The World: New York - ZenithOptimedia's Rich Hamilton takes his leave

Rich Hamilton, the chief executive of ZenithOptimedia Americas, is leaving the company after 20 years for an unspecified length of time.

A statement released from the company said Hamilton was taking "leave of absence", citing unspecified personal reasons for his decision. The company refused to give out any further information.

The chief strategy officer, Tim Jones, has replaced him and has already made two promotions. Wendy Marquardt has taken up the post of chief operating officer and Peggy Green has been named the president of broadcast and entertainment.