Spencer, group chief executive officer.
Robert Childs, chairman of Hiscox, said: "Stuart has made a major contribution to the strategic and financial evolution of Hiscox. His steadiness under fire, particularly demonstrated in the aftermath of the terrible events of 9/11, testing hurricanes in 2005 and the financial crisis, has been of immense value to the group. He leaves with our sincerest thanks and we wish him every success in his new role."
Bridges added: "While I am excited about my new role, I am sad to be leaving Hiscox and I will continue to follow the company's success closely, both as a former board member and a shareholder. I wish the board and the company well, and will be fully devoted to the group until my departure in the summer."