Aon has announced it is searching for a new president and chief executive.
Patrick Ryan, 67, will continue to serve as chief executive until a successor is named and, thereafter, will continue as chairman of the board of directors.
Andrew McKenna, who heads the board's corporate governance committee, will lead a search committee, and appoint a headhunter to search for Ryan's replacement.
Ryan said: "We have built Aon into one of the largest and most respected companies in the insurance industry, fulfilling a strategy that we had established many years ago.
"Having served as CEO of Aon and its predecessor for 40 years, it is now time for a new generation of leadership. As chairman, I will do all I can to support the new CEO in a smooth transition. Aon has the best employees in our industry, and I will continue to work with them to maintain and build key client relationships around the world."
McKenna added: "As the company's founder, Pat Ryan has become synonymous with Aon. He is an extraordinary leader, having built Aon into a globally respected franchise with all of the elements necessary to effectively compete and succeed.
"With Pat's continuing support and involvement, the board is confident that the new CEO will be able to hit the ground running, build successfully on the Aon platform, and execute on our initiatives to improve financial performance."
McKenna said of the search process: "We expect to complete the search as expeditiously as possible consistent with finding the right person to lead Aon into the future.
"We seek a proven executive who can build on our sophisticated global professional services platform, drive innovation and shareholder value, and attract and manage the industry's best talent."
