Taylor Nelson Sofres (TNS) chief executive David Lowden (pictured) has left the company. His departure is part of wider management changes within the market research company following its acquisition by WPP on Wednesday (October 29).

As part of the changes, Pedro Ros, currently TNS managing director of global clients and sectors has been promoted to chief executive of TNS Custom. He will report to Eric Salama, chief executive of WPP’s insight division, The Kantar Group.

The Custom Board will initially consist of Ros and three regional chief executives, Judith Passingham (Europe), Jamie Hall (Asia and Latin America) and David Kieselstein (North America), whose responsibilities remain unchanged.

The Kantar Group has also confirmed that several existing senior management staffers will remain. They are Josep Montserrat, chief executive of Worldpanel; Jean-Michel Portier, chief executive of TNS Media; and Elaine Riddell, chief exeutive of TNS Healthcare. All will report directly to Salama.

As part of the integration process, The Kantar Group has set up an integration team which will be led by Mike Gettle, previously chief financial officer of Millward Brown.

Lowden joined TNS as finance director in 1999 and was promoted to chief operating officer, with responsibility for the group’s regional operations, in 2003. He was appointed as chief executive in January 2006. Prior to joining TNS, Lowden was senior vice president and chief financial officer of Nielsen International, and later, AC Nielsen.

WPP acquired TNS after its £1.1bn offer was accepted following a six-month takeover battle.