'Personal reasons' reportedly led to the abrupt exit of Rich Hamilton (57), chief executive officer of Publicis Groupe's ZenithOptimedia Americas.

According to the New York-headquartered agency, Hamilton has taken "leave of absence" - although the swift reallocation of his responsibilities suggests he is not expected to return.

The ceo hotseat is now filled by Tim Jones, ZOA chief strategy officer whose former remit covered business development, communications planning and the magazine group.

However, Jones doesn't inherit Hamilton's responsibilities for ZOA's Canadian and Latin American operations. Instead, the line of reporting has been shortened and Sunni Boot, ceo for both regions, now reports direct to Steve King, ceo of ZenithOptimedia Worldwide in London. As does Jones.

Mike Drexler will continue as ceo of ZO USA and Wendy Marquardt has been promoted to chief operating officer of Zenith Media USA.

Hamilton looks back on a thirty-year media career, starting as a planner at Benton & Bowles in 1975. In 1997 he joined Zenith Media as ceo, surviving four changes of ownership to become ceo of the combined ZenithOptimedia in the Americas.

Corporate lips are zipped as to the reasons underlying Hamilton's abrupt quittance - while the man himself "could not immediately be reached".

The only formal statement on the mystery came from London, where supremo Steve King substituted hype for fact: "Being able to accomplish these changes within the existing management speaks volumes to the commitment, talent and leadership qualities of this team," he said.

Data sourced from AdWeek (USA); additional content by WARC staff